Hardiness: Zones 3 and warmer
Light: Full sun in a site with good air circulation
Soil: Not fussy, grow in almost any type of soil that drains well; pH 5.5 to 6.8
Water: Regular water will increase yield, keep soil evenly moist
- Bushy cultivars: 3 to 4 plants per hill, in hills 18 to 24 inches (45 to 60 cm) apart.
- Vining types: 3 to 4 plants per hill, in hills up to 4 feet (1.2 m) apart.
Harvest: Pick at any size, but smaller is better. For best flavor pick Zucchini: 4 to 8 inches (10 to 20 cm); Yellow Squash: 4 to 5 inches (10 to 13 cm); Pattypan: 3 to 4 inches (7.5 to 10 cm) in diameter.
Comments: Squash are among the easiest vegetable crops to grow. Fast-growing summer squash include crooknecks, zucchini, and pattypan also called scallop. All are notoriously productive, so keep in mind what kind of squash your family likes to eat. Don’t plant entire seed packets of summer squash or you will have more squash then you know what to do with. Instead, plant only a few seeds, or transplants (if you choose to buy seedlings), of a few different kinds so you get a variety. They are all easy to grow, and if you’ve ever grown zucchini, then you can grow other types easily as well.
Squash are generally separated into three categories: summer squash, winter squash, and pumpkins. The difference between them all is really just based on how they are used. Summer squash are harvested when young and tender, while winter squash are harvested when hard and ripe. Pumpkins are really just winter squash, but have a distinctive pumpkin shape.
Planting Site: Plant in full sun in an area that has good air circulation. Squash grow best in moderately rich soil, but for best results, plant them in hills enriched with compost or lots of good organic matter like well-rotted manure.
Planting & Growing Guidelines: Squash grow best in warm soil. Sow seeds 2 weeks after the last expected spring frost, or when soil temperatures reach 60° F (16° C). Plant seeds 1 to 2 inches (2.5 to 5 cm) deep, in predampened hills, for bushy cultivars: plant 3 to 4 plants per hill, in hills 18 to 24 inches (45 to 60 cm) apart. For vining types: plant 3 to 4 plants per hill, in hills up to 4 feet (1.2 m) apart.
You can use the same spacing when planting out seedlings or transplants. A good trick when planting seedlings is to hill the soil up around the stem if it is more than 1 inch (2.5 cm) from the soil line to the first set of leaves. This is one time it’s OK to mound soil up around a plant’s stem, it won’t rot, and a stronger healthier root system will develop. If you have had problems in the past, cover the seedlings with row covers to protect them from squash bugs and cucumber beetles.
Summer squash can be planted until 8 weeks before the first expected fall frost. Cultivars with long vines can be trained up a trellis or fence if the fruits are not allowed to get too heavy, so harvest when the fruits are small and ideal size. Squash need regular water to keep the fruit producing, and can be grown without mulch, except in very dry climates, since the leaves are large enough to shade the soil on their own.
Squash can be grown in containers, just use the compact, bushy types. Feed the plants every three weeks with a good balanced water soluble fertilizer like a 5-5-5 or a 10-10-10. Hand pollinate to ensure fruit set (see the Common Problems Section below for instructions how to do this).
Fertilizing: Make sure the soil has already had lot of good compost and organic matter worked in. Lightly broadcast some 10-10-10 over the area, till in, and then plant transplants or sow seeds. When the plants just start to vine, side-dress with 1 tablespoon (15 ml) per plant of 5-10-10, or one large handful of good compost which generally equals the same. Sprinkle around the base of the plant, but not up against the stem, and water in.
Pest and Disease Prevention: Use row covers to protect young squash plants from cucumber beetles, and squash bugs that can carry and spread bacterial wilt, a common disease that causes plants to wilt and die suddenly. Remove the covers when the plants begin to flower. Radishes or basil interplanted with squash helps repel beetles and squash bugs. Don’t plant where squash or its relatives, such as melon and cucumber, have grown the previous year. Provide good air circulation to avoid mildew. If plants do develop mildew, spray the foliage thoroughly with a mild baking soda solution of (1 teaspoon (5 ml) per quart (liter) of water). To reduce the chance of many squash diseases, plant resistant cultivars.
Common Problems: Fruit that turns black and rots before reaching picking size has not been pollinated. This often happens early in the season before male flowers appear, or in cool weather when pollinating insects are not as active. Squash also won�t pollinate successfully in temperatures above 90° F (32° C). Many squash produce only male flowers at first, followed by a mixture of male and female flowers a week or so later. If female flowers are opening and withering without setting fruit, they may not be getting enough pollen. If bees are low in your area, you can pollinate the flowers yourself. Simply pick a male flower, and place it over a female one and tap it to release the pollen. To see an example of this read the “Squash and Pumpkin Section” in the “How to Maintain a Vegetable Garden” article listed in next Helpful Articles. Keep in mind however, poor pollination is seldom a problem if you have four or more plants flowering at the same time.
Days to Maturity: 45 to 50 frost-free days depending upon the cultivar grown.
Harvest and Storage: Harvest frequently to encourage more fruiting, by cutting the fruits with 1 inch (2.5 cm) of stem attached. Harvest every day or so, because squash deteriorates with age. Pick at any size, but smaller is better. For best flavor pick Zucchini: 4 to 8 inches (10 to 20 cm); Yellow Squash: 4 to 5 inches (10 to 13 cm); Pattypan: 3 to 4 inches (7.5 to 10 cm) in diameter. Store all harvested fruit in the refrigerator for up to several weeks. Flowers are also edible, and are good stuffed, baked or fried. Harvest flowers in the early morning.
Special Tips: In small garden areas, grow vining squash on a fence or a trellis.
The summer squash information above applies to the following squash:
Pattypan Squash (Cucurbita pepo) – Also called scallop squash.
Yellow Squash (Cucurbita pepo) – Can be either straightneck or crookneck.
Zucchini (Cucurbita pepo) – There are yellow zucchini, green, and round zucchini.