Growing summer squash in zone 8b

In zone 8b, the average last spring frost falls between late February and mid-March depending on specific location. Direct sowing or transplanting can begin as early as early March once soil temperatures reach 60°F consistently. Under these conditions, first harvest typically arrives in late April to May, roughly 50 to 60 days after planting.

Peak summer heat (daytime highs above 95°F from late June through August) can suppress fruit set as plants reduce pollination activity under heat stress. A second planting made in mid- to late August takes advantage of cooling fall temperatures and typically runs productively through October or into November before the first frost, which arrives on average in late November to early December in zone 8b.

The main adjustment in zone 8b is managing the mid-summer production gap. When daytime temperatures exceed 95°F consistently, fruit set drops and plants become more susceptible to powdery mildew as stressed tissue loses resistance. Keeping soil consistently moist without waterlogging helps maintain plant vigor during heat peaks; mulching with 3 to 4 inches of straw or wood chips limits soil temperature fluctuation and reduces moisture loss between irrigations.

Powdery mildew and downy mildew both escalate in late summer as humidity rises after afternoon storms; weekly inspection starting in August allows early intervention before infections establish. On sandy, nematode-prone soils, rotating squash plots on a three-year cycle with non-host crops (corn, small grains, or brassicas) is the most practical long-term management strategy. Solarizing fallow beds during July or August, when soil temperatures peak, provides additional nematode suppression before fall planting.