How Late Can You Plant Spaghetti Squash?

First Frost Date

• The latest date you can plant spaghetti squash in your area is determined by the first fall frost date. The squash plant is a tender annual and cannot tolerate any frost; the vines will die when freezing temperatures arrive. Spaghetti squash require 80 to 100 days of warm, sunny days to grow from seed to harvest. By counting back 15 weeks, or 105 days, from the first fall frost date, you can ensure that your squash have enough time to grow and produce fruit before the first fall frost arrives. For example, if the first frost date is October 1, use a calendar to count back 15 weeks, making your planting date no later than the week of June 18.

Planting the Seeds

• Spaghetti squash usually grow on 8- to 10-foot vines. If your space is limited, consider planting a bush variety such as "Hasta La Pasta," "Orangetti" or "Tivoli." Plant the seeds when the soil has warmed to 65 degrees Fahrenheit, two weeks after the last frost date in your area. Preparing a garden bed with 2 inches of compost dug 12 inches into the soil provides a rich, loose soil for the plants. The amended soil is raked into rows spaced 7 feet apart, in a series of wide, flat-topped mounds spaced 5 feet apart. Three to five seeds are planted 1 inch deep in each mound and thinned to one plant per mound after sprouting.

Water and Fertilizer

• Squash seeds require warm, moist soil to germinate. Covering the mounds with plastic sheeting and planting the seeds through a hole helps keep the soil warm and reduces water loss by evaporation. Water thoroughly after planting and continue to water when the soil is dry to the touch. One tablespoon per plant of 10-10-10 fertilizer is applied one week after the plants begin blooming. Fertilize the plants again at the same rate three weeks later. Always water before fertilizing to prevent the fertilizer salts from burning the plants' roots, and water thoroughly after applying fertilizer. Organic gardeners can water the squash plants every two weeks with compost tea.

Pest Problems

• Aphids, whiteflies, cucumber beetles and squash bugs are among the pests that attack the plants and developing fruits. Aphids and whiteflies may be removed by a strong stream of water. Cucumber beetles are controlled with insecticides such as carbaryl dust, which is applied at a rate of 1/2-teaspoon per plant. Adult cucumber beetles overwinter in vegetation and garden debris; cleaning the garden bed after harvesting the fruits may reduce the beetle population in the following year.

The Harvest

• Spaghetti squash are allowed to ripen on the vine until the fruits turn a solid off-white, yellow or orange, depending on the variety, and the outer shell is hard. Depending on your first frost date, the fruits are harvested in September or October by cutting the stem 2 to 3 inches from the fruit with anvil pruners or a sharp knife. Store the fruits in a garage or shed at a temperature of 45 to 55 degrees Fahrenheit for two to six months.