University of Maryland Extension

Summer Squash

comparing male and female squash flowers

Summer squashes (Curcubita pepo) are warm-season plants that do not grow well until soil and air temperatures exceed 60°F.  They are harvested when immature and the rind is still tender and edible. 

In addition to describing the time of planting, "summer squash" refers to their short storage life, unlike that of winter squashes. Summer squash grows on non-vining bushes. There are many varieties having different fruit shapes and colors. The three main types are:

  • yellow straight neck or crooked neck;
  • white, saucer-shaped, scallop or patty pan; and
  • oblong, green, gray, or gold zucchini.

Planting

Plant 2 to 3 seeds every 2 ft. to 3 ft. in the row after danger of frost has passed and soil has warmed. You can also plant transplants by sowing seed indoors in 3-inch diameter containers 3 weeks before planting time. Seed or transplants can be planted through black plastic to hasten maturity. After seedlings emerge, cut excess plants with scissors, leaving the single strongest plant.  If using transplants, handle them gently and disturb the root system as little as possible. Plant a second crop between July 1 and 15.

Cultivation

  • Fertilizing - Side-dress these medium feeders with ¼ lb. 10-10-10 per 10 feet of row 4 weeks after blossoming begins. Soil containing plenty of compost or well-rotted manure is ideal, but good crops can also grow in average soils that have been adequately fertilized.
  • Watering - Water deeply and regularly at the base of each plant, especially during hot, dry weather and once the first fruits start to form.
  • Weeding - Remove all young weed seedlings by hand or with a hoe and use a mulch around plants to keep weed seeds from germinating.
  • Special directions - Many squashes will produce male flowers for 1 to 2 weeks before the first female flower is observed. This is a normal growth habit and varies with cultivars. For a squash flower to develop into a fruit, pollen must be carried by bees from male flowers, on the same plant or on different plants, to the female flower (the one with the tiny squash). Poor fruit-set is common during rainy weather when bees are inactive. Avoid using pesticides during the bloom period.

Common Problems

Harvesting

Harvest when the squash is still immature, only about 6- to 8-inches long and 1½ to 2 inches in diameter for elongated types; 3 to 4 inches in diameter for patty pan types; and 4 to 7 inches long for yellow crooked neck. If the rind is too hard to be marked by the thumbnail, it is over-mature. Remove old fruit to allow new fruit to develop. Check plants daily once they begin to bear fruit.

Storage and Preservation

Will keep for 5 to 14 days in cool (32°- 50°F), moist (90% Relative Humidity) conditions.

Nutrition

Good source of vitamin C, manganese, potassium, and vitamin B6 (pyridoxine)

Preparation and Use

Wash, trim ends and cut or slice into pieces; can be baked, sautéed, broiled, grilled.

Print: (PDF) GE 125 Summer Squash

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