Horticulture/Summer Squash

The Summer Squashes are a group of plants in the species Cucurbita pepo, which are grown for their fruits. They come in many varieties among several major groups including: Yellow Summer, Zucchini, Crookneck, and Cousa. While there are some differences in flavor between these groups, their cultivation is essentially the same.

Summer squashes grow on short vines, appearing bushy in the field. The leaves are large, palmately lobed, and usually variegated with white or pale green.

These plants are highly productive, particularly when the fruits are harvested while young: gardeners growing these plants often have plenty of produce to share with friends. The flowers are also edible and both male and female flowers are harvested for this purpose.

Growing Conditions
Summer Squashes grow in full sun or light shade. They require a rich soil for good fruit production.

Direct Seed
Summer Squashes grow easily from seeds sown in situ. Plants should be thinned to 18 to 36 inch (45-90 cm) centers. Seeds can be sown as soon as the soil warms up.

Seedlings in Containers
For growing transplants, sow 2 seeds per 3 or 4 inch pot. Seedlings grow quickly in warm weather, so should not be started before the planting area is prepared.

Transplanting
Transplants should not be broken up or have their roots cut unless severely rootbound. Soil may be mounded up to the lowest set of leaves.

Early Spring
Enrich planting area with composts, but not with manures, as too much nitrogen may reduce the fruiting.

Summer
Pick regularly to avoid over-ripening and encourage further fruit set. If small fruits appear wrinkled or discolored, remove them (they may not have been pollenated). Monitor for Squash vine borer. Hill up composts to the lowest leaf set, adding more as the lower leaves yellow off (the small early leaves will die off naturally as the upper leaves shade them out). This provides both nutrients and some protection for SVB. Keep the growing area free of weeds, but maintain nectar sources nearby to ensure an ample supply of pollenating insects.

Fall Cleanup
Burn borer-infected vines, and till area to disturb any coccoons. If rotation is not possible, use a winter cover crop such as rye, vetch, or pea to enrich the soil.

Harvesting
Cut the stems with a sharp knife. Summer squashes are best harvested well before the fruit matures, as the seeds become hardened in large fruit. Fruits can be harvested even before the flowers fully open if desired.

Propagation
By seed, from the mature fruits. If collecting seed, allow the most productive plants to produce a single mature fruit towards the end of the season, picking it after the plant is frost-killed.

Fungal Diseases
Powdery Mildew

Arthropod Pests

 * ../Squash Vine Borer/
 * ../Cucumber Beetles/
 * ../Squash Bug/

Yellow Summer Squashes

 * Multipik
 * Sunray

Cousa Squashes

 * Magda

Zucchinis

 * Cashflow