Squash and Zucchini

Planting, Growing, and Harvesting Squash and Zucchini

Zucchini

Squash, especially zucchini, is a prolific vegetable! Easy to grow, each plant will produce several squash a day during peak season. Make sure you harvest summer squash when tender and still immature!

There are many varieties of summer squash to choose from:

  • Summer squash including zucchini (Cucurbita pepo)
  • True winter squash (C. pepo)
  • Acorn squash, delicata, spaghetti squash
  • Butternut squash (C. moschata)

The main difference between winter and summer squash varieties is their harvest time; the longer growing period gives winter squash a tougher, inedible skin.

Squash is very susceptible to frost and heat damage so you do want to pick it all before the first fall frosts arrive.

With its bumper crops, you usually only need a plant or two for a bumper crop—and you may still find yourself giving zucchini away to neighbors or baking lots of zucchini bread!

Planting

  • If you wish to start seeds indoors due to a short gardening season, sow 2 to 4 weeks before last spring frost in peat pots. (See local frost dates.) However, we recommend direct-seeding for squash because they do not always transplant well. If you do transplant, be very gentle with the roots.
  • If you wish to get an early start, it may be better to warm the soil with black plastic mulch once the soil has been prepared in early spring.
  • The soil needs to be warm (at least 60º at a two-inch depth), so plant summer squash after spring (cool-season) crops, like peas, lettuce, and spinach—about one week after the last spring frost to midsummer.
  • In fact, waiting to plant a few seeds in midsummer will help avoid problems from squash vine borers and other pests and diseases common earlier in the season.
  • The outside planting site needs to receive full sun; the soil should be moist and well-drained, but not soggy.
  • Squash plants are heavy feeders. Work compost and plenty of organic matter into the soil before planting for a rich soil base. (Learn more about soil amendments and preparing soil for planting.)
  • To germinate outside, use cloche or frame protection in cold climates for the first few weeks. 
  • Plant seeds about one-inch deep and 2 to 3 feet apart in a traditional garden bed.
  • Alternatively, plant as a “hill” of 3 or 4 seeds sown close together on a small mound; this is helpful in northern climates, as the soil is warmer off the ground. Allow 5 to 6 feet between hills.
  • Most summer squashes now come in bush varieties, which take up less space, but winter squash is a vine plant and needs more space. Bush varieties will need to be thinned in early stages of development to about 8 to 12 inches apart.

Care

  • Mulch plants to protect shallow roots, discourage weeds, and retain moisture.
  • When the first blooms appear, apply a small amount of fertilizer as a side dress application.
  • For all type of squash, frequent and consistent watering is recommended. Water most diligently when fruits form and throughout their growth period.
  • Water deeply once a week, applying at least one inch of water. Do not water shallowly; the soil needs to be moist 4 inches down.
  • After harvest begins, fertilize occasionally for vigorous growth and lots of fruits.
  • If your fruits are misshapen, they might not have received enough water or fertilization.

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Pests/Diseases

  • There are a couple of challenging pests, especially the squash vine borer and the squash bug. The best solution is to get ahead of them before they arrive.
  • If your zucchini blooms flowers but never bears actual zucchini, or it bears fruit that stops growing when it’s very small, then it’s a pollination issue. Most squashes have separate male and female flowers on the same plant. To produce fruit, pollen from male flowers must be physically transferred to the female flowers by bees. If you do not have enough bees, you can manually pollinate with a Q-tip—or, add nearby plants that attract bees!
  • Cucumber Beetle
  • Blossom-End Rot: If the blossom ends of your squash turn black and rot, then your squash have blossom-end rot. This condition is caused by uneven soil moisture levels, often wide fluctuations between wet and dry soil. It can also be caused by calcium levels. To correct the problem, water deeply and apply a thick mulch over the soil surface to keep evaporation at a minimum. Keep the soil evenly moist like a wrung out sponge, not wet and not completely dried out.
  • Stink Bug: If your squash looks distorted with dippled area, the stink bugs overwintered in your yard. You need to spray or dust with approved insecticides and hand pick in the morning. Clean up nearby weeds and garden debris at the end of the season to avoid this problem.
  • Aphids

Harvest/Storage

  • Harvest summer squash when small and tender for best flavor. Most varieties average 60 days to maturity, and are ready as soon as a week after flowering.
  • Check plants everyday for new produce.
  • Cut the gourds off the vine rather than breaking them off.
  • Fresh summer squash can be stored in the refrigerator for up to ten days.
  • Harvest winter squash when rind is hard and deep in color, usually late September through October.
  • Winter squash can be stored in a cool, dark place until needed. It will last for most of the winter. If you have a cool bedroom, stashing them under the bed works well. They like a temperature of about 50 to 65 degrees F.
  • Freezing Summer squash: Wash it, cut off the ends, and slice or cube the squash. Blanch for three minutes, then immediately immerse in cold water and drain. Pack in freezer containers and freeze.
  • Freezing Winter squash: Cook as you normally would, then mash. Pack in freezer containers. Learn more tips for freezing zucchini.
  • Pull up those vines and compost them after you’ve picked everything or after a frost has killed them. Then till the soil to stir up the insects a bit.

Recommended Varieties

Wit & Wisdom

  • Squash flowers make a tasty treat when fried in a light batter.
  • Pumpkins and other squashes are nutritional powerhouses! Learn more about squash’s health benefits!

Recipes

Cooking Notes

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Botanical Name: 

Cucurbita

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Sun Exposure: 

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