Growing arugula in zone 6b

In zone 6b, direct sow arugula outdoors as soon as soil can be worked in spring, typically 4 to 6 weeks before the average last frost date (mid-April in most of the zone). Germination occurs at soil temperatures as low as 40°F. First harvest typically comes 35 to 45 days after sowing, putting peak spring production in May.

As temperatures climb toward 70°F and above in June, arugula bolts and turns sharply bitter. Sow a final spring succession no later than late April. Resume in late August for fall production, targeting harvest through October and into November. Light frosts (28 to 32°F) slow growth but do not kill established plants; a row cover can extend fall harvest by two to three weeks past the zone's average first frost.

Zone 6b growers lose the summer months to heat-induced bolting, so timing successions tightly around that window is the main adaptation. Shade cloth (30 to 50 percent) can extend the spring harvest by a week or two when a heat spike arrives unexpectedly, but it is a stopgap, not a solution.

Downy mildew pressure peaks during wet, cool stretches in spring and fall, exactly when arugula is most productive. Improve airflow by thinning to 4 to 6 inches between plants and avoiding overhead watering in the evening. Wild Rocket / Sylvetta shows somewhat better field tolerance to downy mildew than standard arugula, though no widely available variety is fully resistant. Stink bugs, noted as a zone challenge, can damage arugula leaves in late summer and early fall; row covers used to extend the fall season also provide a physical barrier against them.