How to Grow Winter Squash Plants: The Complete Guide (2024)

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Squash love a warm, sunny, and sheltered spot—ideal conditions for good pollination and proper fruit development. The plants are hungry feeders and need rich, fertilesoil.

Plant squash in a location with full sun and lots of space for sprawling vines. Most full-size winter squash varieties need 50 to 100 square feet to spread.Soil must be well-fed and moist (not soggy), and well-draining.Mix aged manure and/or compost (about 50% native soil to organic matter) deep into the soil a couple of weeks beforeplanting.

Methods of PlantingSquash

• Direct-sow (i.e., plant seeds directly in the ground) when all danger of frost has passed and the soil is at least 60°F, preferably 70°F. Squash is very sensitive to thecold.
• If you have a short growing season, start seeds in peat pots 2 to 4 weeks before yourlastspring frost date. Squash seedlings do not always transplant well, so handle the rootsgently.

Most garden stores and nurseries also sell ready-to-plant seedlings—handy if you only want to grow a fewplants.

Set your plants out after all danger of frost has passed. Start to acclimatize them to outside conditions two weeks beforehand. Leave them out during the day for increasingly longer periods and then, from the second week, overnight in a sheltered position. Plant trailing varieties up to five feet (1.5m) apart and bush types about three feet (90cm) apart. Thoroughly water plants into position to settle the soil around therootball.

How to PlantSquash

• If you plan to grow only a few plants, use 2 to 3 tablespoons of a balanced (10-10-10) fertilizer for each hill. Scatter the fertilizer evenly over a 2-foot by 2-foot area. Work it into the top 3 to 4 inches of soil. Or, for a larger garden area, add 2 to 3 pounds of balanced fertilizer for each 100 squarefeet.
• Sow seeds inlevel ground 1 inch deep with seeds 2to 3 feet apart. Or, sow 3 to 4 seeds close together in small mounds (or hills; the soil is warmer off the ground) in rows 3 to 6 feetapart.
• Consider planting a few squash seeds in midsummer to avoid problems from squash vine borers and other early-season pests anddiseases.
• The seeds should germinate in about a week with the right soil temperature (70ºF / 21°C ormore).
• If necessary, use row covers or frame protection in cold climates for the first few weeks ofspring.
• Use row covers to prevent insect problems early in the season. Remember to remove covers before flowering to allow pollination byinsects.

See this helpful video on how to sowseeds.

• Mulch to discourage weeds, retain moisture, and protect shallow roots. Mulch around plants with organic matter to help lock in valuable soil moisture and contribute additionalnutrients.
• Water thoroughly, frequently, and consistently, with at least 1 inch per week. Water at soil level and try to keep leaves and fruit dry. Dampness will make root rot and other diseases morelikely.
• Keep plants well watered to encourage rapid growth. You can make watering easier by sinking six-inch (15cm) pots alongside plants. The pots will hold onto the water and deliver it through the drainage holes directly where it’s needed, at theroots.
• When weeding around squash plants, do not over-cultivate, or the squash’s shallow roots may bedamaged.

ThinningSeedlings

• When seedlings inrows are 2 to 3 inches tall, thin to one plant every 18 to 36 inches by snipping off unwanted plants without disturbing the roots of the remainingones.
• When seedlings inhills are 2 to 3 inches tall, thin to 2 to 3 plants per hill by snipping off unwanted plants without disturbing the roots of the remainingones

Fertilizing

• When the first blooms appear, scratch about2 tablespoons of all-purposefertilizer around each hill.Or, if growing squash in rows, side-dress. This give plants a boost as they try to produce fruit or blooms. Do not let the fertilizer touch the plants. Water the plants afterfertilizing.
• Once vegetables or flowers start growing and producing buds, you can scratch a small amount of all-purpose organic fertilizer into the soil around the base of the plant and waterin.

Flowering andFruiting

• Poor pollination can result in squash flowers that do not bear fruit, or that bear small fruit. Pollinator activity is reduced by any chemicals,poor weather at bloom time, and lack of habitat. To attract more bees, try placing a bee house in your garden or plant pollinator flowersnearby.
• If your first flowers aren’t forming fruits, that’s normal!Squash plants have separate male and female flowers. Males appear first on long thin stalks. Female flowers follow with an immature fruit at the bottom. To fruit, pollen from male flowers must be transferred to the female flower by bees. Or, the gardener can help manually with a cotton swab or paintbrush.See our article on how tohand pollinate your squash blossomsforbetteryields.

Pruning

Although in many cases winter squash vines do not need pruning, there are instances where it might be necessary or desired. Pruning can reduce the number of squashes that grow, but helps the vine to put its energy into healthy growth and largerfruit.

1. At any time, prune out dead, damaged, or diseased leaves or shoots. This applies to bush types,too.
2. Whether your squash has a bush or vining habit, check for overcrowding and thin out a few lateral (non-main) stems or some lower (especially those touching the ground) or overlapping leaves to allow for better air circulation, which can help to prevent disease such as powdery mildew, reduce hiding areas for insect pests, and help pollinators to find the flowers. (A baby squash that has not been successfully pollinated will grow just a few inches and then rot.) Overcrowding can also cause weakened growth. Be sure, though, to leave enough leaves for the plant to make food for itself; do not prune more than 1/3 of theplant.
3. Some vining varieties may take over the garden, growing as long as 10 to 20 feet. If you are short on space, a little pruning can help keep these vines under control. Or, you might consider growing them vertically or selecting a bush type, which does not have a sprawlinghabit.

Various gardeners have favorite methods for pruning their plants, while others prefer to essentially leave things alone, but here are some general guidelines:

• A vining winter squash plant has one or more main stems, each with secondary vines growing off it; in addition, tertiary vines may grow off the secondaryvines.
• For vining squash types, many gardeners remove several nonfruiting secondary and all tertiary vines during the growing season. If you use this method, cut them back to their base, where they are attached to the main stem (leave about ½ to 1 inch of lateral stem, being careful not to injure the main stem). Again, do not remove more than 1/3 of the growth of the plant at any onetime.
• For fruiting secondary vines, wait until they are at least 10 or so feet long (depending on variety) and have about 3 to 5 fruit developing on them, then you can cut them back to 1 to 3 leaf nodes beyond the last fruit (toward the tip end). This will help the plant to focus on developing the remaining fruit on that vine rather than on growing the vinelonger.
• Do not prune the main vines until toward the end of the season, at which point you might clip the growing tips off (as you did earlier to the secondary vines) to promote the ripening of existing fruit instead of more flowering. (Any flowers that form late in the season would produce fruit that might not mature in time before the end of the growingseason.)

In general, the best time to prune is in the morning, when it is cooler, which allows the plant to recover before the end of the day. Alternatively, prune in the cool of earlyevening.

When pruning, be sure to disinfect your pruning tools before each cut, to help prevent spreading disease. It helps to make sure that they are sharp, too. Learn how to sharpen your gardening tools.

Discard the pruned plant debris away from the plants. If diseased stems or leaves are removed, do not compost them, as some diseases may survive in the finishedcompost.

• ‘Waltham Butternut’:A large, tan fruit; this butternut squash is sweet and thin-skinned; harvest when it’s on the smaller side; flavor improves withstorage
• ‘Honeybaby’or ‘Honeynut’ butternut squash plants are compact and ideal for small spaces, raised beds, or containers. Expect about 8 small squash per plant. They’ll weigh a quarter to a half pound and perfect for steaming orbaking.
• ‘Butterscotch’ butternut squash produces 1 to 2-pound fruits on short vines. The sweet flesh is rich and smooth. Each plant yields 3 to 4 fruits and the plant is resistant to powderymildew.
• Blue Hubbard squash is an heirloom known for its huge size, blue-gray color, and very hard skin. The flesh inside is orange, flavorful and smooth. It is great for pies and soups and stores well. Give this variety plenty of room togrow.
• ‘Buttercup’: A round fruit with long vine, Buttercup has deep, brightorange flesh, a dark green inedible rind, and flat top.This heirloom has asweet, nuttyflavor.
• ‘Delicata’:This bush type squash almost looks like a summer squash. It’s very moist and even good raw. Plus, its thin skin is edible, too. Delicata is also tolerant of powderymildew.
• ‘Tuffy’:An acorn type of squash, expect five or six fruit per plant. Acorn squash is bowl-shaped and has a nutty flavor andmore fiborous texture than somesquash.
• ‘Sugaretti’ spaghetti squash has eye-catching striped fruits. Each medium-sized squash grows up to 10 inches long and has a sweet nutty flavor. The plants are compact and are resistant to powdery mildew. Bake the squash and use the flesh as a pastasubstitute.
• ‘Sunshine’:An award-winningkabocha squash with orange-red skin and bright orange flesh. The compact vine yields about 3 to 4-pound fruit that have a round, flattened shape. The flesh has a sweet nutty flavor and creamy texture. The fruits can be stored formonths.

→See more pictures of different types of squash.

Winter squash and pumpkins are generally ready to be harvestedin early- to mid-autumn, usually late September throughOctober.

• Unlike summer squash, which is harvested when tender and a bit immature, harvest winter squash when it is fully mature. The vine leaves die back and turn brown, the stems dry out and get tough,and the rind is deep in color and hard.If you can pierce the skin with your fingernail, it is notmature.
• Harvest on a dry day after the vines have diedback.
• Leave an inch or two of stem on winter squashes when harvestingthem.
• Cut the squash off the vine carefully with a sharp knife or pruners; do not tear, as you could break the fruit stem or thevines.
• Never carry the squash by their stem; if the stem breaks off, this exposes the skin toinfection.

Once you harvest, don’t forget to clean up the old squash vines to avoid disease! Addvines to the compost pile if you have one. They’ll break down, andyou can work the compost into the soil before the next plantingseason.

How to Cure WinterSquash

Winter squash must be cured before storage. This process helps to dry off excess moisture and to harden the skin, sealing out fungi and bacteria, which allows the squash to be keptlonger.

Cut either side of the stem to leave a T-shaped stub. Avoid the temptation to use the stem as a handle, as it could detach from the fruit and serve as an entry point to rot. Move fruits to a warm, dry, and sunny spot tocure.

If theweather is dry, just leave your squash on the vine and let them cure outside in the sunshine. If it’s wet or turning colder, bring the squashinside and put them somewhere warm and dry, such as a slatted greenhouse bench or a sunnywindow.

Curing hardens the skin and is ready for storage. If it’s already turned cold and damp outside, cure fruits in a greenhouse or on a sunny windowsill. Winter squash and pumpkins will be stored for up to six months at roomtemperature.

How to Store WinterSquash

Before storing winter squash, dip it into or wash with a low-concentration bleach rinse (1/2 cup bleach to 5 cups water) to sanitize the skin and eliminate bacteria. Air-dry thefruit.

Store in a cool (40° to 50°F), dry, dark place with good circulation. Many varieties of squash will last most of the winter. Note: Acorn will not keep for more than a few weeks. Occasionally rotate and look for signs of rot. Remove any squash that shows signs ofdecay.

Try to save some seeds if you growheirloom varieties (not hybrids) to plant next year. Wash and dry the seeds. Store in an airtight jar in a cool, darkplace.

Catherine Boeckmann