Seed saving

When are seeds mature?

Individual squash fruits are ready for seed harvesting by 60 days after the fruit is fertilized. If the peduncle between the fruit and the vine is still fleshy and hydrated, the vine is still providing nourishment to the fruit and seeds and it may help to leave the fruit attached.

If frost or other issues do force early harvesting, seeds can continue to develop after harvest if left inside the fruit. A publication from Maine Organic Farmers and Gardeners offers minimum recommended timelines for squash fruit and seed maturation: Harvesting Winter Squash for Flavor and Storage. If your fruit may not have mature seeds yet, consider waiting to process the seeds for a month or two after harvest.

Recommendation: Taste fruits first

Taste at least one fruit from any plant that you are saving seeds from. Squash flavor can be evaluated either raw, or cooked without butter or seasoning.

Processing seeds

Going to Seed has published a standalone guide to saving squash seeds which offers two overall options depending on your preferences and circumstances. Both the ‘dry’ and ‘wet’ processes can be used with cushaw seeds.

Humid climates: dry enough to snap

Climate is an important consideration for drying seeds. In humid climates, a dehydrator set to 100 degrees or less can help seeds dry enough for storage. Some seed savers employ reusable desiccants to mitigate humidity.

Working Food, in Florida, USA, reports in their seed drying fact sheet that humidity is their biggest obstacle to seed longevity. In that area, where ambient humidity ranges from 50%-100% depending on the season, seeds never reach Working Food’s recommended dryness of 35% or lower via air drying.

It’s essential that the seeds be very dry before storage. Seeds are dry enough when they snap crisply if bent in half.Many seed savers use locations near a fan, or on top of the refrigerator, or near a heating or cooling vent, where circulating air helps the drying process.

Using a dehydrator

While some guides for seed saving discourage the use of a dehydrator out of concern for accidentally harming the seeds, seed savers in humid climates have found dehydrators safe for squash seeds when used at low temperatures. The report from the ECHO Community seed bank about their humid climate dehydration trials in Thailand indicates that 100 degrees Fahrenheit or lower is safe for seeds from most crops.

If you are using a dehydrator to dry seeds for the first time, consider running the dehydrator for one hour at a time so you can check the drying progress. In a humid climate, air-dried seeds may only need two or three hours in the dehydrator before going into long-term storage.

Storing squash seeds

Dry seeds are not completely dormant; they still respire at a very low level, consuming resources stored in their tissue. In addition to risking mold or decay, storage at higher temperature or humidity increases respiration, depleting the seed’s reserves and decreasing vigor and viability over time.

Ideally, store dry seeds in a cool, dry space in airtight glass or thick plastic containers, or plastic bags designed for freezer use that are 4 mil or greater in thickness. If rodents, insects and other seed eaters are a problem, glass jars, metal boxes or 5-gallon plastic buckets with tight-fitting lids offer protection.

One tool for humid climates is moisture absorbing desiccant packs, which can be added to long-term storage containers along with the seeds. These packs can be dried out and reused many times. Another article from ECHO Community describes a low-tech approach for vacuum sealing, which can be useful in damp regions.

The Garden Professors published a useful article discussing long-term seed storage in more detail: When Good Seeds Go Bad: How long can you store seeds? The grower’s climate and storage space will determine the methods that work best. New seed savers should check saved seeds regularly to catch problems early.