Arugula is a fast-growing cool-season salad green – often ready to harvest just 4 weeks after seeding. It prefers rich soil with a pH of 6 to 6.8, but it tolerates a wide variety of conditions.
Seeds germinate quickly even in cold soil. Plant as soon as soil can be worked in spring. Avoid planting after other cabbage family crops. Plant ¼ inch deep and 1 inch apart in rows, or broadcast alone or mixed with other greens. Gradually thin to 6-inch spacings using thinnings for salads. It forms a rosette of deeply lobed leaves. Plants become erect when heat induces bolting.
Succession plant for every 2 to 3 weeks for a continuous supply until about a month before your average first frost date. Good plant for intercropping.
You can slow bolting by reducing heat with shade and avoiding moisture stress with regular watering. Arugula often self-seeds. It requires insects for pollination and will not cross with other members of the mustard family.
To harvest Arugula, pick off the outside tender leaves at the base of the plant. Leave the center growing point for future harvesting. Larger leaves tend to get tough and very bitter tasting so harvest them small. Hot weather will also make the leaves bitter.
Arugula, Eruca sativa
Pollination, insect; Life Cycle, Annual; Isolation Distance, 1/2 mile
Arugula is self-pollinating, but will also cross-pollinate (possibly even between different species). Further, wild arugulas are common in most areas worldwide. Individual flower heads can be bagged to allow growing several varieties in proximity or to ensure that wild plants don't cross the plants you're growing. Collect the seed heads as they dry on the plants and store in closed paper bags to finish drying (many of the seeds will shed naturally). Don't let the seed heads get wet after they dry. Chaff easily blows away after seed heads are crumbled—watch for thorns or prickles in some plants!