Black zucchini is a variety of summer squash that is commonly found in markets and grocery stores. The fruit gets its name from its dark green, almost black skin. Black zucchini plants produce fruit with white flesh and a delicate flavor.
Summer squash plants are in the family Cucurbitaceae, also known as the gourd family. Black zucchini is an heirloom zucchini variety that was introduced into the United States in the 1920s. Its species name is Cucurbita pepo. This variety of zucchini is closely related to summer squash and some pumpkin varieties.
Black zucchini is an open pollinated rather than a hybrid variety. Hybrid zucchinis are cultivated through careful cross breading. Often, when the seeds are collected from hybrid varieties and planted, the new plants do not resemble the parent plants.
Open pollinated varieties, like black zucchini, can be planted from collected seeds. The plants also can be cross-pollinated with other members of the Cucurbits pepo species. If cross-pollination is not desired, it is best to plant only one variety of summer squash or space the plants apart in different areas of the garden. Though cross-pollination won't affect that season's crop, the seeds from cross-pollinated plants often combine characteristics of two different varieties.
Black zucchini is an annual vining plant that grows in warm, frost-free weather. The seeds should be planted in a prepared garden bed in the spring at least two weeks after the last frost date. The seeds require a warm growing environment and do not germinate in soil below 70°F (about 21°C). The seeds germinate and emerge in three to 12 days; they'll germinate rapidly at 90°F (about 32°C) and take longer in cooler soil closer to 70°F (about 21°C).
The seeds should be planted 1 inch (about 2.4 cm) deep and 2 to 3 inches (about 5 to 8 cm) apart. Once the seedlings emerge from the soil and develop the first set of true leaves, they can be thinned to a spacing of 8 to 12 inches (about 20 to 30 cm). The true leaves are the second set of leaves that emerge after the first "seed" leafs.
Black zucchini is commonly harvested at 8 inches (about 20 cm) long. When left on the vine longer, the zucchini can develop a woody texture. The developing fruit is edible at any stage and can be picked sooner for a more delicate flavor.
Though zucchini is a fruit, in cooking it is treated more like a vegetable, both in terms of preparation and seasoning. Black zucchini commonly is used in stir fry recipes, soups, and other vegetable dishes. It also can be eaten raw in salads or with dip, and this zucchini variety is well suited for freezing.