Soil Preparation

Fertilization requirements are similar to those for onions. 

Propagation

Farmers generally grow leeks from seeds that they start indoors in February (similar to starting onions). You should plant your leeks in a trench or hole (often called a “dibble”) about 6 inches deep; allow rain water or irrigation to fill the hole. For full-size leeks, plants should be spaced at least 6 inches apart in row, with 24 inches between rows — to reserve ample space for hilling. You can also interplant leeks with other crops, such as kale and early spring pac choy, though this might impact blanching. 

Culture

Like onions, they compete poorly with other vegetables and weeds and need frequent weeding.

Gradually hill the leeks with soil during the growing season (two to three times) to blanch (or whiten) the stalks of the leeks. When planting in dibbles, the soil filling in around the leeks may reduce the need for extensive hilling. 

Once you start hilling the leeks, the need for weeding diminishes. 

Common Problems

Leek moth is an invasive pest of allium crops like onions, garlic, shallots and chives, and, as the name suggests, they are particularly fond of leeks. As with most moth pests the crop damage is from its larval caterpillar stage, of which there are two to three generations. Overwintered adults emerge in the spring and fly at night to both mate and seek out host plants to lay eggs on. Eggs are laid at the base of host plants, and larvae (caterpillars) emerge in about a week to begin feeding. After feeding for about two weeks, larvae pupate on the host plant, or very close nearby, emerging as adults 10 days later. Feeding damage from the first generation of the year can stunt growth as leaves are attacked, and later generations can impact storage and saleability of onions, garlic and leeks as they eat their way in the direction of the bulb. 

You can use row cover or exclusion netting to prevent adult moths from laying eggs on your crop. Row cover can be removed during the day to cultivate or harvest, as adult leek moths only fly at night.

Harvest and Storage

You can use leeks throughout the season or harvest them in the fall. To harvest, gently loosen the soil around each leek with a digging fork or spade. Leeks harvested in late fall can be packed in baskets and stored in a root cellar. Some varieties also overwinter in the garden.

Soil Preparation

Garlic grows best in well-aerated, deep, fertile soil with a pH of 6.5 to 6.7. Prepare the soil a few weeks in advance of fall planting. Work in an inch-thick layer of rich compost or a well-rotted manure.

Propagation 

Farmers plant garlic around the mid-October in central Maine. Break the head of garlic into individual cloves and plant each clove 2 to 4 inches deep, about 6 inches apart in rows that are about 12 inches apart. To protect the bulbs through the winter, cover the area with a 3- to 6-inch layer of mulch, such as straw or leaves.

Culture 

In the spring, the garlic shoots will come up right through the mulch. Keep them evenly watered but be sure not to over-water. The ground should not be so wet or the drainage so poor that the roots are sitting in water. When the hardneck varieties send up flower shoots, known as garlic scapes, cut them off; they can be used in place of garlic in cooking.

Common Problems

Three unrelated fungi cause three garlic diseases that growers should be aware of: penicillium decay, Botrytis rot and white rot. All three spread with garlic “seed” (cloves), and can be avoided by buying certified disease-free seed garlic.

Harvest and Storage 

Harvest your garlic in the summer. When the leaves start turning brown, it is almost harvest time. Garlic will store best if harvested when about half the leaves are brown, the cloves are softly bulging and the outer papery wrapper is starting to dry. Do not let the bulbs sit in the ground after they are ready to harvest or the cloves will start to break through their wrappers and they won’t store well. Pull up the bulbs when they are ready and let them cure for a few weeks in a dry, shady spot.

Don’t wash them. When they are dry, you can gently brush off the dirt. After curing, put the garlic in a cold, relatively dry place that never drops below freezing. Garlic stores very well through the whole winter.

Soil Preparation

Members of the Brassica genus (also referred to as cole crops), broccoli and cauliflower do best in rich loams with good water-holding capacity. You can grow crops on most soil types if water is available when needed. The recommended pH is 6 to 6.8.

Cole crops are quite sensitive to low pH, and, at pH above 7.2, a boron deficiency may develop, especially in cauliflower. Work manure, greensand and phosphate rock (if needed) into the soil before planting. If a soil test suggests a boron deficiency, you can create a dilute solution of household borax (0.1 pound/100 gallons of water) to use as a foliar spray.

Propagation

Broccoli and cauliflower are grown for their immature flowers. Both produce much better heads in cool weather, and you should plant them to time their flowering with early summer (plant in early spring from transplants) or early fall (plant seedlings in the garden in late June or early July). For early spring transplants, sow seeds indoors about four weeks (six weeks for cauliflower) before you expect to set the plants out. For a later crop, sow seeds in a seedbed in the garden in late spring or early summer. (See Table III.) Many varieties of cauliflower do not form good heads in warm weather; fall ripening is best.

Set out broccoli plants 12 to 18 inches apart in rows that are 18 to 36 inches apart; space cauliflower 18 inches with 24 to 26 inches between rows.

Cole crops are often set out without being hardened off in order to avoid a check in growth. Plants are somewhat hardy and will take a slight frost, but a heavier frost may kill them. Cauliflower is the most sensitive. Transplant on a cloudy day or in the evening, and water the transplants in.

Culture

Keep the soil evenly moist, avoiding long dry spells. Weed carefully, as the roots are shallow. A side-dressing of well-rotted manure or compost after plants have grown three or so weeks in the field is useful.

Cauliflower heads are kept white by blanching — tying the outside leaves together around the developing head when it is 2 to 3 inches in diameter. (Some newer varieties are self-blanching; their leaves grow around their heads naturally and do not have to be tied.) 

Common Problems

Cabbage maggots (the larvae of a fly) will attack cole crops that are set out early. Symptoms are yellowing of the lower leaves, slow growth or wilting. Injury results from maggots feeding on root surfaces and tunneling through them. The adult fly looks a bit like a small housefly and lays eggs in April or early May on the base of the plant. Eggs hatch in a few days, and the maggots crawl into the soil. Cabbage, broccoli, cauliflower and radishes are favorites. The most effective control is covering plant rows with polyester cloth (floating row cover). Dusting the base of the plant with a mixture of rock phosphate and wood ash may prevent the maggots from crawling. Beneficial nematodes, available from certain garden supply companies, may work very well.

Imported cabbageworm and the cabbage looper are caterpillars that feed on cabbage and broccoli as well as some other garden plants. They are easily controlled by the microbial pesticide Bacillus thuringiensis (Bt).

Cutworms, the larvae of a night-flying moth, are a major problem, especially for transplants. Cutworms crawl along the surface of the soil at night and sever the plant right at the soil line. Some species climb up the plant and sever leaves. The best protection is to cut the bottom from a paper cup and slip the cup over the small plant, pressing it into the soil slightly, to form a barrier that cutworms can’t pass.

Harvest

Cut out large, central heads of broccoli when they are ready and before they start to grow loose. This will promote the growth of smaller side heads.

Harvest cauliflower heads when they are still compact and fairly smooth.

Yield: 

Broccoli: 27 pounds per 50-foot row

Cauliflower: 30 pounds per 50-foot row

Soil Preparation

A member of the Brassica genus (also referred to as cole crops), cabbage does best in rich loams with good water-holding capacity. Fertilization requirements are similar to those for broccoli and cauliflower.

Propagation

For early spring transplants, sow cabbage seeds indoors about four to six weeks before you plan to set the plants out. Set out plants 12 to 18 inches apart in rows that are 18 to 36 inches apart. You can have a supply of cabbage all summer by spring planting varieties with different maturing dates. You can also grow a fall crop for storage — select a midseason or fall variety, and start seedlings in May to transplant in June or July.

Culture

See cultural requirements for broccoli and cauliflower.

Common Problems

See common problems for broccoli and cauliflower.

Harvest and Storage

Harvest when heads become tight. Mature heads do not last long in the field: They will split as they become over-mature, especially after a rain. A slice with a spade that cuts off part of the root system may prevent splitting. You can also gently twist the plant to disturb its roots. 

For winter storage, leave much of the stem attached after removing the loose outer leaves and place them sideways on a cellar shelf.

Yield: 

75 pounds per 50-foot row

Soil Preparation

Related to cabbage, broccoli and cauliflower, Brussels sprouts perform well in rich loams with good water-holding capacity. Fertilization requirements are similar to those for broccoli and cauliflower.

Propagation

Brussels sprouts require a relatively long growing season and ample space. Sow seeds indoors in May and transplant into the garden four to six weeks later. Space plants 24 inches within the row, and 34 to 48 inches between rows.

Culture

See cultural requirements for broccoli and cauliflower. 

Common Problems

See common problems for broccoli and cauliflower.

Harvest and Storage

You can harvest Brussels sprouts over a long period. Pick as soon as the buds become firm. The flavor is best after a hard frost or two.

Yield: 

80 pounds per 50-foot row

Soil preparation

Legumes require less soil nitrogen than other garden vegetables and may actually improve soil fertility as they grow and when the crop residue is turned under by adding nitrogen. They require a well-drained soil, rich in organic matter, with a pH between 6 and 7.5. Work in rock phosphate (if needed) and wood ashes (but if the pH is high, use Sul-Po-Mag instead of wood ashes). In sandy soils that are low in organic matter, a small amount of nitrogen fertilizer will be necessary to get the plants started.

Propagation

Beans are sensitive to frost, and the seed will not germinate in cool soil. Soil temperatures should be at least 60 degrees Fahrenheit. Successive plantings every 10 days to two weeks until mid-July will ensure a steady supply. Sow seeds 1 to 1-1/2 inches apart in rows 2 to 2-1/2 feet apart; 3/4 inch deep in loam soils and 1 inch deep in sandy soils.

Culture 

Bush beans can be grown without support, but pole bean varieties, such as runner beans, will require trellising or staking. Pole bean seeds should be sown around the base of the trellis system.

Common Problems

Mexican bean beetles may be pests on snap beans, soybeans and lima beans. While they are not a pest for every farm or garden, some farms report repeated significant damage from these pests and have to take action to prevent crop loss. Using biological control can reduce the need for insecticides.

Harvest

You should harvest snap beans when they reach full length and before the seeds begin to develop. Frequent harvest helps the plant to continue to produce new pods.

Harvest dry beans (such as soy or kidney beans) after the pods are brown and dry, or nearly so. Once the beans are air dried, they will store for years if kept cool and dry.

Yield:

30 pounds snap beans per 50-foot row

Soil preparation

Legumes require less soil nitrogen than other garden vegetables and may actually improve soil fertility as they grow and when the crop residue is turned under by adding nitrogen. They require a well-drained soil, rich in organic matter, with a pH between 6 and 7.5. Work in rock phosphate (if needed) and wood ashes (but if the pH is high, use Sul-Po-Mag instead of wood ashes). In sandy soils that are low in organic matter, a small amount of nitrogen fertilizer will be necessary to get the plants started.

Propagation

You can sow peas directly into the ground early in the spring after the soil temperature reaches 40 degrees Fahrenheit, although seeds that are not treated with a fungicide may show spotty germination. Better germination of untreated seeds occurs when the soil is 50 to 55 degrees. Midsummer plantings for a later crop of peas are possible but often give disappointing results because of the heat of summer.

Inoculation with nitrogen-fixing bacteria is beneficial, at least the first time the particular legume is grown in your garden. Inoculates come as a dry powder (available in most garden stores and seed catalogs). Wet the seeds and shake them around in the powder just before planting.

Peas can be planted in rows, but other methods have advantages. You can plant tall varieties on both sides of a wire fence. Plant dwarf varieties in wide rows, since they do not suffer from some crowding. Leave about 2 inches on all sides of each seed.

Culture

Tall varieties of peas require support; here are some options for trellis systems.

Their upright growth habit makes peas a good candidate for companion planting with shorter crops, such as carrots or parsnips. They can also share bed space with broccoli, summer cabbage, lettuce, early kohlrabi or green onions.

Be mindful when weeding peas — they have shallow roots and can be disturbed quite easily. 

Common Problems

Fusarium wilt of peas is a fungal disease that first appears as downward curling leaves, which become pale green and flaccid, then turn yellow, starting at the bottom and progressing upward until the entire plant it is yellow — and eventually become dry and crisp.

Crop rotation and sanitation will help manage the spread and buildup of pea wilts but are of limited value because of the persistence of the spores once they get into the soil. Use long rotations with non-pea crops. Clean trellises and stakes, physically removing any debris, to avoid bringing infected pea debris to a new area or field. By far the best control of Fusarium wilt of peas is use of resistant varieties.

Harvest

Peas are available as 1) edible pod varieties called snow peas in which the pod is harvested before the pea (the seed) develops; 2) snap peas, which offer both edible pods and peas (seeds); and 3) plain fresh peas in which only the pea (seed) is edible. The sweet flavor of peas is short-lived, so you should harvest them as soon as they ripen.

Yields: 

25 pounds per 50-foot row

Soil Preparation

A sandy loam that is well drained and contains a lot of organic matter is ideal for growing tomatoes. The pH should be 6 to 6.5. You should work in well-rotted manure or compost and a handful each of rock phosphate (if needed) and greensand into the hole which the transplants will go. Tomatoes are heavy feeders. Too much nitrogen, however, often leads to big, lush plants and delayed fruiting.

Propagation 

Tomatoes are sensitive to frost and require a long growing season. Start tomatoes indoors (by April 14, according to our seed planting calendar) and transplant seedlings after the frost-free date for your area. You should grow early and midseason varieties of tomatoes to have a supply from midsummer to fall. Ideally, plant tomato seedlings 2 to 3 feet apart in rows 4 to 5 feet apart. If the transplants are tall and leggy, plant them 2 to 6 inches deeper in the soil than they were in the pot.

Culture

Tomatoes can grow with or without a trellis, depending on whether they are a determinate (bush) or indeterminate (vining) variety. Staking, or growing with wire cages, keeps the fruit cleaner and helps prevent disease. 

Tomatoes benefit from mulch, which can help reduce diseases that otherwise splash onto plants from the soil during rains (see early blight below). But wait for the soil to warm before applying organic mulches, or use black plastic. You can get a jump on the season by using both black plastic mulch and row covers. Tomatoes also perform well when grown under cover, such as in a hoophouse.

Tomato yields are improved with pruning. Tomato pruning involves “suckering” ­— the removal of side shoots from the leaf axil (where the leaf meets the stem) that would otherwise grow to become whole new stems with their own leaves and fruit.  

Common Problems

Fruit may not set or blossoms may drop if prolonged spells of cool nights occur early in the season. Cold and hot days (over 90 degrees Fahrenheit) prevent pollination, which, of course, prevents fruit development.

Early blight is a fungus infection of the tomato leaves that may spread to the fruit. It is characterized by small, brown-yellow spots with concentric rings. The whole leaf will eventually turn brown and fall off the plant. Cool, humid conditions and shaded plantings promote the spread of the disease. The fungus overwinters on plant debris, so compost plants at the end of the season and rotate the location of the tomatoes every few seasons. Do not plant tomatoes where other family members (peppers, eggplants and potatoes) have just grown.

Cutworms can also create problems in tomato plots. Cutworms crawl along the surface of the soil at night and sever the plant right at the soil line. Some species climb up the plant and sever leaves. The best protection is to cut the bottom from a paper cup and slip the cup over the small plant, pressing it into the soil slightly, to form a barrier that cutworms can’t pass.

Tomato hornworms may be the most notorious tomato pest, however. They are giant caterpillars that can do a vast amount of eating in a very short amount of time. Sometimes it seems that healthy looking tomato or pepper plants are stripped of their leaves overnight, leaving bare stems. The hornworms will also attack fruit, eating gouges out so large that they look more like bites of a furry animal than an insect. Watch for feeding damage and frass (insect poop) around tomato and pepper plants. The frass may be your first sign there is a problem. Hand picking works well but it is easy to overlook one or two caterpillars, which can do significant damage in a day or two. Many growers use a black light at night to help find hornworms, as the caterpillars fluoresce brightly. Bacillus thuringiensis (Bt) can also be used.

Harvest 

Fruits will ripen from blossom end. Get to know the varieties that you plant so you know what ripe fruit will look like. Fruit can be harvested after any initial coloring and will continue to mature off of the plant, though the flavor will be affected. Handle soft fruit carefully. 

Yields: 

100 pounds per 50-row foot

Soil Preparation

Like tomatoes, to which they are related, peppers, grow best in a sandy loam soil that is well drained and contains a lot of organic matter. See fertility requirements for tomatoes.

Propagation 

Peppers are sensitive to frost and require a long growing season — start indoors in March. They germinate slowly and a heat mat is useful for maintaining consistently warm soil temperatures. Transplant pepper seedlings after the frost-free date 12 to 18 inches apart in rows 2 to 3 feet apart. 

Culture

Peppers sometimes benefit from staking for support. They also benefit from mulch, but wait for the soil to warm before applying organic mulches, or use black plastic. You can get a jump on the season by using both black plastic mulch and row covers. 

Common Problems

Fruit may not set or blossoms may drop if prolonged spells of cool nights occur early in the season. Cold and hot days (over 90 degrees Fahrenheit) prevent pollination, which, of course, prevents fruit development.

Cutworms can also be a problem. Cut the bottom from a paper cup and slip the cup over the small plant, pressing it into the soil slightly, to form a barrier around tender seedlings.

Tomato hornworms also attack pepper plants. Keep an eye out for feeding damage and frass (insect poop) around plants. Handpick or apply Bacillus thuringiensis (Bt) for control.

Harvest

Pick ripe peppers regularly to encourage continued production.

Yield: 23 pounds per 50-foot row

Soil Preparation

Eggplant prefer a well-drained sandy loam high in organic matter with a pH between 6 and 6.5. See fertilization requirements for tomatoes.

Propagation 

Eggplants are frost sensitive and need to be started indoors; transplant seedlings after the frost-free date at 18 inches apart in rows 3 feet apart. 

Culture

Eggplant benefit from plastic mulch and row cover early in the season for added warmth. Row cover is also helpful for insect control.

Common Problems

Fruit may not set or blossoms may drop if prolonged spells of cool nights occur early in the season. Cold and hot days (over 90 degrees Fahrenheit) prevent pollination, which, of course, prevents fruit development.

The Colorado potato beetle is especially damaging to young eggplants. The best way to control them in the garden is by hand picking both adults and larvae and crushing the bright yellow egg masses. A natural-based insecticide called Monterey Garden Insect Spray helps control potato beetles. Row covers may also be used and act as a deterrent to flea beetles as well. 

Use collars when transplanting young seedlings to protect them from cut worms.

Harvest

Harvest regularly to encourage continued fruit set.

Yield: 50 pounds per 50-foot row

Soil Preparation

Potatoes grow best in moderately fertile soil that is high in phosphorus and potassium with at least moderate amounts of nitrogen available. Excess nitrogen will encourage too much foliage at the expense of tuber formation. Work in about an inch of compost along with phosphate rock (4 pounds per 100 square feet, if needed) and Sul-Po-Mag (1 pounds per 100 square feet). Although potatoes grow best at a pH around 6.0, a pH higher than 5.7 promotes the fungal disease called scab. You should apply manure in the fall before planting; otherwise it can promote scab.

Propagation 

Potatoes are grown from seed pieces, which are pieces of the potato tuber with buds (commonly called “eyes”) on them. Although you can use old potatoes for seed pieces, this is not recommended because they commonly carry diseases. Do not plant grocery store potatoes, because, unless they are organic, they are commonly treated with anti-sprouting chemicals. Instead, buy certified disease-free potato “seed” (actual tubers).

Cut the seed tubers into pieces about the size of a hen’s egg and be sure to have at least one to two eyes on each piece. Let the cut surfaces dry for a day or two, and then plant the seed 4 to 6 inches deep, about 10 inches apart, in rows that are 2 to 3 feet apart. For larger potatoes, space seed pieces 15 inches apart in rows.

You can also “greensprout” potatoes by exposing seed tubers to natural or artificial light in a warm environment prior to planting. This process leads to the development of short, strong sprouts on the seed pieces — and may result in a faster-growing plant.

Culture 

When the plants are 4 to 6 inches high, hoe up the soil up around the plants to cover the stems. This prevents the tubers from exposure to light and turning green, and it promotes more underground stem development. Water plants during long dry spells to maintain even moisture during the season. Alternate dry and wet spells produce cavities in the tubers and knobby potatoes.

Common Problems

Colorado potato beetle is the most prevalent insect. The best way to control them in the garden is by hand picking both adults and larvae and crushing the bright yellow egg masses. A natural-based insecticide called Monterey Garden Insect Spray helps control potato beetles.

Flea beetles will attack young plants and, in large numbers, may destroy them, but are usually not severe. The best way to prevent the insects is with floating row covers.

The potato leafhopper is also a major problem some years. This is a tiny, flighty insect that sucks nutrition out of the plant. The leaves brown from the edges and often die from what looks like a disease. Scout early and through the season for the pest. Some potato varieties are much more resistant than others. For example, Norland is very attractive to them and Keuka is much less so.

Early and late blight are common fungal diseases that destroy potato foliage and infect the tubers. Late blight, one of the causes of the Irish famine in the 19th century, appears as brown-black areas on leaves and brown to purple discoloration on the skin of the tuber. The disease is carried through the winter on infected tubers. During the growing season, the spread of the disease depends on weather conditions. Spores are produced only in cool weather, below 60 degrees Fahrenheit, then invade new leaves when higher temperatures occur. A cool, wet July is often followed by blight in August and September. Some varieties (Kennebec, Essex, Cherokee, Sebago) are resistant to the common strain of blight, but not to some new strains. Copper may offer some control. If leaves become infected, delay digging tubers until a week after the first frost has killed the vines; otherwise you will infect the tubers by spores on the soil surface. Destroy infected tubers and in the following year, watch for and destroy any volunteer potatoes growing from the year before.

Harvest

Dig potatoes after the tops turn brown. Cure them for about 10 days by storing them at room temperature in the dark, then store them in a cool (40 degrees Fahrenheit), dark cellar.

Yield per 50-foot row: 60 pounds.

Soil Preparation

A well-drained soil that is high in humus is best for cucurbits. Cucumbers, along with zucchini, summer squash, melons, winter squash and pumpkins, do well when planted in hills. (A hill is not a mound of soil but a group of three to five plants.) Prepare the hill by digging a hole 10 to 12 inches deep and putting 1/2 to 1 cup of rock phosphate (if needed) and 4 or 5 cups of well-rotted manure in the bottom. Mix a cup of wood ashes with the soil from the hole and stir some of that mixture into the manure and phosphate. Then fill in the hole.

Propagation

Early cucumbers grow best from transplants started indoors four weeks before the last spring frost. Main season cucumbers are generally direct-seeded outdoors. Some gardeners transplant their first round of cucumbers and direct seed another round on the same day to ensure a longer harvest season. Space hills 3 to 5 feet apart. If planting in rows, space plants/seeds 1 foot apart in rows 5 to 6 feet apart. (If trellising, spacing can be tighter.) 

Seed will not germinate in cool soil, so wait until it reaches 60 to 65 degrees Fahrenheit if direct seeding. Cucumbers and other cucurbits benefit from warm soil and even moisture and do well planted through black plastic. Put the plastic on the soil a week or two before planting to help warm the soil.

Culture

If you did not use plastic mulch, apply a heavy organic mulch around the plants after the soil has warmed. Even moisture is essential. Side-dressing with well-rotted manure about four weeks after transplanting is beneficial.

Most cucumbers are not self-pollinating and require bees for pollination. However, gynoecious (all female-flowering plants) and parthenocarpic (plants that do not require pollination to set fruit) varieties are available, and are recommended for cucumber crops grown in tunnels. 

Cucumbers are vine fruits which will sprawl as they grow. For smaller spaces, trellising can be beneficial. Not only does training the vines to grow vertically on a support system save space, it also increases air flow in the garden — which may help reduce disease pressure. 

Common Problems 

The striped cucumber beetle can be a major pest for cucumbers and other cucurbits. Not only does it destroy leaves and sometimes fruit, but it also carries an incurable disease called bacterial wilt. Large transplants are much more tolerant than tiny seedlings germinating in the garden. Covering a plant with a polyester row cover is a good solution, but be sure to remove the row cover once the plants flower so that bees can pollinate the flowers. Pyrethrum applied once a week offers some control in serious infestations. Growing robust plants in healthy soil seems to help minimize cucumber beetle damage.

Harvest

Cucumbers should be harvested when small because they lose flavor and the texture is less desirable when large. Harvest daily since ripening fruit draws energy from the plant at the expense of other, developing fruit.

Yield per 50-foot row: 45 pounds

Soil Preparation

Melons do best in well-drained soil that is high in humus — soil preparation is similar to cucumbers.

Propagation

Melons — including muskmelons (cantaloupes), honeydews and watermelons — are a warm-season crop that do poorly during cool summers. They should be started indoors four weeks before the last spring frost. Melon seedlings will need to be handled carefully when transplanted into the garden — for this reason, many gardeners choose to plant them in peat pots so the roots will be minimally disturbed. You can also use half-gallon milk cartons, as described in this article.

Space hills (a cluster of 3 plants) 3 to 5 feet apart.  Melons do well in warm soil, so black plastic mulch is often used. Put the plastic on the soil a week or two before planting to help warm the soil. Row covers can also be added at time of transplant for extra warmth as well as insect protection. 

Culture

If you did not use plastic mulch, apply a heavy organic mulch around the plants after the soil has warmed. Even moisture is essential. Side-dressing with well-rotted manure about four weeks after transplanting is beneficial. 

If using row covers, they will need to be removed at flowering to ensure insect pollination.

Common Problems 

See “Cucumbers” for common problems.

Harvest

Melons can be tricky to harvest. Familiarize yourself with the varieties you planted so you know what to look for. 

Most varieties offer several cues of ripeness. For cantaloupes, these signs may include the presence of netting on the rind, a perfume aroma from the blossom end, a color shift, and a slight crack appearing at the base of the stem attachment. Some varieties will “slip” off the vine when ripe — this is the ideal time to harvest. Watermelons have different telltale signs: The bottom of the fruit will turn yellowish where it touches the ground when approaching full ripeness. A watermelon will also sound hollow sound when thumped with your knuckles. 

Yield per 50-foot row: 40 pounds of muskmelons

Soil Preparation

See “Cucumbers” for soil preparation information.

Propagation

Main season summer squash and zucchini are generally direct-seeded outdoors, though a round of transplants can be started indoors four weeks before the last frost for a jump on the season. Some gardeners transplant their vine crop seedlings and direct seed more on the same day to ensure a longer harvest season. Space hills (clusters of three to five plants) 3 to 5 feet apart.

If direct seeding, wait until soil reaches 60 to 65 degrees Fahrenheit. Squash and zucchini benefit from warm soil and even moisture and do well planted through black plastic. Put the plastic on the soil a week or two before planting to help warm the soil. Row covers can also be added at time of transplant for extra warmth as well as insect protection. 

Culture

If you did not use plastic mulch, apply a heavy organic mulch around the plants after the soil has warmed. Even moisture is essential. Side-dressing with well-rotted manure about four weeks after transplanting is beneficial. If using row cover, remove at flowering; cucurbits are not self-pollinating and require bees for pollination.

Common Problems 

See “Cucumbers” for common problems.

Harvest

Summer squash and zucchini should be harvested when small because they lose flavor and the texture is less desirable when large. Harvest daily, since ripening fruit draws energy from the plant at the expense of other, developing fruit.

Yield per 50-foot row: 60 pounds

Soil Preparation

See “Cucumbers” for soil preparation information.

Propagation

When sowing seeds, use cells that are 2 inches in diameter, minimum, and use a soilless mix that is on the dry side. Place sown flats in a warm place (80 to 95 degrees Fahrenheit) for germination. About three weeks after seeds are sown, they’re ready to be transplanted to the field. Space 12 inches apart in rows 6 feet apart for compact varieties and 12 feet apart for larger fruits. 

You can also direct seed squash, but seeds will not germinate in cool soil — wait until it reaches 60 to 65 degrees Fahrenheit. Since winter squash and pumpkins require a long growing season, seeds should be sown as soon as possible after the soil warms. If using black plastic, put the plastic on the soil a week or two before planting to help warm the soil. Row covers can also be added at time of transplant for extra warmth as well as insect protection. 

Culture

If you did not use plastic mulch, apply a heavy organic mulch around the plants after the soil has warmed. Even moisture is essential. Side-dressing with well-rotted manure about four weeks after transplanting is beneficial. Remove row cover, if using, at time of flowering; cucurbits are not self-pollinating and require bees for pollination.

Common Problems 

See “Cucumbers” for common problems.

Harvest

Winter squash should be allowed to mature to the point where the skin resists puncture by your fingernail. You can cure squash in the field for five to seven days, covering it at night if frost threatens; or you can cure it in a ventilated greenhouse at 80 to 90 degrees Fahrenheit for three to five days. Curing eliminates some of the moisture in the skin and toughens the skin. After curing, store winter squash at room temperature in a dry place.

Yield per 50-foot row: 80 pounds

Soil Preparation

Light, moderately fertile soil with good water-holding capacity is best for root crops. Never add fresh manure, since excess soil nitrogen will promote hairy roots. The pH should be 6.5, and the soil should have plenty of potassium, so wood ashes are often appropriate. Dig the soil deeply and remove small rocks, since they will impede growth and lead to misshapen roots.

Propagation

Carrots germinate slowly, and the soil must be kept moist during germination. Some gardeners sow quickly-germinating radishes in with carrots in order to mark the rows before the carrots germinate.

Carrots can be sown from early spring through mid-summer for a consistent crop. Choose storage varieties for fall harvest. Make a furrow in soil and sprinkle seed about 1 inch apart in a 2-inch band in rows spaced 16 to 24 inches apart; thin carrots to 1 to 2 inches (the width of your thumb is a handy measurement).

Culture

Weeding is essential. Carrots are slow to get started and are easily out-competed by weeds. Water during dry spells.

Common Problems

The larva of the carrot rust fly is a maggot that tunnels into carrots. The tunnels can be seen on the surface of the carrot and are rusty in color due to the maggot’s excrement — hence the name of the pest. Larvae feeding during the summer cause stunted plants that turn yellow, and larger larvae destroy the crop. Larvae in fall carrots may be small when the crop is harvested for storage and may go unnoticed, but they continue to develop into large larvae during storage. Controls for carrot rust fly are all cultural modifications. If feasible, rid the growing area of all hosts the year before growing carrots, and, in any fields that had hosts, plow deeply in the fall to bury overwintering pupae. Planting later than the end of May will avoid the first generation of egg-laying flies. Harvesting an early planting by mid-June will get carrots out before the larvae enter the taproot or grow large enough to be noticed. Covering the planting with floating row cover is the best control — especially if you have had repeated problems with the pest and know that it overwinters regularly in your area.

Harvest

Harvest when the roots are large enough to eat, since old roots lose their flavor and crack. Carrots can also be kept and harvested throughout the winter under a thick mulch of hay, but rodents may become a problem.

Yields per 50-foot row: 45 pounds

Soil Preparation

Light, moderately fertile soil with good water-holding capacity is best for root crops. Never add fresh manure, since excess soil nitrogen will promote hairy roots. The pH should be 6.5, and the soil should have plenty of potassium, so wood ashes are often appropriate. Dig the soil deeply and remove small rocks, since they will impede growth and lead to misshapen roots.

Propagation

Parsnips germinate slowly, and the soil must be kept moist during germination. Some gardeners sow quickly-germinating radishes in with parsnips in order to mark the rows before the parsnips germinate. 

Parsnips require a long season and should be sown directly in the garden in early to mid-spring. Sow seeds 1 inch apart in rows 18 to 24 inches apart; thin to 2 to 3 inches after emergence. 

Culture

Weeding is critical. Parsnips are slow to get started and are easily out-competed by weeds. Water during dry spells.

Parsnip foliage can cause a severe rash which may develop into blisters. As a precautionary measure, wear long sleeves/pants and gloves when working with parsnips on sunny days and wash skin immediately after contact.

Harvest

Harvest when the roots are large enough to eat, since old roots lose their flavor and crack. Parsnip flavor is enhanced by frost, and some say the best crop is harvested the spring following the planting year. A thick mulch of hay will protect the roots, and they can be pulled through the snow until the ground freezes. Digging them in the spring is a common tradition.

Yields per 50-foot row: 50 pounds

Soil Preparation

Light, moderately fertile soil with good water-holding capacity is best for root crops. Never add fresh manure, since excess soil nitrogen will promote hairy roots. The pH should be 6.5, and the soil should have plenty of potassium, so wood ashes are often appropriate. Dig the soil deeply and remove small rocks, since they will impede growth and lead to misshapen roots.

Propagation

Beets can be sown every 2 to 3 weeks throughout the growing season, starting in early spring, for a continuous supply. For roots, sow seeds in a furrow in the garden, about 1 per inch, and thin to one plant per 2 inches. Seeds can be sown more densely for beets greens and thinned to the same spacing for root production. Some growers also start beets in flats and transplant them into the garden. 

Culture

Keep beets well weeded and evenly watered. 

Harvest

Harvest when the roots are large enough to eat, since old roots lose their flavor and crack. 

Yield per 50-foot row: 35 pounds

Soil Preparation

Light, moderately fertile soil with good water-holding capacity is best for root crops. Never add fresh manure, since excess soil nitrogen will promote hairy roots. The pH should be 6.5, and the soil should have plenty of potassium, so wood ashes are often appropriate. Dig the soil deeply and remove small rocks, since they will impede growth and lead to misshapen roots.

Propagation

Radishes germinate very quickly and mature in three to six weeks depending on variety. Sow salad types every 2 to 3 weeks, starting in early spring, for continued harvest. Winter/storage radishes, such as daikon and watermelon radishes, are best planted in the late summer and early fall. 

Direct sow in garden furrows at a rate of 1 seed every inch in rows 1 foot apart.

Culture

Thin radishes to desired spacing based on varietal requirements. Keep weeded. Water during dry spells.

Common Problems 

Flea beetles can damage the foliage, and may reduce yields if pest pressure is great. To reduce and delay flea beetle invasion of spring crops, move them as far away as possible from the fields that were previously used for Brassica crops. Flea beetles overwinter in field borders near last year’s crop. Planting the same crop close by to where it was last year ensures a high population in the spring. The same could be true if you have fields full of mustard weeds, or move to a field that was seeded to a Brassica cover crop the previous year. One of the best ways to protect Brassica crops from flea beetles is to place a floating row cover, or exclusion netting, over the bed or row. It is critical to seal the edges immediately after seeding or transplanting, because Brassica seeds germinate quickly and beetles rapidly find the cotyledons. Flea beetles can fit through extremely tiny cracks. Edges of the cover must be sealed on all sides using soil, plastic bags filled with soil, or some other method.

Harvest

Harvest the roots promptly when they are large enough to eat to avoid pithiness. 

Yield per 50-foot row: 40 dozen

Soil Preparation

Neither turnips or rutabagas require high levels of fertility. They do well in loose, humus-rich, well-drained loam with a pH between 5.5 and 7.0; heavy clay soils can cause root branching. Turn manure into the planting area the previous fall, or add well-rotted manure or compost in the spring.

Phosphorous concentrations need to be adequate for root growth, and like other root crops, turnips and rutabagas need trace amounts of boron. If needed, you can amend your soil with a good compost or add a small amount of agricultural borax or soil amendment containing boron. 

Propagation

Rutabagas and turnips have similar planting needs. Turnips can be planted as a spring or fall crop, and salad varieties can be sown every two to three weeks throughout the season. Sow spring crops as soon as the ground can be worked; sow fall crops in midsummer.

Rutabagas need at least 90 days to mature, and seeds should be sown at least three months before fall frost and harvest. 

Sow seeds 1/4 to 1/2 inch deep in a row or bed, spacing seeds about 1 inch apart. If the soil is dry, flood the furrows before seeding. Rows should be 15 inches apart for turnips and 18 inches apart for rutabagas.

Culture

The seed will germinate in three to seven days. Once plants are 4 to 6 inches high, thin them to 6 to 8 inches apart to ensure ample room for root development. Salad turnips need only be thinned to 2 inches or so.

Keep weeded.

Common Problems

In Maine, planting rutabagas in mid-June may help to avoid the early flea beetles. See “Radishes” for more information on this pest. 

Harvest

Harvest when the roots are large enough to eat. Turnips mature more quickly than rutabagas, but do not store as well.  Turnips make a great summer crop — and will provide ample fresh greens in addition to roots. Rutabagas store well in the root cellar and will keep into late spring.

Soil Preparation 

Sweet corn is a very heavy feeder and requires full sunlight. Fertilize the soil before planting, because once stunted, corn rarely recovers. Work a 2-inch-deep layer of well-rotted manure, 5 pounds per 100 square feet of phosphate rock phosphate and 5 pounds per 100 square feet of greensand into the soil. Soil tests will indicate if less rock powder is needed in future years. A pH of 6.0 to 6.8 is recommended.

Propagation

Corn is most often planted directly in the garden, 6 inches apart in rows that are 3 feet apart. Thin plants to 12 to 15 inches apart. A supply of fresh corn can be obtained by following this schedule: Plant an early variety and midseason variety about two weeks before the last frost; when the early variety has produced four leaves, sow another planting of the midseason variety plus a late season variety; one week later plant some more late-season corn. For an extra-early harvest, some people also start corn seedlings indoors about two weeks ahead of time and transplant those seedlings at the same time that they direct seed their first crop.

Corn is wind pollinated, and pollen released from the tassel must land on every strand of silk in order to pollinate every kernel in the ear and avoid “skips.” So corn is best planted in blocks of at least four rows to ensure good pollination.

Culture

Corn is a heavy feeder, so prepare a fertile soil as noted under “Soil Preparation.” Sidedress with some manure when plants are 5 to 6 inches tall. Early weeding is essential. Hilling soil around the base of plants will keep down weeds and offer additional support. After the tassels are produced, corn needs 1 inch of water per week. Do not remove suckers (side stalks growing out from the base of plants), as this may injure the plants.

Common Problems

Corn earworms and the European corn borer are the most common pests during the midsummer. The earworm does not overwinter in Maine, but adults migrate from the South by midsummer. The female moth lays eggs on the silk, and the larvae work their way to the tip of the ear and devour the kernels. Corn varieties with tight husks are more resistant. A few drops of mineral oil squirted into the ear through the silk channel may suffocate the worm. Bacillus thuringiensis (Bt) squirted in the channel may work, especially with the oil. At harvest, gardeners can also simply break off the tips of ears of corn that have earworms.

The borer overwinters in debris from the previous year’s corn, especially the lower end of the stalk. Destroying the stalks, fall plowing, a cold winter or early spring plowing will reduce populations. Early signs of damage appear as shot holes in the young leaves as they unfold out of the whorl where the caterpillar is feeding. As the caterpillar grows it will bore into the stalk and you can find holes where it enters or broken tassels where the stalk is weakened. Bt will work on the young larvae if you can get it down into the whorl at the right time. A granular Bt product is on the market, but the best controls are crop rotation and destroying last year’s stalks, unless you are surrounded by other fields of corn.

Harvest

Harvest about three weeks after silks emerge at the milk stage — when pierced kernels exude a white liquid — and when the tip of the ear feels full. Sweet corn is best harvested early in the morning, when temperatures are cool and moisture is high. 

Peak quality occurs right after picking. Some gardeners say to get the water boiling before you walk out to the garden to harvest the corn. Many newer varieties of sweet corn hold their sweetness longer than older varieties.

Yield per 50-foot row: 5 dozen ears

Soil Preparation 

Sweet potatoes are adaptable and will grow in poor soils, but yield far more in a well-drained, slightly acid, fertile loam. Heavy clay impedes root growth, so lighten heavy soils with organic matter.

Prepare a raised bed that is at least 15 inches wide by turning in a 6-inch layer of compost. You can turn in manure or green manure in the fall.  Avoid heavy applications of nitrogen, as well as fresh manure — which may blacken sweet potato skin. 

Propagation

Choose a variety that is suited to be grown in the North, such as Georgia Jet or Beauregard. Order slips — rooted sections of the sweet potato vine that are about 1 foot long — from a supplier or you can try to propagate your own. 

Once the soil is at least 65 degrees Fahrenheit, transplant your sweet potato slips 15 inches apart in the prepared beds. Plastic mulch can be used to warm the soil ahead of time. 

Culture

You can cover the beds with row cover for increased heat (the more 100-degree days, the better the yield); plants should not be exposed to temperatures below 50 to 55 degrees Fahrenheit.

Make sure the plants do not go more than a week without water. Ideally, you should provide each plant with 1 gallon of warm water when the soil is dry.

Harvest

Sweet potatoes continue growing larger until the soil cools to 50 degrees or below. If grown under row covers, your soil should cool by mid- to late September. Harvest sweet potatoes carefully to avoid bruising. Cure sweet potatoes by spreading them in a very warm place — 85 to 90 degrees — for one week, or at 75 to 85 degrees for two weeks. Once cured, sweet potatoes should be stored at 55 degrees.