March in San Diego is the start of the best growing season of the year. Zone 10a gives us something most of the country doesn't have: the ability to grow warm-season crops early while cool-season crops are still producing. Right now, your garden can have both.
🌡️ What to Plant in March
Warm-season crops to start now: Tomatoes, peppers, cucumbers, zucchini, squash, eggplant, and beans can all go in the ground or be transplanted in March. If you haven't started seeds indoors, pick up transplants from your local nursery — it's not too late.
Still going strong from winter: Lettuce, kale, spinach, peas, broccoli, and cauliflower are still producing. Harvest them before the heat hits in May. Once daytime temps consistently reach the mid-80s, these crops will bolt.
Herbs: Basil, cilantro, dill, and parsley can all be direct-sown now. Plant cilantro in succession (every 3 weeks) because it bolts quickly in San Diego's warmth.
🐛 Spring Pest Watch
San Diego's mild winters mean pests never fully die off. Here's what to watch for right now:
A strong blast from the hose handles most aphid problems. For cabbage worms, floating row covers are your best friend. Our full organic pest guide has prevention and treatment for all 35 common garden issues.
☀️ The Heat is Coming
San Diego spring means warm days and cool nights — perfect growing weather. But by late April, afternoon sun can stress cool-season crops. Consider:
- 30-50% shade cloth over lettuce and spinach beds
- Deep morning watering (not evening) to prevent fungal issues
- Mulching beds with 2-3 inches of straw to retain moisture
🌱 Need Help?
If you're in San Diego and want help turning your backyard into a productive garden, HarvestLoop offers garden design, bed installation, and ongoing care. We handle everything from soil to harvest.
Or plan your garden yourself using our free tools: