Squash, Winter and Summer

Sowing date: Having warm-enough soil is everything.  At Elkton I first attempt squash about April 15.  In the Willamette, May 1 is usual.  Farther north, squash may not come up until June 1.  Dry gardeners should not transplant squash; the taproot must not be broken.

Spacing: The amount of room to give each plant depends on the potential of a specific variety’s maximum root development.  Most vining winter squash can completely occupy a 10-foot-diameter circle.  Sprawly heirloom summer squash varieties can desiccate an 8-or 9-foot-diameter circle.  Thin each hill to one plant, not two or more as is recommended in the average garden book.  There must be no competition for water.

Irrigation: With winter storage types, an unirrigated vine may yield 15 pounds of squash after occupying a 10-foot-diameter circle for an entire growing season.  However, starting about July 1, if you support that vine by supplying liquid fertilizer every two to three weeks you may harvest 60 pounds of squash from the same area.  The first fertigation may only need 2 gallons.  Then mid-July give 4; about August 1, 8; August 15, feed 15 gallons.  After that date, solar intensity and temperatures decline, growth rate slows, and water use also decreases.  On September 1 I’d add about 8 gallons and about 5 more on September 15 if it hadn’t yet rained significantly.  Total water:  42 gallons.  Total increase in yield:  45 pounds.  I’d say that’s a good return on water invested.

Varieties: For winter squash, all the vining winter varieties in the C. maxima or C. pepo family seem acceptably adapted to dry gardening.  These include Buttercup, Hubbard, Delicious, Sweet Meat, Delicata, Spaghetti, and Acorn.  I wouldn’t trust any of the newer compact bush winter varieties so popular on raised beds.  Despite their reputation for drought tolerance C. mixta varieties (or cushaw squash) were believed to be strictly hot desert or humid-tropical varieties, unable to mature in our cool climate.  However, Pepita (PEA) is a mixta that is early enough and seems entirely unbothered by a complete lack of irrigation.  The enormous vine sets numerous good keepers with mild-tasting, light yellow flesh.

Obviously, the compact bush summer squash varieties so popular these days are not good candidates for withstanding long periods without irrigation.  The old heirlooms like Black Zucchini (ABL) (not Black Beauty!) and warty Yellow Crookneck grow enormous, high-yielding plants whose extent nearly rivals that of the largest winter squash.  They also grow a dense leaf cover, making the fruit a little harder to find.  These are the only American heirlooms still readily available.  Black Zucchini has become very raggedy; anyone growing it should be prepared to plant several vines and accept that at least one-third of them will throw rather off-type fruit.  It needs the work of a skilled plant breeder.  Yellow Crookneck