Saving Squash Seeds

There are six species of squash (all are Cucurbita genus):
—Cucurbita maxima—ie. Bananas, Buttercups, Hubbards, Marrows—very long vines, huge hairy leaves
—Cucurbita mixta—ie. Cushaws—spreading vines, large hairy leaves
—Cucurbita moschata—ie. Butternuts—spreading vines, large hairy leaves
—Cucurbita pepo—ie. Acorns, Cocozelles, Crooknecks, Scallops, Vegetable Marrows, Zucchinis—prickly leaves and stems
—Cucurbita ficifolia—plants are perennial in warm winter climates; fruits greenish cream mottled skin; used in Mexico to make candy
—Cucurbita foetidissima—perennial in frost-free areas; leaves have disagreeable odor when brushed; fruits not eaten, but seeds pressed for oil

Squash plants will not cross-pollinate between these six species, but there are many varieties withing each specie that will cross-pollinate. For example, the butternuts won't cross-pollinate with the banana squash; but the crookneck and scallops could.

If you want to save squash seeds that will be true to the variety, to plant the next year or to trade seeds with someone else, you need to be careful. "Different varieties within the same species must be separated by 1/2 mile or must be hand-pollinated, so be sure to check neighbors' gardens for varieties that could ruin your isolated plantings."(from Seed to Seed, by Suzanne Ashworth).

Ashworth suggests how to hand-pollinate to guarantee seed purity. She says to check in the evening for male and female flowers that will open the next morning. These flowers are yellowish and may start to open at the tip. "Use 3/4" masking tape to securely tape the tips of the blossoms shut. Morning dew will sometimes cause cheap brands of tape to burst open, so be sure to select a brand that is sticky."

To help with genetic diversity, switch male and female flowers from more than one squash plant of the same variety (ie.–two or three plants of the same kind of zucchinis). Once the dew is dry (the female flower will need to be re-taped), pick the male flowers as I showed yesterday. Remove the tape and petals from the male flower. Gently pull off the flower tip and tape from the female flowers—the flowers will open slowly. Swab the male anthers onto each section of the female stigma (as shown in yesterday's post). Even better results occur if two male flowers are used for each female flower. Several female flowers may be opened at the same time and the same male flowers used for them all, just be careful that bees don't sneak in to help!

Next, re-tape the female flowers to completely close the flower. It can be completely taped if necessary, just be careful not to damage the neck between the flower and the squash itself, or it might be aborted. Bumblebees and some solitary bees may chew through the flower petal to get to the pollen. If this is a problem, use 2" tape and cover the entire flower. Or, the entire plant could be covered until the flower petals wilt down over the female flower, making it harder for the bees to chew through.

Grow the squash until it is quite large and fully mature. Remove seeds three weeks after harvest. Squash can be smashed or cut open. Gather all of the seeds and rinse in a colander under a stream of water; remove all strings and debris. If squash flesh is still attached to the seeds, rub the seeds in a wire strainer under running water to loosen it. Drain the seeds and dry. Store in a cool, dry, dark place and the seeds can remain in viable condition for six years.