Squash Seed Saving
Now is the time to be eating all those winter squash harvested in the fall. For squash seed savers, this is the opportunity for quality control and seed selection. Easy control over the selection process is one reason squash seed saving is so much fun. Squash eaters know that there can be large differences in quality from one squash variety to another, and even within one variety there are good ones and not-so-good ones. I happen to like a sweet squash with smooth texture and a modest moisture level; my dad likes the dry ones that are happy to accept a big pat of butter. It’s all a matter of taste — and if I’m saving the seeds, I get to decide which ones to plant!
Any vegetable variety is at its best when there is constant selection for the best eating quality. For some plants, this can be a challenge. For instance, with root crops you have to dig them, sample part of the root for flavor, make your selection, and then replant those that have merit for seed production. Squash, however, yield their seed when it’s time to eat them. All of the fruit that I have hand pollinated are tagged, so when the time comes, I know the parentage. I cut the squash open, being careful not to cut too many seeds, scoop them out, wash them a bit, and set them to dry in an old pie tin. Then I cook the squash and try to objectively rate various properties, such as flavor, sweetness, texture, moisture, and size. As I have accumulated more saved seed with potential merit, it has been necessary to write all this down, so I have the records to potentially mix and match parentage down the road.
Squash are insect-pollinated out-breeders. Under normal circumstances, the bees will visit many flowers on one trip, and in the process generate crosses to all the same-species that are flowering in the garden. There are two ways to gain control over the potential genetic chaos in your typical home garden. You can grow only one variety of squash per squash-species and maintain adequate isolation from your neighbor’s plants, or you can practice hand pollination. I do both, hand pollinating cucurbita maxima and c. pepo, and only planting one variety of c. moschata (butternut). The worst offenders for generating inedible crosses are the pepos. The diversity in this species is truly amazing, from zucchini, gourds, and pumpkins, to acorn squash, spaghetti squash, pattypans, delicatas, and others. Crosses with these varieties usually bring out the worst qualities of the parents so pepos that arise out of the compost are usually best pulled as weeds. The maximas are also a diverse lot, but the ones I grow are all destined to be winter keepers, so many of the qualities I’m looking for are common to several varieties. The varieties I’ve grown in the last few years have included my own Buttercup/Kabocha selections as well as Triamble, Marina di Chioggia, Oregon Sweet Meat, and Amber Cup. Crosses between these varieties have a better potential to be edible, so I often leave a few of the maxima volunteers in the garden — on the lookout for surprises.
Most out-breeders count on wide genetic diversity to maintain vigor, but squash are unusual because they do not suffer very much from inbreeding depression. This is another reason why squash are such fun plants from which to save seed. There is endless diversity in the squash world; crosses can give you new characteristics quickly, and you can select for new desired characteristics by inbreeding a few individuals without major loss of vigor. However, excessive inbreeding should probably be avoided unless you are trying to isolate a particular trait.
If you have gotten this far, you had better pick up Carol Deppe’s book, Breed Your Own Vegetable Varieties. This is a delightful read and a great reference for any seed-saving gardener.