Winter Squash Seeds - Kabocha

Squash and gourds are all warm season crops that do best when direct seeded in the garden after all risk of frost has passed. Some gardeners in areas with short growing seasons choose to start these crops early and transplant them out, but this method requires extra care, as the seedlings are delicate and susceptible to transplant shock. All types of squash and gourd need to be started at the same time, but take different lengths of time to mature. Summer squash is usually ready to harvest about 60 days after seeding, whereas winter squash and gourds need anywhere from 90 to 120 days depending on the variety.

Choose a location in full sun with well drained soil high in organic matter, and make sure the soil temperature has reached 60 degrees F before seeding squash or gourds. Pay attention to the growth habit of the variety you’re planting to determine the proper spacing. Bush types (including most summer squash varieties) should be planted 12 inches apart in rows 2 to 4 feet apart, while vining types (including most winter squash) should be given more space to spread out, around 12 square feet apiece, whether by leaving extra space between rows or between plants. Vining squash plants generally prefer to ramble along the ground and will not grow vertically, while many gourds (mainly Lagenaria species) will climb a trellis if one is available. Growing gourds on a trellis or fence is a great way to save space and also produces gourds that are more pleasingly shaped. Regardless of spacing, plant your seeds about 1 inch deep, and two seeds to a hole, then thin the seedlings to keep the strongest ones after they have germinated. Make sure to water the seeds thoroughly at planting. Once the plants are established, they will need about 1 inch of water per week, like most vegetable crops.

Summer squash is ready to harvest as soon as the fruits reach a usable size, typically 6 to 8 inches long for most varieties. Check on your summer squash plants daily, and harvest regularly to keep them producing for as long as possible. Never leave an overgrown squash on the plant, since this will trigger the plant to stop setting new fruit. Winter squash is usually harvested shortly before the first frost, once the fruits have reached their mature color and the rinds have begun to harden. Often the vines will also begin to die back as the fruit reaches maturity. Most winter squash reach their best eating quality after being stored indoors for a period (called curing) - how long depends on the variety. Gourds should be harvested when the stems turn brown and begin to dry out. Bottle-type gourds that are ready for crafting will feel light, have fully hardened rinds, and the seeds should rattle inside.

Squash (Cucurbita pepo, Cucurbita moschata, Cucurbita maxima, Cucurbita argyrosperma) and gourds (Cucurbita pepo, Luffa aegyptica, Lagenaria siceraria) are insect-pollinated annuals that produce separate male and female flowers on the same plant. In order to save pure seed, up to a half-mile of distance or some type of physical barrier between different varieties of the same species is required. Most seed savers either choose to grow only one variety of any given squash or gourd species, or they bag and hand-pollinate individual flowers to prevent cross-pollination. In order to hand-pollinate squash or gourd flowers, you must place a mesh or light fabric bag over the female flowers you want to pollinate before they open, so that no insects get to them before you do. Once a bagged blossom is open, transfer pollen from a male flower to the female flower using a cotton swab or paint brush, then replace the bag over the flower until the flower closes again and the fruit begins to form. Make sure to tag any hand-pollinated fruits that you intend to save for seed with ribbon or tape so you don’t lose track of them! All squash and gourds must be grown to full botanical maturity in order to save viable seeds. For winter squash and gourds, this simply means harvesting the fruits the same way you normally would for food or crafting uses. For summer squash, this will mean leaving them on the plant much longer than you normally would for food use. Botanically mature summer squash will be much larger than when harvested for eating, and the rind will typically toughen and change color to yellow or orange, or become duller in appearance when the fruits are ripe. To harvest the seeds, simply scoop them out of the fruit and rinse off any flesh in a colander, then dry them spread out on screens or newspaper. Gourd seeds are typically harvested after the fruit is completely dry, and may not need any cleaning at all. Once the seeds are fully dry, store them in an airtight container in a cool, dark and dry location.