As the days grow shorter and temperatures cool in Southern California, our gardens require a transition as well. Warm-season plants are exhausted by autumn after months of growing. Tomatoes stop producing flowers, cucumber vines wither, and pepper plants look blighted. It’s simply the end of their season, and the kickoff of the season for plants that thrive with dimmer, shorter amounts of light and chillier temps. In the cool season, we welcome greens and bulbs.
San Diego County contains USDA Growing Zones 10 and 9, areas with differing average annual minimum winter temperature. Coastal San Diego, from La Jolla to Imperial Beach, is Growing Zone 10b with a higher average temperature. The majority of San Diego is Zone 10a. West of El Cajon and Santee sits the desert and lower temps Zone 9.
Growing zones matter because they give suggestions on the ideal planting time. For example, Zones 9 and 10 have two basic seasons (hot and cool), but Zone 5 in Nebraska has a single growing season of April to October. Double check what zone you’re in by entering your zip code at the USDA website.
You can plant these cool season crops any time during the suggested months. However, try to plant the larger vegetables early to give them the whole season to mature and produce (broccoli, cabbage, cauliflower). Lettuce has a quick growing time, so we plant successions of them all winter.
When “refreshing” a bed, pull the spent plants (and if possible, compost them!) and fertilize the bed with organic vegetable fertilizer. We don’t recommend any fertilizer with a high nitrogen count (anything with double digits) because this creates an unnatural amount of quick, weak growth.
Try not to tread on the bed and avoid massive soil turnover in order to maintain the health of the soil ecology that’s built up in the warm months.
Direct-seed beets and carrots into the soil. Plant older seedlings of brassicas (kale, broccoli, brussel sprouts) to ensure the strongest plants possible.
Adjust irrigation settings to accommodate for less daylight and fewer scorching days. Turn off your irrigation during a rainy day, but don’t forget to turn it back on!
San Diego’s winter crops are fun because they need less daily care, mostly are unaffected by pesky root-knot nematode, demand less fertilizer than summer crops, and often produce constantly. Enjoy the season of salad greens!
Beets: Sept – May
Broccoli: Sept – Feb
Brussel Sprouts: Sept – Nov
Cabbage: Sept – Feb
Carrots: Sept – April
Cauliflower: Sept – Feb
Chard: Sept – June
Garlic: October – Nov
Kale: Sept – April
Lettuce: Sept – April
Onion, bulbing: Oct- Dec
Onion, green: Sept – May
Peas: Sept – March
Potatoes: Feb – March