Squash & Pumpkin

Ancient members of the Cucurbit family, both winter and summer varieties provide the home garden with an array of shapes, colors and textures. Summer squash have soft skins, are harvested through the season and are eaten fresh. Winter squash have hard outer skins, are harvested all at once and are cured for winter storage and eating. Pumpkins are grown like winter squash.

Site Requirements

All squash need at least 6 hours of direct sun and rich, well‐drained soil. Vining winter squash and pumpkins will need 4‐5’ per plant depending on the variety. Allow 3‐4’ for bush varieties and summer squash. Prepare the planting area by mixing 3‐4” of composted manure and lime into the top 6‐10” of the soil. Mix in an all‐ purpose granular fertilizer in the bottom of each planting hole.

Planting

Squash thrive in warm weather and are best planted outdoors mid May through the first week of July when soil temperatures are in the 60s or above. They can be planted from seed or starts. You can start seeds indoors in May, 3 weeks before desired transplanting date. It is recommended to start seeds indoors in pots which can be planted directly in the ground, because squash do not like root disturbance.

Outdoors, space groups of seeds or plant starts 3‐5’ apart in hills or raised beds. Rows should be 6‐10’ apart. Sow 2‐3 seeds 1” deep and cover seeds with a thin layer of soil. Keep seeds slightly damp. Once seeds have germinated, pinch off the weakest ones, so you are left with the strongest one or two. Water in starts with a diluted liquid seaweed or vitamin B1 to alleviate transplant shock.

Keep new beds well weeded and slightly moist. You can cover new plantings with floating row cover to prevent cucumber beetles and other insects. Remove row covers when plants begin to flower. Plastic or organic mulches can help heat the soil and retain moisture.

Water Requirements

How much water your plants will require depends on the soil and weather. Squash want average, evenly moist watering in the initial growing phase. Reduce watering frequency as fruits begin to set, but avoid dramatic moisture fluctuations to minimize blossom end rot. A 1‐2” mulch layer helps maintain even moisture levels. Drip irrigation is the best way to provide even moisture and avoid water on leaves which can lead to disease issues.

Fertilizing

Squashes are minimal feeders. A good organic fertilizer mixed into the soil before planting will keep squashes happy. If desired, supplement throughout growing season with a liquid fish and/or kelp emulsion, or side dress with composted manure midseason.

Harvesting & Storage

Start harvesting summer squash when they are still young for optimum tenderness. Pick off all large summer squash to encourage continuous production. Harvest winter squash, leaving an inch of dried stem, before the first fall frost. Let winter squash cure in the garden for 15 days if the weather is dry, or cure in a warm dry space for 15 days for optimum storage abilities.

Washing the skin with a dilute bleach and water solution will remove possible fungal spores which may cause early molding.

Summer squash can store for a week if refrigerated. Winter squash can store for 3‐4 months at 55 degrees.

Pests and Diseases

• Flowers may not form fruit for a variety of reasons. Most Squash have separate male and female flowers. Often the first flush of flowers is all males. Other times, you may have female flowers with tiny fruits that never develop and fall off. In this case lack of pollination is the issue. Cool, cloudy weather can also deter pollinating insects from visiting your plants. Hand pollinate with a paint brush to help fruit set.
• Anthracnose appears as yellow and brown spots on leaves coupled with dark streaks on stems. It is a fungal disease that can be controlled with Serenade and copper sprays.
• Angular leaf spot appears as geometric yellow and/or brown leaf spots which eventually leave holes. It is a bacteria spread by splashing rain. Remove infected areas, avoid overhead irrigation, and use plastic mulches to prevent infection.
• Downy Mildew appears as splotches of angular yellow or brown spots that are purplish on the underside. Infected leaves should be removed. Spread of the infection may be controlled with Serenade, a fungicide.
• Powdery mildew will occur on all cucurbit crops at some point in the season. It may first appear as powdery white spots on leaves and stems, or coat entire leaves. The fungus spreads in warm, dry weather. Pick off infected areas and spray with copper or Serenade to prevent the spread of the fungus.
• Cucumber beetles may chew seedlings or leave a lacy pattern in leaves of larger plants. They transmit bacterial wilt. Use floating row covers over the crop until flowering begins. Beneficial nematodes can kill the larvae, lacewings and ladybugs will eat eggs, and rotenone and pyrethrin can help control populations.
• Melon aphids cause leaves to curl, distort and turn yellow. Usually white aphid skeletons and colonies of apple green bugs are visible on the growing tips and underside of leaves. There are numerous control methods to control aphids, such as ladybugs and insecticidal soap.