Arugula is a delightful, peppery salad green that does exceptionally well in the temperate climate of California. Known for its quick growth cycle, arugula can be harvested as soon as 40 days after planting, making it an ideal crop for both home gardeners and commercial growers. With the right timing, you can enjoy fresh arugula from your garden throughout the cooler months, particularly if you understand your local frost dates, such as the median last spring frost of January 31 in Zone 8b–9a.
To make the most of your arugula, it's essential to plant it during the optimal times based on frost dates. For many regions in California, this means starting your seeds indoors in late winter to be ready for spring planting. Consider that the first fall frost typically arrives around December 4 for Zone 8b–9a, which gives you a long growing season to work with. This lettuce alternative not only adds flavor to your salads but is also versatile in various culinary uses.
The key to a successful arugula crop lies in timing and consistent sowing practices. By planting your seeds 4–6 weeks before the last frost, you can stagger your harvest and keep your kitchen stocked with this robust green all season. Additionally, with arugula's propensity to bolt in warmer weather, planting in the right intervals will help extend your harvest and make your garden more productive.
| Zone | Indoor start | Transplant out | Direct sow | Harvest |
|---|---|---|---|---|
| Zone 8b–9a | Start January 1 – January 15, ~4–6 weeks before January 31 | Transplant outdoors February 15 – March 1, as soil warms | Direct sow March 1 – March 15 for spring harvest, September 1 – September 15 for fall | Harvest from mid-April through late June and September to November |
| Zone 7b–8a | Start January 15 – February 10, ~4–6 weeks before February 26 | Transplant outdoors March 10 – March 20 for a spring crop | Direct sow March 15 – April 5 and again August 15 – September 5 for fall | Harvest from early May through late June and again October to November |
| Zone 9b | Start December 1 – December 15 for a late winter crop | Transplant outdoors December 20 – January 5 | Direct sow January 5 – January 10; no fall planting needed | Harvest from January through early May |
If you're in a colder region of California, such as higher elevations or coastal areas, be cautious with planting dates. Use row covers to retain heat after you transplant outdoors to protect arugula from unexpected cold snaps.
While planting arugula in May is not ideal, particularly in warmer zones, you may succeed if you choose a shaded location and ensure consistent moisture. Be prepared for the possibility of quick bolting as temperatures heat up.
You should begin harvesting arugula when the outer leaves reach 3–4 inches tall. Keep an eye on the plants, as they can bolt quickly when temperatures rise, leading to bitter leaves that are less appealing.
If you notice your arugula starting to bolt, quickly harvest the remaining leaves to prevent further bitterness. You can also let one plant go to seed for self-sowing. Monitor temperature and shade your crop in extreme heat.
Yes, flea beetles can be a significant issue for arugula. These tiny pests create noticeable damage on the leaves. Use floating row covers early in the season to prevent infestations and keep your plants healthy until harvest.
Typical fall sowing window for Arugula in California: October 7 – October 28.