Vegetable & Herb Gardening

Please Note: All recommendations are for central Maryland.  Time frames shift two weeks earlier in Southern Maryland and the Eastern Shore and two weeks later for Western Maryland.  Check publications for further information.

For more vegetable gardening tips, visit our Grow It Eat It website and Watch our Grow It Eat It Vegetable Gardening Videos

JANUARY

• Harvest protected salad greens on sunny days in the afternoon to minimize problems with high nitrate levels in the leaves. Harvest winter salad greens by shearing the top one-third of the plants and allowing them to re-grow.

• Carrots, parsnips and turnips can be over-wintered by covering the bed with a deep straw or leaf mulch. Then cover the straw with a tarp. Harvest these root crops through the winter as needed.

• It’s a good time to check the germination rate of old, questionable seed. Place 20 seeds between moistened paper towels roll up the towel and place it in a plastic bread bag. Put the bag on top of the refrigerator or other warm location and check after 5-7 days to see what percentage has germinated. Discard seed lots with less than 75% germination.

• Indoor herb plants benefit from daily misting and full sun windows. Avoid placing plants near drafty windows or doors.

• Dried herbs should be stored in a cool, dark location away from heat sources. Herb plants inside the house should be kept in full, direct sunlight or given 14 hours of fluorescent lighting each day. Keep plants away from drafts and heat sources.

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FEBRUARY

• Consider last year’s garden successes and failures, and map out your revised garden plan for this year.    See our Grow It Eat It website for more vegetable gardening tips.  To maximize your garden’s yield, do succession planting. That means that a new crop should be seeded or transplanted in an area vacated by a crop that is overly mature, has stopped producing, or is badly damaged. Order your garden seeds now so that you will be ready to sow seeds at the proper time.

• Consider purchasing some floating row cover material to protect crops against insects and promote early growth. A floating row cover is a light weight spun fabric that permits light and water to enter, traps the soils natural heat and keeps out many pest insects.

• Did your tomato, eggplant and pepper plants flop over last year? Construct or purchase strong supports for these plants with wire fencing, wood or metal stakes.

• Later this month, you can start sowing seeds of early season greens such as spinach, lettuce, kale, mustard, sorrel, corn salad and other greens indoors under fluorescent tubes. These plants tolerate cool soil temperatures and will be ready to transplant outdoors in 4-5 weeks but should be protected by a cold frame or floating row cover until warmer weather arrives. Or you could direct seed these crops in loose, fertile garden soil cover with a cold frame or under a floating row cover. Start the seeds of long-season chile peppers indoors under lights in late February. Herbs such as rosemary, thyme, and lavender seeds can also be started indoors in late February. For more vegetable planting dates, see GE 007 Vegetable Planting Calendar for Central Maryland.

• When growing flower, vegetable or herb transplants follow a few simple guidelines:
  • Use a soilless growing medium containing peat moss, perlite or vermiculite.
  • Keep the medium moist, but never soaking wet. Speed up germination by providing bottom heat and keeping temperatures at 70-75 degrees F.
  • Use cool white fluorescent tubes and leave them on for 14-16 hours each day. Keep seedlings 1-2 inches from the lights.
  • Pot plants up to larger pots so they don’t become root-bound.
  • Fertilize transplants that have to be grown for more than 6 weeks, with a weak soluble fertilizer according to label directions.

• It’s a good time to check the germination rate of old, questionable seed. Place 20 seeds on a moistened paper towel, roll up the towel, and place it in a plastic bag. Put the bag on top of the refrigerator or other warm location and check after 5-7 days to see what percentage has germinated. Discard seed lots with less than 75% (15 out of 20 seeds) germination.

• Fresh tarragon, rosemary, and mint sprigs can be purchased in food markets and rooted indoors in a “soilless” potting mix to be grown under cool white fluorescent bulbs. The new plants can then be set outdoors in pots or garden beds in May.

• Occasionally, rosemary over-wintered indoors may develop a white coating, a sign of the powdery mildew fungus. The disease usually disappears after plants are moved back outside. Plants can also be sprayed with “ultra-fine horticultural oil” to control this disease. Follow the label waiting period and thoroughly wash what you pick before eating it.

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MARCH

• After this month, spring will arrive fast, so get your seed orders in and complete your garden plans. Be prepared to keep a variety of crops growing throughout the season so that no space is wasted.

• Some gardeners like to use seeds left over from last year. Check their viability by doing your own germination test. Place 20 seeds on a moistened paper towel, roll up the towel and place it in a plastic bread bag. Put the bag on top of the refrigerator or other warm location and check after 5-7 days to see what percentage has germinated. Discard seed lots with less than 50% germination.

• Work 1-2 inches of compost into your vegetable beds as soon as the soil is workable.

• Potatoes, onion sets, onion seedlings and peas can be planted as soon as the soil can be lightly worked. Chinese cabbage, leeks, beets, kale, mustard, and turnips can also be planted now. Start sowing spinach and lettuce seed outdoors in cold frames. You can also start sowing seeds of spinach, lettuce, kale, mustard, sorrel, corn salad and other greens indoors under fluorescent tubes. These plants will be ready to transplant outdoors in 2-3 weeks and should be protected by a cold frame or floating row cover. It is still too early to start tomato transplants. Pepper plants are very slow growing and can be started indoors in March.

• Consider purchasing some floating row cover material (GE 004) to protect crops against insects and promote early growth. Floating row covers are made from a spun-bonded polyester material and are available from mail-order seed and garden supply companies.

• When growing flower or vegetable transplants (FS 551) follow a few simple guidelines:
  • Use a soilless growing medium containing peat moss, perlite and vermiculite.
  • Keep the medium moist, not soaking wet.
  • Speed up germination by providing bottom heat and keeping temperatures at 70-75 degrees F.
  • Use cool white fluorescent tubes and run them 14-16 hours each day. Keep seedlings 1-2 inches from the lights.
  • Pot plants up to larger pots so they don’t become root-bound.
  • Fertilize transplants that have to be grown for more than 6 weeks, with a weak soluble fertilizer according to label directions.

• Rosemary, thyme, lavender, sage, basil, and tarragon seeds can be started indoors in late March. Fresh tarragon, rosemary, and mint sprigs can be purchased in food markets and rooted indoors in a soil- less mix to be grown under cool white fluorescent bulbs. The new plants can then be set outdoors in pots or garden beds in May. (FS 566 Some Easily Grown Herbs)

• Now is the time to cut back last year’s old perennial herb plants. This will make them look better and make room for new growth.  It will also help reduce insect and disease problems.

• March is also a good time to divide over-grown rhubarb plants and top dress with a balanced fertilizer or well-rotted horse or cow manure. Weeds in asparagus and rhubarb beds can be difficult to control because they are so entangled with the crop plant. It is always best to hand-pull weeds or cut them off cleanly at the soil line with a small, sharp hoe. Be careful not to cut into crowns or emerging spears. All old asparagus foliage should have been cut down and composted by this time.
  

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APRIL

For more vegetable gardening tips, visit our Grow It Eat It website and Watch our Grow It Eat It Vegetable Gardening Videos

• Turn under oats, vetch, rye and other fall-planted cover crops in the vegetable garden. They will require a few weeks to break down in the soil prior to planting vegetable crops. Do not add fresh farm manure to vegetable beds. Soluble fertilizers can be applied to the foliage or root-zone of spring crops to get them off to a fast start. Seaweed extracts, fish emulsion, and compost teas are examples of liquid fertilizer used by organic gardeners.

• Continue to start sowing seeds of spinach, lettuce, kale, mustard, and other greens indoors under fluorescent tubes. (See Grow It Eat It's Starting Seeds Indoors) These plants will be ready to transplant outdoors in 2 weeks and should be protected by a floating row cover (GE 004). Or direct seed these crops in loose, fertile garden soil covered with a cold frame or floating row cover.

• Tomato, eggplant, and pepper, seeds can still be started indoors under lights. They need 6-8 weeks to grow to a good size for transplanting. Keep the medium moist, not soaking wet. Seedlings may keel over and die due to pathogenic water molds if the mix remains too wet. (Watch our Seed Starting Videos for step by step instructions.)

• The key factors in getting early tomatoes are:
  • Select early season cultivars that are supposed to ripen 55-65 days after transplanting.
  • Warm the soil where the roots grow and the air where the plant grows. Lay down either black or clear plastic 2-3 weeks before planting to warm the soil.
  • After planting, surround the transplants with some type of plastic enclosure open at the top. A tomato cage surrounded by clear plastic sheeting works well. Fill plastic soda bottles with water and line them up inside the cage close to the plants. The water will heat up in the day and release the heat at night. Be prepared to throw a quilt over the cage on nights when the temperature dips into the 30s. Wall-O-Water is a commercially available plant protector that has produced good results for local tomato gardeners.

• Beans and corn can be sown where soil temperatures are above 50°F. Consider pre-sprouting the seed indoors to get them off to a fast start in the garden and eliminate the need for thinning. Squash, melon and cucumber plants can be started indoors now as well and grown for 2-3 weeks before transplanting into the garden. This early start may help you avoid problems with the squash vine borer. Be prepared to protect young plants from cucumber beetles using an insecticide, repellent or row cover.

• Avoid the temptation to set out warm season crops until after all danger of late frosts. This would be late May in Western Maryland, May 10-15 in Central Maryland and April 25-May 5 in Southern Maryland and on the Eastern Shore. (See our frost/freeze dates table.) Cool night temperatures in April will cause the first tomato fruits to become deformed or “cat faced”. Be prepared to cover tender transplants with paper bags, blankets or other materials if frosts are anticipated.

• “Harden-off” transplants one week prior to transplanting to toughen the plants and ready them for outdoor conditions. This is done by leaving transplants in a protected outdoor location for 4-8 hours each day and returning them indoors before dusk. Plants are further hardened by cutting back on fertilizing and watering. (Read more...)

• Mix in a handful of finely ground lime, either calcitic or hydrated, with the planting soil of each pepper and tomato transplant to prevent blossom-end rot (photo). Be sure that all plants and planted rows are clearly marked with the cultivar name and date planted.
  

• Poor germination, spotty emergence and weak stands of vegetable plants may be caused by seed corn maggots (photo) that attack large seeds and small seedlings during cool, wet springs. You can minimize problems by pre-germinating corn and bean seed indoors from mid- to late-April planting. (Read more...)

• Cutworms (photo) are nocturnal pests of vegetable plants that chew through plant stems and drag young plants into underground burrows. Place a cardboard or plastic collar around plants to prevent feeding or apply a rough or gritty material, like ground up oyster shell or sharp sand, around vulnerable plants. ( Read more...)

• Rosemary, thyme, lavender, sage, basil, and tarragon seeds can be started indoors at this time. Fresh tarragon, rosemary, and mint sprigs can be purchased in food markets and rooted indoors in a soil less mix to be grown under cool white fluorescent bulbs. The new plants can then be set outdoors in pots or garden beds in May.

• If you had trouble with southern blight on herbs in past years consider creating a raised bed. The improved water drainage will reduce the incidence of soil borne diseases. (Read more...)
  

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MAY

For more vegetable gardening tips, visit our Grow It Eat It website and Watch our Grow It Eat It Vegetable Gardening Videos

• Pinch the blooms off flower and vegetable transplants before you set them out. This will help direct the plants’ energies to root development and will result in more productive plants. Gently breakup the roots of root-bound transplants.

• Begin setting out transplants of warm season crops like squash, peppers, eggplant and tomato. Be prepared to cover plants with a tarp or light blanket if frost is expected. Mix in a handful of either finely ground calcitic or hydrated lime with the planting soil of each pepper and tomato transplant to prevent blossom-end rot. Set up your tomato support system after transplanting. Very tall tomato transplants can be laid horizontally in a shallow trench with the growing tip gently bent into vertical position. Roots will grow all along the buried stem. Corn, beans and other tender crops can also be planted. Hold off on planting pumpkins until mid June so that harvest occurs closer to Halloween. Be sure not to plant tender annual plants like basil and eggplant until after the last frost date. Parsley is slow to germinate and basil should not be directly sown in the garden until the soil has thoroughly warmed.

• For an extra boost, apply a soluble liquid fertilizer to the foliage or root zone of newly set plants to get them quickly established.

• Did your garden get over taken by weeds last year? Take action now, before weeds become unmanageable. Consider the following options around plants and between rows: dried grass clippings, sections of newspaper covered with straw, black landscape fabric or black plastic mulch. The latter two will also warm the soil and hasten the harvesting of warm-season vegetables like melons, eggplant, tomatoes and peppers.

• Now that it is warming up, you’ll begin to see slugs feeding on all types of vegetable plants. They feed at night and chew holes in leaves and can also shred leaf tissue with their rasping mouthparts. Slime trails are a definitive sign of slug activity. They breed in protected, damp areas under boards, in ground covers and under thick mulches. They can be trapped with shallow pans of water with bread yeast or beer. You can also lay out boards to attract them to be collected and destroyed. Diatomaceous earth, sharp sand or ground crab and oyster shell can be applied around plants as physical barriers. A product containing iron phosphate is available that slowly poisons slugs upon ingestion. This product is safe to use around food crops.

• Salad greens should be grown in rich soil and regularly watered and fertilized for optimum succulence and eating quality.

• Are you wondering about planting heirloom tomatoes this summer? The Home and Garden Information Center has tested and recommends the following varieties: Golden Queen, Prudens Purple, Brandywine, Georgia Streak, Cherokee Purple, German Johnson, Belgian Giant, Amish Paste, Pineapple, Tappy’s Finest, Green Zebra, and Mortgage Lifter.

Insect Pests and Plant Problems

• Cucumber beetles are either yellow with 11 black dots or yellow with 3 black stripes. They have a wide host range and begin to feed on all plant parts of all members of the cucumber family as soon as they begin to grow in the garden. These pests spread bacterial wilt disease, primarily to cucumber and muskmelon, which causes plants to wilt and die in a short time. The beetles can be controlled with insecticides or excluded with floating row covers. “County Fair” is a hybrid cucumber cultivar that is resistant to bacterial wilt disease. (Read more about cucumber beetles)

• Cutworms are nocturnal caterpillars that feed on leaves and stems and can cut large plants off at ground level. (photo) They can be excluded with cardboard, plastic, or aluminum collars inserted into the soil around individual plants or apply a rough or gritty material, like ground up oyster shell or sharp sand, around vulnerable plants.

• Aphid numbers are high now on a wide variety of landscape and garden plants. It is usually not necessary to spray insecticides or release beneficials to control aphids. Populations of lady bird beetle, green lacewings and wasp parasites build up quickly to keep aphids in check. You'll see these predators and parasites at work if you observe the aphid colonies closely. Planting a wide variety of flowering plants that bloom throughout spring and summer will help attract and keep beneficial insects in your landscape. If necessary, an application of insecticidal soap or ultra fine horticultural oil will kill these soft bodied pests. Avoid pesticides if beneficial insects are present. (Read more...)

• Squash vine borer adult females are large, clearwing moths with orange/black bodies. (photo) They begin flying mid-late May in Central Maryland and lay eggs on squash stems, especially zucchini. Use floating row covers to exclude the adult females. (GE 004)

• Seed corn maggot feeds on corn and bean seed and young vegetable plants. To avoid seed corn maggot and bird damage, try pre-sprouting bean and corn seed. (Read more...)

• Protect broccoli, cauliflower and cabbage plants from the imported cabbageworm with floating row covers. The adult is a small white butterfly with brown spots on the wings. (photo) The small velvety larvae that emerge from eggs laid on your plants can be controlled with a spray of Bacillus thuringiensis, also known as B.t. or Spinosad. This organic, microbial insecticide acts as a stomach poison on young larvae. Floating row covers are made from a spun-bonded polypropylene material and are available from mail-order seed and garden supply companies. They are effective at excluding insect pests and promoting strong early growth.

• Weeds in asparagus and rhubarb beds can be very difficult to control. It is always best to hand pull weeds or cut them off cleanly at the soil line with a small, sharp hoe. Be careful not to cut into crowns or emerging spears. Asparagus beds that are 3-4 years old should not be harvested for more than 2 weeks. In some established beds, spears may come up weak and thin. This could be due to many factors including: over-crowding, insufficient fertility, weed competition, fusarium crown rot, cutting for too long a period the previous spring or cutting ferns down in summer rather than allowing them to grow through the first frost in fall. Asparagus beetle adults feed on spears (photo) causing scaring and the females lay small black eggs (photo) resembling specks of soil. (Read more...)

• Four-lined plant bugs are now feeding on a wide range of woody and herbaceous plants, especially mint. The adults are yellowish-green with 4 black stripes. (photo) The nymphs are bright red. The bugs leave rows of small, round dark spots on leaves. Unless severely injured early in the season, plants will outgrow moderate feeding damage.

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JUNE

Check out the GE 003 - Monthly Tips for Food Gardeners

• Spring is the season that many homeowners are applying herbicides to their lawns. Unfortunately, every year we hear reports and receive samples of tomato plants damaged by lawn herbicides, especially 2,4-D, that have drifted into gardens. Tomatoes are very susceptible to herbicide injury. New leaves will become strappy, twisted and distorted. The plants may grow out of the damage and produce a crop. Often the damage is so severe that replanting is needed.

• The suckers or succulent shoots that develop from tomato plants at the soil line should be removed throughout the season. You can plant these suckers for a late crop.

• Now is a good time to plant a second crop of radishes, beets, and beans to make full use of available garden space. (HG 16)

• Perpetual spinach, Malabar spinach, amaranth, sweet potato leaves, and Swiss chard are good heat tolerant salad greens for Maryland. ‘Grand Rapids’, ‘Red Sails’, ‘Deer Tongue’ and oak-leaf type lettuces are some of the more heat tolerant looseleaf lettuce varieties that can be sown now. ‘Jericho’ is a heat-tolerant romaine cultivar. Keep them fertilized and watered and covered with a shade cloth or floating row cover if possible.

• Control weeds by laying down sections of newspaper covered with straw or last fall’s mulched leaves.

• Be sure to get stakes for tomatoes, cucumbers and pole beans in the ground right after transplanting or emergence. Doing this later in the season when they have grown large is difficult to do and may lead to some root and plant damage.

• Spinosad is an excellent organic insecticide that controls beetles, caterpillars and leafminers.

• Many species of insects become troublesome to vegetables this month. Aphids continue to feed on a wide variety of vegetable plants. It is not necessary to spray chemical insecticides. If necessary, an application of insecticidal soap or ultra fine horticultural oil will kill aphids, spider mites, whitefly and thrips. Even if you do nothing, native beneficial insects will attack the aphids and keep their numbers in check.

• Handpick Colorado potato beetles and their orange egg masses on eggplant and potato plants. A floating row cover also works well to exclude Colorado potato beetles and straw mulch can also help control this pest. (Read more...)

• Cucumber beetles can be either yellow with 11 black dots or yellow with 3 black stripes. They have a wide host range and begin to feed on all plant parts of all members of the cucumber family as soon as plants emerge. These pests transmit bacterial wilt disease, which causes mature cucumber, muskmelon, and squash plants to wilt and die. Controlling this pest early in the season is very important. Row covers can be used to cover plants to deter cucumber beetles or you can apply a labeled insecticide. Remove row covers when plants begin to bloom to permit pollinating insects to enter and pollinate the flowers. (Read more...)

• Cutworms, 1-inch long caterpillars, cut down seedlings and transplants at ground level and drag the plants into underground burrows. They can also strip foliage leaving bare stems. Try placing a cardboard collar around vulnerable plants that extends 2 inches down into the soil. The collar works very well to prevent the cutworms from getting to the stems.

• Flea beetles are a serious pest of eggplant and also affect potato, tomato and members of the cabbage family. The small black insects jump (like a flea) when disturbed and produce small shot holes in leaves. If uncontrolled they can greatly limit production. Light infestations can be controlled with a dusting of wood ash. Floating row covers are also effective but should be removed when plants flower to allow for cross-pollination by bumblebees. Spraying plants with “Surround” (kaolin clay) creates a white particle film that can minimize flea beetle feeding. You can also control flea beetles with “Neem”, a botanical insecticide. (Read more...)

• Imported cabbageworm is appearing on broccoli and cabbage. They are small, cream colored caterpillars that become velvety green when fully grown. They chew large irregular holes in leaves and leave black droppings. Handpick them or spray with a B.t. (Bacillus thuringensis) product when larvae are small.

• Harlequin bugs are very colorful black and orange insects that feed on plants in the cabbage family. The adult females lay barrel-shape white eggs with black rings. Also, look for and destroy the copper colored eggs of squash bugs on the undersides of squash and pumpkin leaves. (Read more...)

• The adults, larvae and eggs of Mexican bean beetle can be handpicked. The adults are coppery with 16 black dots and resemble ladybird beetles. Carefully inspect the upper and lower leaves of your plants for these pests and their egg masses. (Read more...)

• Slugs may cause round holes in the leaves of many different plants. Slugs reproduce around garden structures, like rock wall and railroad ties and in shaded, moist areas covered with thick groundcovers. You can control them with shallow containers of beer or a molasses, water and yeast mixture. The slugs crawl into the containers and drown. You can also set out boards and grapefruit rinds which will attract the slugs. Turn the boards and rinds over in the morning and destroy the slugs. Diatomaceous earth, sharp sand or ground crab and oyster shell can be applied around plants as physical barriers. There is a product containing iron phosphate that slowly poisons slugs upon ingestion. Be sure to carefully read the label and follow instructions.

• Squash vine borer adults are laying eggs on squash and pumpkin stems. Monitor plants for signs of wilting and entrance holes on lower stems. You may see sawdust-like frass around the hole. Stems may contain more than one larva. They can feed inside the stems for up to 2 weeks. Here’s the easiest and surest method of control: cut a slit above the hole with a razor, remove the 1 inch long white larva with a brown head, and mound up soil around the wound. (Read more...)

• Four-lined plant bugs are finishing up now. They feed on a wide range of herbs, especially those in the mint family. The adults are yellowish-green with 4 black stripes. The nymphs are bright red. The bugs leave rows of small, round dark spots on leaves. Unless severely injured early in the season, plants will outgrow moderate feeding damage.

• Young tomato plants may be exhibiting symptoms of various leaf spot diseases such as gray leaf spot, septoria and early blight. Remove badly infected lower leaves, keep a thick organic mulch around plants and avoid overhead watering. Applications of tri-basic copper will slow down severe infections. Be sure to offer proper support to growing tomato plants.

• Choanephora wet rot infects squash bloom and young fruits. The fruits shrivel and may develop a fuzzy gray growth. Prevent the problem by removing blooms attached to enlarging fruits. No sprays are recommended.

• Cut back herbs through the summer to keep plants bushy and productive. Essential oils are most concentrated right before bloom. Cut and air-dry lavender flower stalks before the florets fully open.

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JULY

• Perpetual spinach, Malabar spinach, Swiss chard, and sweet potato leaves are good heat tolerant salad greens for Maryland. ‘Grand Rapids’, ‘Red Sails’, ‘Deer Tongue’, ‘Slobolt’, ‘Bronze Arrowhead’ and all oak-leaf type lettuces are some of the heat tolerant looseleaf lettuce varieties that can be sown now. Keep them lightly fertilized and well-watered and covered with a shade cloth, or floating row cover. If you don’t have garden space grow them in containers. These greens also do fine in the shade.

• It’s time to begin thinking of fall vegetables, seed for fall crops of broccoli and cauliflower should be sown in containers by the 3rd to 4th week in July. Late crops of squash, beans and cucumbers can be direct sown through the end of July.

• Squash vine borers are hatching out and boring into squash and pumpkin vines. Monitor plants for signs of wilting and entrance holes on lower stems. You may see sawdust-like frass around the hole. Stems may contain more than one larva. They can feed inside the stems for up to 2 weeks. The easiest and surest method of control is to cut a slit above the hole with a razor, remove the 1 inch long white larva with a brown head, and mound up soil around the wound.

• The adults, larvae and eggs of Mexican bean beetle can be handpicked. The adults have 16 spots, coppery-colored wing covers and resemble ladybird beetles. The larvae are yellow with short black bristles. The adults and larvae skeletonize bean leaves. Handpick the adults, eggs, larvae and pupae.

• Blossom-end rot of tomato, pepper, squash and watermelon may be observed now. The bottom (blossom) end of the fruit bottoms becomes brown and rotted. Promptly remove any fruits that have blossom-end rot or are badly malformed. This nutritional disorder is caused by a lack of calcium in developing fruits and is brought on by dry conditions. Water your plants deeply and regularly and keep them mulched. Tomato plants may need 1-2 gallons of water each at least twice a week during droughty periods.

• Early blight of tomatoes can appear now. Small, irregular brown lesions with a yellow halo develop on lower leaves. The spots have a bulls-eye pattern. They will enlarge and entire leaves will turn yellow and then die. Defoliation can then lead to sunscald of tomato fruits. Remove badly infected lower leaves, keep a thick organic mulch around plants and avoid overhead watering. Applications of tri-basic copper will slow down severe infections.

• Are your cucumber vines beginning to wilt and die? They could be infected with bacterial wilt, a fatal disease transmitted by cucumber beetles to cucumber and muskmelon plants. Cucumber beetles are either yellow with 11 black dots or yellow with 3 black stripes. They have a wide host range and begin to feed on all plant parts of all members of the cucumber family as soon as plants emerge. There is no cure for the disease. Pull up and dispose of vines. Controlling this pest early in the season is very important. Row covers can be used to cover plants to deter cucumber beetles or you can apply a labeled insecticide. Remove row covers when cucurbit family plants begin to bloom. ‘County Fair” is hybrid pickling variety with in-bred resistance to bacterial wilt disease.

• Cut back herbs through the summer to keep plants bushy and productive. Essential oils are most concentrated right before bloom. Now is a good time to propagate herbs by stem cuttings.

• Japanese and June beetle adults are now feeding on basil foliage. Try to keep the basil picked and sweep off beetles into containers of soapy water. You could also try placing a row cover on the plants to prevent feeding damage.

• Mediterranean herbs, such as sage, lavender, tarragon and rosemary and thyme will grow best in full sun in gravelly, well-drained soil. These herbs tend not to grow or over winter as well in fertile soils high in organic matter. They may also wilt and succumb to root rots if grown in poorly drained soil. Avoid heavy organic mulches and over-watering.

• July is the month for southern blight. This is a damaging soil-borne fungal disease that attacks a wide range of herbs. Lower stems turn brown or black and plants will wilt and eventually dry up and die. You may also notice a white fungal mat growing over the infected stems along with brown dots the size of mustard seeds. In some cases only the plant tops are killed-- you can cut back the affected parts and expect re-growth. In other cases the crowns are killed and plants need to be removed. No chemical controls are available.

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AUGUST - Additional vegetable gardening tips are available on the Grow It Eat It website!

• Knowing when to harvest your garden at its peak is important. Many vegetables need to be cured or dried and then stored under proper conditions. Onions should be harvested when tops die back. Let them dry in the garden after digging or tie the stems together and hang in a garage, attic or shed. Rub soil off with hands or cloth, don’t wash. Washing can cause a rot to start while in storage. When the neck is tight and the outer scales dry, trim the tops and roots within an inch or two of the bulb and store in a cool, dry location.

• Sweet potato roots will continue to enlarge until frost so check root size to determine when to harvest. Handle harvested roots gently and cure the roots by storing them at 85ºF. and high humidity for 4-7 days. Thereafter, your sweet potatoes can be stored in a cool, dry location.

• Dig white storage potatoes on a cloudy, warm day after plants begin to die back. Let them lay on the ground for a few hours before bringing them inside. They should not be washed as this can cause a rot to occur in storage. Store potatoes in a dark, cool location (35º- 40ºF.)

• Many gardeners are unsure when to harvest watermelon and muskmelon. It’s best to leave a watermelon on the vine until the first tendril next to the fruit has turned dark brown and there is a yellowish white spot on the bottom of the watermelon. Harvest a muskmelon when it twists easily off the vine.

• Gourds should be allowed to dry on the vine and harvested prior to frost; leave 2-3 inches of stem for a handle. Let gourds cure in a well-ventilated, cool dark location. To reduce rot, rub each gourd gently with rubbing alcohol or a weak bleach solution. Don’t allow them to touch one another while drying.

• This is a good time to locate a source of garlic cloves and multiplier onions for planting in October and November. Purchase bulbs from a reputable seed company. Do not use store bought garlic for planting because of the significant risk of introducing white rot, a devastating fungal disease.

• Although it is the peak of the summer, it’s time to plant cool season vegetable crops that will mature into the fall months. These include broccoli, cauliflower, Chinese cabbage, turnips, kale, mustard, spinach, lettuce, carrots, and beets. Keep seedlings and transplants well watered and mulched. Spinach and lettuce seeds may germinate poorly in warm soils and should be sown heavily to compensate. When planting fall vegetables, be aware that more time will be required to bring the crop to maturity because of reduced light and ambient temperatures. Add at least 2 weeks to the “days to maturity” number on your seed packets. Plan to cover your newly planted garden crops with a floating row cover to protect them from pests and to extend the gardening season.

• Cover crops of oats, winter rye, crimson clover, forage radish, winter wheat and hairy vetch can be sown from late August through the middle of October. Seeds should be in close contact with soil to promote germination.

• Mexican bean beetle larvae and adults are feeding heavily and continue to skeletonize bush and pole beans. The adults are coppery in color, resemble ladybird beetles and have 16 black dots on their wing covers. The larvae are yellow and fuzzy in appearance. You can handpick them or try a pyrethrum and soap insecticide; Neem products are also labeled for use on this pest.

• Stinkbugs are active on tomatoes and peppers. They feed on the fruits producing a yellow or white “cloudy spot” directly under the fruit skin. These spots become hard but can be cut out with a sharp knife and won’t affect flavor. If stinkbugs are a problem, try handpicking or spraying pyrethrum. The spray must contact the stinkbugs to be effective.

• A second generation of squash vine borer adults is flying in Central Maryland. Monitor late crops for boring damage on stems. Well-watered squash plants that remain wilted are probably infested with the squash vine borer. Locate the borer by looking for mushy areas along the lower stem and signs of sawdust-like frass. Cut a vertical slit into the stem with a sharp knife, and locate and remove the borer. Mound up soil around the wound. The plant should recover.

• Harlequin bugs, cabbage aphids, cabbage flea beetles and several different caterpillars are all significant pests of members of the kale and broccoli family. Handpick, use a floating row cover to exclude them, or be prepared to spray with a labeled insecticide.

• Blossom-end rot of tomato, peppers, squash and melons is quite common this year. It is a physiological problem caused by extreme fluctuations in soil moisture and a deficiency of calcium in the soil. Fruits with blossom-end rot or should be pulled off the plants. Eventually as these plants become adjusted to the heat and moisture the blossom end rot problem subsides.

• Peppers that are allowed to ripen on the plant will be subject to attack by the fungal diseases alternaria and anthracnose. No chemical controls are recommended. Picking some of your peppers while they are still green will encourage the plant to produce more fruit.

• High heat can take a toll on home vegetable gardens. Excessive heating of fruit causes softening, uneven ripening, sunscald and color changes. High temperatures can prevent pepper, tomato and bean plants from forming fruits or pods. They should resume fruiting with a return to cooler weather. Hot weather may also cause lower tomato leaves to roll. Dieback of older leaves is natural, particularly when plants are stressed.

• Defoliation of tomato plants is often caused by fungal diseases like early blight and septoria leaf spot. These diseases start out early in the season as small leaf spots which enlarge and spread as the season progresses. Foliage loss often leads to reduced yields and sunburning of exposed fruits.

• If you have persistent problems with foliar diseases follow these steps next year:
  • Rotate your tomato crop to a new area of the garden.
• Increase the spacing between plants.
• Cover the soil with a mulch to prevent the pathogen from splashing from the soil to the foliage.
• Remove badly infected leaves during the growing season.
• As a last resort, spray a labeled fungicide, like fixed copper. Pull up and dispose of infected plants at the end of the season. Don’t compost these plants unless they can be shredded and hot composted.

• Fusarium wilt disease causes healthy plants, such as tomatoes, to begin wilting from the bottom up. Infected plant stems show brown discoloration of the vascular tissue. Remove and dispose of infected plants. This disease survives in soil for many years. Next year, select cultivars with fusarium resistance.

• Well-watered cucumber and muskmelon plants with wilted vines are probably suffering from bacterial wilt disease that is spread by cucumber beetle feeding. Remove infected plants and do a better job next time of controlling cucumber beetles - exclude beetles using floating row cover, plant less susceptible varieties, or as a last resort, spray pyrethrum according to label directions.

• Later this month is a good time to divide overgrown perennial herbs. Prune out damaged and dead plant parts as they appear. It is also a good time to propagate herbs by stem cuttings. When taking cuttings, snip off a 4-5 inch length of stem, remove all but the topmost leaves, and dip the bottom end in a rooting hormone and insert into a loose potting soil. Keep the cuttings moist until they become rooted, then transplant to larger containers.

• Harvest the individual leaves of tarragon, rosemary, basil, sage and other culinary herbs and dry them indoors. Herb leaves are most intensely flavored right before the plant blooms. Snip foliage in the morning after the dew has dried. To dry down herbs for storage, tie the cut stems together and hang them upside down in a dry location. Cover with a paper bag to avoid losing the shattered leaves. Store dried herbs in glass jars away from light and heat. Fresh basil can also be frozen in plastic containers. Finely chop basil and cover with olive oil. Freeze in ice cube tray, pop out and freeze in freezer bags.

SEPTEMBER

• Plant cool season vegetable crops now that will mature into the later fall months. These include Chinese cabbage, turnips, kale, mustard, spinach, and lettuce. Keep seedlings and transplants well watered and mulched. Spinach and lettuce seeds may germinate poorly in warm soils and should be sown heavily to compensate. When planting fall vegetables, be aware that more time will be required to bring the crop to maturity because of reduced light and ambient temperatures. Add at least 2 weeks to the “days to maturity” number on your seed packets. Cover your fall garden crops in September with a floating row cover or cold frame to further extend the harvest period.

• Cover crops of oats, winter rye, winter wheat and crimson clover can be sown now through the middle of October. Seeds should be in close contact with soil to promote germination. Your cover crop will protect your soil, conserve soil nutrients, and add organic matter and nutrients when tilled in next spring. You can also sow your cover crop in walkways between beds.

• Plant garlic now through the end of October for a July 4 harvest. Plant the cloves root end down; space them 4-6 inches apart and cover with 1-2 inches of soil. Mulch the garlic bed with fallen tree leaves after the green leaves emerge. Do not use store bought garlic for planting because of the significant risk of introducing diseases such as white rot.

• Dig storage potatoes on a cloudy, warm day after plants begin to die back. Let the potatoes lay on the ground for a few hours before bringing them inside. This helps them heal over any cuts or scrapes that might make them rot in storage. They should not be washed, as this increases the chance of rot in storage. Store potatoes in a dark, cool location (35° - 40°F.) Sweet potatoes should be harvested the same way except that it helps to “cure” the roots for 10-14 days in a warm, dark location (85° F.). Curing helps to heal over cuts and scrapes before being stored for the winter in a cool, dry location (55° F.)

• Sunflowers can be harvested when the backs of the flowers are dry. Cut the stalks one foot below the flower head, tie them together and hang upside down in a cool dry place.

• Cooler temperatures and shorter days will cause tomatoes and other warm season crops to ripen unevenly and be less flavorful. You may also notice seeds inside of tomato fruits beginning to germinate. This is a natural phenomenon and will not affect eating quality. Full size green tomatoes can be brought indoors to ripen. They ripen more quickly if placed in a paper bag with a banana or apple. The ethylene gas released from the banana or apple will help to ripen the tomatoes.

• Cabbage loopers, imported cabbageworms, cross-striped caterpillar, harlequin bugs, cabbage aphids, and cabbage flea beetles are feeding on members of the cabbage family. They can be handpicked or sprayed with B.t.(to control the loopers, worms, and carterpillars) or try covering crops right after they are planted with a floating row cover.
  

Herbs

• Now is a good time to propagate herbs by stem cuttings. Cut six-inch stem pieces and remove all but the top leaves. Dip the lower ends in rooting hormone and insert the stems into a moist and loose, soil-less media. Cover the pot with a perforated plastic bag and keep outside in a protected location. Pull gently on the stems in two weeks to test for root growth. Pot the cuttings up individually after they start growing and bring them indoors for use during the winter.

• Harvest the individual leaves of tarragon, rosemary, basil, sage and other culinary herbs and dry them indoors. Herb leaves are most intensely flavored right before the plant blooms. Snip foliage in the morning after the dew has dried. To dry down herbs for storage, tie the cut stems together and hang them upside down in a dry location. Cover with a paper bag to avoid losing the shattered leaves. Store dried herbs in glass jars away from light and heat. Fresh basil can be processed into pesto or frozen in plastic containers for winter use.

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OCTOBER

• Be sure to discard badly-diseased plants and fruits; don’t till them back into the soil. All other plant waste can be composted or directly incorporated into your garden soil.

• Pumpkins and winter squashes can be harvested when they are fully colored and you can’t push your fingernail into the rind. You may also leave winter squash and pumpkins on the vine until the first frost (not hard freeze) has killed the vines. Store pumpkins in a cool, dry location with good air circulation. Set them on top of cardboard or wood pallet. Be careful not to nick or bruise the fruits or they may rot in storage.

• Small ornamental gourds can also be harvested now but wait until after the first killing frost to harvest birdhouse, dipper and other large gourds. Leave 2-3 inches of stem for a handle. Let them cure in a well-ventilated, cool dark location. To help prevent rot and discoloration rub each gourd gently with rubbing alcohol or a weak bleach solution and don’t allow them to touch one another.

• Dig potatoes after plants begin to die back. Let them lay on the ground for a few hours before bringing them inside. They should not be washed as this can cause rotting in storage. Store potatoes in a dark, cool location. (Harvesting video)

• Sweet potato roots will continue to enlarge until frost so check root size to determine when to harvest. Handle harvested roots gently and cure the roots by storing them at 85°F. and high humidity for 4-7 days. Thereafter, your sweet potatoes can be stored in a cool, dry location.

• Carrots can be over-wintered in the garden by covering the bed with a deep straw or leaf mulch. Pull carrots through the winter as needed.

• Reduced sunlight and lower temperatures contribute to a number of physiological tomato fruit disorders including uneven ripening, blotchiness, poor flavor and texture and small size. You may also notice seeds inside of tomato fruits beginning to germinate. This is a natural phenomenon and will not affect eating quality.

• Pick green tomatoes prior to the first frost. They can be slowly ripened indoors by placing them in a paper bag.

• Lettuce, spinach, arugula, kale, and corn salad can be planted through the middle of the month. Cover these late plantings with a cold frame, temporary greenhouse or floating row cover. Be sure to fertilize seedbeds, keep the soil moist and protect seedlings from pests. The young plants will go dormant and re-grow in Spring.

• Garlic cloves can be planted through mid-November in deep, fertile soil. Purchase garlic bulbs from a seed catalog. Do not plant grocery store-bought garlic because they are not certified as diseasae free. Divide the planting stock into individual cloves leaving the papery wrappers intact. The largest cloves usually make the largest bulbs. Space the cloves 4 – 6 inches apart with the root end down (pointy end up) and cover with 1-2 inches of soil. Mulch your garlic bed with shredded leaves or compost after the green garlic leaves emerge.

• To improve your garden soil, try sowing a cover crop of annual rye, oats, or winter wheat in a bare area of the garden or in the walkways between crops that will grow until frost. Cover crops protect the soil from erosion, improve soil structure, and recycle soil nutrients when incorporated into the soil in early spring. Seeds should be in close contact with soil to promote germination. (GE 006)

Herbs

• Dig up small herb plants or divide large ones, pot them up in a soil-less (peat moss and perlite) growing medium and bring them indoors to provide your household with fresh herbs through the winter months. Locate them where they will receive strong direct sunlight or place them under “cool white” fluorescent lights. This is a good time to take cuttings or divisions of perennial herbs to produce additional plants. When taking cuttings, snip off a 4-5 inch length of stem, remove all but the topmost leaves, dip the bottom end in a rooting hormone and insert into a loose potting soil. Keep the cuttings moist until they become rooted, then transplant to larger containers.

• Remove all dead and weak herb plants from the garden. Harvest the individual leaves of tarragon, rosemary, basil, sage and other culinary herbs and dry them indoors. Hang herbs upside down by tying string around the stems and cover with a paper bag to catch ripe seeds and shattered leaves. Hang in a dry location. Store dried herbs in glass jars away from light and heat. Fresh basil can also be frozen in plastic containers.
  

NOVEMBER

• This is a good time to incorporate organic matter into your garden beds. Composted animal manure (horse, cow, sheep, chicken) is excellent for improving garden soil. Keep garden beds covered with shredded leaves to minimize the risk of soil erosion and nutrient run-off. These can be tilled into the garden in spring or left in place as a mulch between rows of vegetables.

• Spinach, lettuce, arugula, kale, and other cool-season crops should be protected from freezing with a cold frame, plastic sheeting or floating row cover. Be sure to vent your cold frame or plastic cover on sunny days to prevent excessive heat build-up.

• Carrots, parsnips, and turnips can be over-wintered by covering the bed with a deep straw or leaf mulch. You can harvest these root crops through the winter as needed.

• Herbs brought indoors for fall and winter should be located where they will receive strong direct sunlight. Supplemental fluorescent light (cool white bulbs or grow lights) will probably be necessary as well. Keep lights on for 14-16 hours each day. Keep herb plants away from drafts and heat sources and mist them daily.

• Remove all dead and weak herb plants from the garden. Dried herbs should be stored in a cool, dark location.
  

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DECEMBER

• Be sure to request catalogs from seed companies you might like to patronize next spring. Review garden notes from this past season as you sketch out next year’s garden plan.

• Beets, spinach, lettuce, broccoli raab and other cool-season greens that have already germinated in the fall garden should be protected with a cold frame, plastic sheeting or floating row cover. Be sure to vent your cold frame or plastic cover on sunny days to prevent heat build-up.

• Carrots, parsnips and turnips can be over-wintered by covering the bed with a deep straw or leaf mulch. Pull these root crops for table use through the winter as needed.

• Keep garden beds covered with shredded leaves or bark mulch to minimize the risk of soil erosion and nutrient run-off.

• Dried herbs should be stored in a cool, dark location away from the stove. Herb plants inside the house should be kept in full, direct sunlight or given 14 hours of fluorescent lighting each day. Place the lights close to the plants, such as only a few inches away from the tops.
  

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