It began in mid-February during the first sunny weekend, and picked up speed in March: the appearance of summer vegetable plants, at the big box stores and large chain stores throughout Northern California. March (and early April) is still too early for many of the heat loving vegetables to be thrust into the ground, unprotected. Soil temperatures in the area are still in the high 40's-low 50's, too cold for tomato and pepper plants to put on any active growth. And the less active the growth cycle, the less ability the plant has to stave off insect and disease problems. This is why many independently owned nurseries and garden centers don't start bringing in the summer vegetables until spring: the plants stand a better chance of survival in the backyard garden.
Of course, all gardening is local. One way to determine the best time to plant your summer vegetable garden:
Sit in the garden bed for 60 seconds, pants off. If you can stay there, comfortably, go ahead and plant.
• Build a tall fence or plant tall shrubs first.
• Have a hose ready for the ants.
For the fearful and fenceless among you, get a soil thermometer.
SOIL TEMPERATURES FOR VEGETABLE SEEDS
Average Soil Temperatures/2009-2010/Mid-Month Readings
Four-Station Valley Averages (Sacramento, San Joaquin, Yolo, Sutter Counties)
(Soil temperature readings (F) taken 6" deep)