Winter squash is an annual fruit representing several squash species within the genus Cucurbita. It differs from summer squash in that it is harvested and eaten in the mature fruit stage when the seeds within have matured fully and the skin has hardened into a tough rind. At this stage, most varieties of this fruit can be stored for use during the winter. Winter squash is generally cooked before being eaten, and the skin or rind is not usually eaten as it is with summer squash, though several winter squashes can be harvested young as a “summer squash”.

A pumpkin, on the other hand, is typically a cultivar of winter squash that is round with smooth, slightly ribbed skin, and most often deep yellow to orange in coloration. The thick shell contains the seeds and pulp. The name is most commonly used for cultivars of Cucurbita pepo, but some cultivars of Cucurbita maxima, C. argyrosperma, and C. moschata with similar appearance are also sometimes called "pumpkin". And generally any of those winter squashes that even resemble the shape of a traditional pumpkin pass as such during the season.

Pumpkins and winter squashes are a celebration of fall. Because they often store well, they were once very important to people when the grocery store wasn’t offering almost any kind of food at any time of year. To many people, they still are of such importance, not just around the world where grocery stores are not prevalent, but for people trying to pull away from their dependence on such.

Tromboncino Squash is a winter squash that is picked young as a summer squash (with nice firm texture).

Squashes are annual vines and are either left to sprawl around the ground, or grown up on trellises, fences, or arbors. Fruits that are grown, hanging from vines, can take on a more stretched-out shape that many find appealing and fun (though not always).

Tahitian Squash needs as long of a season as you can give it.

People commonly mistake the name “winter squash” as to suggest this is a squash that one grows in the winter, but in fact, all squashes are warm-season annuals that are killed by frost/cold weather. Occasionally in SE Arizona plants can last well into or even through the winter when the temperatures haven’t dipped much below freezing.

Marina di Chioggia, squash or pumpkin? You decide.

Some winter squashes need as long as you can give them, particularly the tropical heirlooms like Tahitian squash, and you should start them indoors or in a greenhouse in January or even December, and plant out when threat of frost is over, or plant sooner and protect plants in the ground from frost. Seeds of most winter squashes can be started direct seeded into the ground.

Full to part sun is best with amended garden soil, and even, regular water. Mulch roots with straw or a coarse compost/mulch, and feed regularly with an organic fertilizer. Some winter squashes will start producing as soon as plants are big enough to start blooming and fruiting, while some may wait until monsoon or even fall to start fruiting.

Mellittia cucurbitae, the Squash Vine Borer. Gorgeous, but a menace to squash growers.

The squash vine borer (Melittia cucurbitae) is a wasp-mimicking moth that sometimes causes squash plants to collapse. The eggs of the squash vine borer are laid singly on the lower part of the main stem of the host plant, as well as on the leaf stalks, leaves, and fruit buds. Some eggs are laid in the cracks in the soil near the base of the plant. The adult does this during the day because it is a diurnal (daytime flying) adult. Females usually lay eggs about one day after emergence from pupae in the ground. The eggs hatch in 8 to 14 days. Newly emerged larvae burrow into vines, where they feed on the host plant tissue. The larvae develop through four instars in four to six weeks. The late instar larvae drop to the ground and burrow 25-50 mm into the soil to pupate. The pupae complete development in 14 to 30 days. In the field, the average lifespan of the females is about five days and that of males is about three days.

Squash vine borer larvae. If you catch them at this stage, you can remove.

If you watch the squash vines closely, look for any wilting that isn’t related to heat/lack of water. If you hunt for the larvae, you can cut them out. You will lose the top of the squash vine, most likely, but the bottom will branch out and persist. You can also just plant enough squash plants (if you have the space) that if you lose a few to this moth, it isn’t a big deal. Any attempts at poisoning are usually futile.

Fall is for Winter Squash, or Pumpkins

Spadefoot Nursery

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