Time of planting

California has a unique vegetable growing climate, we can grow many different types of vegetable crops throughout the year. Crops are classified as warm-season or cool-season crops. Vegetable planting guides provide the approximate planting periods for both cool and warm-season crops. If they are planted too early or too late, productivity will be reduced. It is important that you plant at the right time of year for each crop for optimum yield.

Temperature is probably the most important climatic factor that affects the success of your garden.

• Cool-season crops grow best and produce the best quality when the average temperatures are 55°F to 75°F and are usually tolerant of slight frosts. Plants in this group include root crops such as: beets, carrots, parsnip, radish and turnips; stems such as asparagus and white potato; leafy crops such as cabbage, celery, lettuce, onion, and spinach and plants whose immature flower parts we eat, such as broccoli, cauliflower, and globe artichokes.
  
  
• Warm season crops are crops that grow best when the days are long and hot (between 65°F and 95°F. These include crops with mature fruit such as tomatoes, cantaloupe, winter squash and watermelon, or immature fruit such as corn, squash, and snap beans.

Other climatic factors that affect the growth and quality of vegetables are soil moisture and length of day from sunrise to sunset. For example, brussel sprouts and globe artichokes grow more successfully near the ocean, where the humidity is high and temperatures are cool. Many annuals, such as radishes, lettuce, spinach, and Chinese cabbage, tend to produce flowers as the days grow longer in late spring.

Be aware of both the approximate first and last frost dates in your area and protect plants if frost is expected. (unless crops are frost tolerant). You can expand your growing season by starting plants indoors 6-8 weeks prior to the date you want to plant the garden.

Recommended planting dates for major regions of California

These dates are based on the average temperatures for each region; you may have to make some adjustments if your area varies widely from the average. Seasonal temperatures are very important in determining when to plant a crop so that it matures when average temperatures are likely to be optimal.

Notes: North and North Coast = Monterey County north; South Coast = San Luis Obispo County south; Interior Valleys = Sacramento, San Joaquin, and similar valleys; Desert Valleys = Imperial and Coachella Valleys. Planting dates are for seed unless noted otherwise. Because the areas shown here are large, planting dates are only approximate, as the climate may vary even in small sections of the state. Contact experienced gardeners in your community and experiment on your own to find more precise dates.

*Transplants, shoots, or roots are used for field planting.

Source: California Master Gardener Handbook, Table 13.2, Adapted from Vegetable Gardening Illustrated 1994.