Growing arugula in zone 7b

In the piedmont, last spring frost typically falls between late March and early April. Arugula tolerates light freezes down to approximately 28°F, which allows direct sowing outdoors as early as late January or early February, well before last frost. The spring harvest window runs from mid-March through late May; plantings made after mid-April are likely to bolt before producing a full harvest cycle. Fall is the second window. Soil temperatures drop to arugula's preferred range (50 to 65°F) in late August, making that the practical start for fall sowing. Harvest continues through October and into November, and with lightweight row cover, plants often persist into December before hard freezes end the season. The 220-day growing season creates room for three to four succession sowings split across both windows.

The primary zone 7b adjustment is heat management in spring. Arugula planted in late March or early April benefits from 30% shade cloth once daytime highs regularly reach 70°F, which can extend harvest by two to three weeks before bolting becomes inevitable. Succession sowing every two weeks from late January through mid-March spreads risk and smooths harvest. Downy mildew, the most common disease threat for arugula, intensifies during humid fall conditions. Wider row spacing (8 to 10 inches rather than 4 to 6) and morning irrigation rather than evening reduce humidity at the canopy level. Japanese beetles and brown marmorated stink bugs both feed on arugula foliage during late spring and early summer; floating row cover provides physical exclusion if pressure is heavy. Summer is not a growing window in zone 7b; attempting midsummer plantings in full sun reliably fails.