Squash & Pumpkin
Ancient members of the Cucurbit family, both winter and summer varieties provide the home garden with an array of shapes, colors, textures, and taste!
Plant care & info
All squash need at least 6 hours of direct sun and rich, well‐drained soil. Vining winter squash and pumpkins will need 4‐5’ of space 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 an all purpose granular fertilizer in the bottom of each planting hole.
Squash thrive in warm weather and are best planted outdoors from 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. Start seeds indoors in May, 3 weeks before the desired transplanting date. Squash does not like root disturbance, so we recommended starting seeds indoors and in pots which can then be planted directly in the ground.
When planting outside, 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, leaving only 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 a floating row cover to prevent cucumber beetles and other insects. Remove row covers when plants begin to flower. Organic mulches can help heat the soil and retain moisture.
How much water your plants will require depends on the soil and weather. Squash want average, evenly moist watering during their 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. It also prevents water from landing on the leaves, the presence of which can lead to several disease issues.
Squashes are minimal feeders. A good organic fertilizer mixed into the soil before planting will keep squashes happy. If desired, supplement throughout the growing season with a liquid fish and/or kelp emulsion, or side dress with composted manure midseason.
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. If the weather is dry, allow winter squash to cure in the garden for 15 days. Otherwise, cure them in a warm, dry space for 15 days for optimum storage abilities.
Washing the skin with a diluted bleach and water solution will remove possible fungal spores which may cause early molding.
Summer squash can be stored for a week when refrigerated. Winter squash can store for 3‐4 months at 55°F.
- Flowers may not form fruit for a variety of reasons. Most Squash have separate male and female flowers. Often, the first flush of flowers are all male. Other times, you may have female flowers with tiny fruits that never develop and fall off. In this case, a 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 set the fruit.
- 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 the 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 or 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 methods to control aphids, such as ladybugs and insecticidal soap.
Summer squash can be harvested throughout the season. They have soft skins and are eaten fresh. Winter squash are harvested once. They have hard outer skins and are cured for winter storage and eating. Pumpkins are grown like winter squash.
