How To Grow An Organic Garden

Growing Organic Winter Squash - Best Practices


Winter Squash could be considered a deceptive term considering it needs warm summer conditions to thrive.

There are many types of winter squash including butternut, acorn, hubbard, pumpkins, calabaza, delicata, kabocha, spaghetti, and cusha are 9 of the more common varieties, although this list is not all-inclusive.

Winter squash is different from summer squash in that it is harvested and eaten at full maturity while summer squash (such as zucchini) is best picked young. Unlike summer squash, winter squash has long-term storage capabilities (hence the name ‘winter’ squash).


Winter squash need 75-120 days of frost free outdoor weather to bring fruit to full maturity. Seeds can be planted outdoors a week after the last frost date or when soil temperatures maintain a steady 60F.


Squash needs full sun in rich healthy soil. Squash are heavy feeders. These plants thrive in soil rich in organic compost and well-rotted manure.

Mix adequate amounts of the aforementioned amendments into your soil, but be careful not to pass recommended nitrogen (N) levels; excessive nitrogen levels will give your plants great foliage but minimal fruit. pH level 6.0-6.5


Choosing a disease resistant squash seed is the first step for a successful organic crop and harvest. Winter squash seeds require warmer temperatures for germination of between 70F-95F, with the optimum temperature being 95F; squash seeds last up to 4 years.

GETTING STARTED INDOORS (and transplanting)

If a cooler summer is predicted or you live in an area with a short growing season, give your squash a head start indoors. Squash has a very delicate root system; if disturbed the plant will be stunted or die; to minimize risk plant in individual 4” pots (preferably peat pots).

Plant your indoor starts 1 month before the last frost date, 2-3 seeds per individual pot, clipping the weaker seedlings once they develop their first 2 true leaves.

Before transplanting seedlings outdoors, harden off (take outdoors during the daytime) for 1 week; bring them in towards evening, as the seedlings are sensitive to cold. Hot caps will protect and keep the plant warm until warmer weather arrives.

PLANTING/GROWING (Planting seeds directly into the garden)

We recommend hill planting for your winter squash. Planting on mounded soil will provide added warmth and good drainage for your plants.

To form each hill, first dig a hole 1’ deep and fill with compost. Mound soil mixed with a shovel full of well aged manure forming a 1’ high and 2’-3’ wide hill. Space hills at least 5’ apart to allow room for sprawling vines which can grow 10’-20’.

Sow 6 seeds in a circle 1” deep on the top of each hill, but hold off thinning until the plants are well established. When you thin your plants, leave the three strongest plants.

To give your seedlings an early boost, cover your planting area with plastic 1-2 weeks before transplanting.

Squash is very susceptible to disease, especially when exposed to too much rain. If you are having an abnormally wet year, or your area is prone to rain, consider building a cold frame to give your squash plants some shelter during the rainy season.

If garden space is limited, provide a framework to climb. Tie 3 poles together at the top and spread the legs out to form a tripod. Secure the poles by burying the legs 6-12” into the soil; a trellis is also a good support system.

Weeds are tough competition for growing squash, especially when they are young. Suppress the competition by shallow cultivation or hand weeding before the squash plants begin to sprawl.

Once the vines begin to spread outward, add a thick layer of mulch (such as straw, hay, or leaves). This will also keep the fruit from having direct contact with the soil and minimize rot.

Bees are necessary for pollinating winter squash. Here on our farm, getting our plants pollinated is never a problem since our neighbor raises honey bees. If you are uncertain of the bee population and want to ensure pollination you can hand pollinate your squash flowers.

To do this, simply pluck the male flower and remove all petals; whirl it around inside the female flower so that the male stamen transfers pollen to the female pistil.

When the first fruits appear, fertilize your plants with compost tea or side-dress with composted manure.

By mid-summer, winter squash will have developed all the fruit that will have time to mature. Remove remaining flowers so the plant can put all its energy into ripening the existing fruit.


Keep seedlings moist throughout the growing season. Overhead watering creates the same environment for disease as excessive rain does. Wet foliage is a breeding ground for diseases such as powdery mildew, downy mildew and black rot.

Using drip irrigation will help keep the foliage dry and the roots moist. When rain does occur, avoid spreading mildew by not handling the plants when wet. Squash does require high levels of water, but avoid standing water.


It has also been observed that when growing squash, pests are effectively reduced by the presence of nasturtiums, oregano, marigolds, mints, bee balm, catnip, tansy, and radish.

Some backyard gardeners claim that planting potatoes amongst squash plants helps to detour the squash bug even though potatoes are considered by many a “bad companion.”

Potatoes generally are not recommended to plant next to squash because they have different soil requirements.

Squash needs composted manure to grow, but manure causes scabs in potatoes. This is easily solved by hill planting and concentrating your amendments to plant type. Crop rotation is also strongly recommended.


Harvest squash before the first heavy frosts. Light to medium frost will increase sugar content in the fruit and cause the foliage to die off, making harvesting easier. Squash, when ripe, will change to a deep, solid color, different from what it was during the growing stage.

To test for ripeness, try to push your fingernail through the outer skin. A ripe fruit will have a tough rind making this difficult to do. Squash will be ready for harvest when the outer shell becomes hard enough that your finger nail cannot easily penetrate the rind.

Leave two inches of stem on the squash when harvesting to prolong its shelf life.


To properly cure squash after the harvest, place your harvested squash in an area that remains 75F-85F for 2 weeks. Next transfer squash to a location for the winter that maintains a temperature around 50F and humidity of 50-75%.

Fruits that have been damaged by frost, bruised, or did not fully ripen will not have a long storage life and should be used immediately.


One organic solution to prevent mold is the application of baking soda as a fungicide.

Cornell University successfully sprayed pumpkin foliage with a mixer of baking soda and horticulture oil at 0.5% per gallon.

Some less definitive studies suggest that simply an ounce of baking soda with a gallon of water is effective on plant leaves and when used at this ratio and won’t harm plant or fruit.

Give your plants a boost with a liquid organic leaf spray every two weeks to help build strong immunity against pest and disease, as well as to increase the size and sweetness.

Squash Beetle, squash vine borer, cucumber beetle, and aphids are all risks to winter squash. A tightly secured row cover over the young plants will repel these bugs, although row covers must be removed when flowers appear so pollination can take place.

To further fight pests you may want to use organics such as diatomaceous earth, sabadilla, or neem oil, though these can tend to be expensive and the effect may not be worth the expense.

If you have a long growing season you may be able disrupt pests by staggered plantings.