Spaghetti squash (Cucurbita pepo) -- Mother Nature's answer to homemade pasta, minus the work and calories -- doesn't ripen off the vine. Any spaghetti squash that hasn't ripened completely before the first frost isn't edible, and harvesting and curing won't help. To get the biggest yield from your spaghetti squash vines, plant them with enough time to mature before your earliest fall frost date. This may mean giving the seeds an indoor head start.
Days to Harvest
Days to harvest means the time required for spaghetti squash to ripen from when the seeds germinate or start growing, not from when the seeds are planted. Most spaghetti squash varieties ripen in 90 to 110 days. So for a safe estimate of when to plant your seeds, add a five- to 14-day germination period to the days-to-harvest number shown on your seed packet and subtract or count back the total from the average first fall frost date in your U.S. Department of Agriculture plant hardiness zone.
When Time Is Short
If your growing season -- the interim between the date of the average last spring frost date and the first fall frost date -- is less than 90 days, start your spaghetti squash seeds indoors at least one month before your average last spring frost date.
Fill each peat pot with seed starter mix and level its surface.
Press three or four squash seeds into each pot to the depth recommended on the seed packet.
Fill a pan with enough water to cover the bottom two-thirds of the peat pots. Set the pots in it to absorb water overnight.
Cover the top of the pan with clear glass or plastic wrap.
Set the pan out of direct sun, where the temperature ranges from 65 to 75 degrees Fahrenheit.
Check the plants daily and add water to the pan whenever the surface of the seed-stater mix feels dry.
Remove the glass or plastic wrap when the seedlings have germinated or sprouted, and move the pan to a bright area, such as a spot near a south-facing window.
Fertilize the seedlings every two weeks with liquid houseplant food at one-half the label's recommended rate by pouring off the water in the pan and replacing it with the fertilizer and water solution.
Pinch off the two smallest seedlings in each pot after all of them have their first set of true leaves. These are the leaves they'll keep, and they look different from the temporary leaves, or cotyledons, that pop open when the seeds sprout.
Move the remaining seedlings to a sheltered outdoor location when they have three sets of true leaves. Let the seedlings harden off for at least three days, but don't plant them until the soil temperature is at least 65 F. To minimize transplant shock, set the plants out in their peat pots, covering the pots completely, and water them well.
Maximizing Your Harvest
Your seedlings will produce the most fruit if you plant them in organically rich, well-drained soil where they'll get six hours of daily sun. When weekly rainfall measures less than 1 inch, water to make up the difference. Side-dress each vine with a handful of organic compost just before the vine starts to spread and again as soon as it begins blooming.
Harvesting and Storing
Harvest spaghetti squash when its rind is too tough to puncture with your thumbnail. To keep disease from spreading, snip the squashes from the vines with clean, sharp pruning shears disinfected with rubbing alcohol between cuts. Leave a 2- to 3-inch stem on each squash.
Handle the squashes gently so they don't bruise, and clean them with a soft, damp cloth. Cure them -- hold them in open air at 70 to 80 F for two weeks -- so they slowly release moisture. This concentrates their flavor and extends their storage life. If it's warm enough to cure them in the garden, keep them off the ground to protect them from soil fungi, space them for good air circulation and turn them frequently so they release moisture evenly. Then store them for up to five weeks in a cool, dry spot -- such as an unheated basement or garage -- at 50 to 55 F.
Things You Will Need
- EXtension.org: How Do I Determine When My Spaghetti Squash Are Ready to Be Picked, and Will They Continue to Ripen Once Picked?
- Harvest to Table: How to Grow Winter Squash
- University of Illinois Extension: Starting Vegetable Seeds Indoors
- Iowa State: Growing Squash in the Home Garden
- Reimer Seeds: Schultz Liquid All-Purpose Plant Food Plus
- University of Minnesota Extension: Growing Pumpkins and Winter Squash in Minnesota Home Gardens
- Organic Gardening: All About Growing Winter Squash
- Bonnie Plants: How to Store Winter Squash
- University of Illinois Extension: Garden Terms Demystified
- New York Horticultural Study Guide for Youth: Glossary of Horticultural Terms