Grow Your Best Series-Summer Squash and Zucchini

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summer squash

Summer Squash and Zucchini: A bountiful addition to any home garden

Summer squash and zucchini are loved by home gardeners who appreciate their productivity and being relatively easy to grow. Non-gardening neighbors may have a different opinion. Come July, they can count on loads of baseball-bat sized squash showing up on their porch, forcing them to heat up the oven and invest a day in baking enough zucchini bread to get the whole neighborhood through winter. In spite of this mixed reputation, they are a great crop for new gardeners to try.

Squash grow best in well-drained sunny sites, preferring lots of organic matter in the soil. Incorporate compost, and any lime or fertilizer needed ahead of planting. Squash require ample water so plant them close to a water source or provide irrigation. Squash can be started 3-4 weeks and transplanted after the risk of frost has passed. They also grow very well from seed. Set or plant seeds 3’-4’ apart in a row or on hills. Sow 2-3 seeds per hill and thin to one – two plants. Landscape fabric, straw mulch, or even cardboard mulch will help keep weeds down but also keep fruit clean, and reduce soil splashing onto leaves. Squash have separate male and female flowers and require visits from bees and insects for pollination.

Summer squash and zucchini are immature fruit of a squash plant. There are many different varieties of both of these, and collectively can be called “summer squash”. Harvested when young, the skin is tender, and they can be eaten raw or cooked. Yellow crookneck and straightneck squash, saucer-shaped Patty Pan squash, and the hybrid multi-colored squashes such as ‘Zephyr’ and ‘Sunburst’ are summer squash varieties to try. There are different types of zucchini, too. Consider trying a globe-shaped Eight-ball zucchini, or the elegant Italian heirloom Costata Romanesco for something different.

Like any good garden plant, summer squash have their insect and disease menaces. Cucumber beetles are small yellow and black beetles that feed on leaves, damage fruit, and transmit disease. Control them early with an insecticide such as spinosad or pyrethrin. Keep in mind that insecticide applications during bloom can harm pollinators. Reduce sprays and spray only in late evening to reduce exposure for bees and pollinators. Squash bug are a newer but very damaging pest. A true bug, they are grey and resemble stink bugs. When they feed on foliage, they cause leaves to turn brown and yellow from the edges. As they are not well-controlled with insecticides, scout for their shiny, brown eggs and destroy them immediately to keep populations low.

Squash vine borer comes from a moth that lays eggs at the base of a plant. The borer, a cream-colored grub-like larva, burrows into the stem to feed. If present, you will notice an incision and sawdust-like frass at the base of the plant. You can actually cut into the stem and remove the larva, then burying the incision with soil. Cover vines with soil at a few of the nodes to encourage auxiliary rooting. Scout for the large red and black moths in early morning and late evening and place in a bucket of soapy water to prevent further egg-laying. Pickleworm is a late-season pest that will damage fruit, especially the Patty Pan varieties. Its moth lays eggs close to the stem. The eggs hatch and the larvae, a small worm, will bore into the fruit, leaving perfectly round holes. To protect against these insects, cover your squash with row covers or lightweight insect netting until bloom. Remove covers at bloom to allow pollination.

Major diseases include powdery mildew, and anthracnose. To limit spread of these, remove infected leaves when you see them. There are powdery-mildew resistant varieties available, and sulfur fungicides can also help control it. Mulching helps control other foliar diseases. Squash bug, cucumber beetle, and the diseases can be reduced by rotating crops in the garden- moving them away from where they were planted the year before, and burying crop residues at the end of the season.

Harvest squash when they are fully formed but still small, for best quality. To catch them before they get too big, check squash every day for fruit that may be ready to harvest. If left too long, the skin and seeds begin to harden, making the fruit less palatable, especially for raw eating. Squash blossoms are also edible. Harvest male flowers only, first thing in the morning, leaving at least 50% of scattered through the patch for pollination. Refrigerate immediately until use. They are excellent in eggs, on pizza, or stuffed and fried.

This year, I challenge the experienced gardener to stagger their squash crop. Check the days to maturity on each of your squash varieties. If most of them will mature at a similar time, consider adopting a “succession planting” strategy to stagger the harvest. Plant one-third of your total plants every 10 days – 2 weeks over the course of a month. In addition to preventing a food-processing headache, staggered planting can ensure a crop if one is lost to pest or weather issues.

With further questions about gardening, contact Eli Snyder at the N.C. Cooperative Extension, Wilkes County Center at 336-651-7333 or elina_snyder@ncsu.edu.