It
begins every year in mid-February during the first sunny weekend, and picks up
speed in March: the appearance of summer vegetable plants, at the big
box stores and large chain stores throughout Northern California.
As farmers are very aware, March is still too early for many of the heat loving vegetables to be thrust into the ground, unprotected in the northern Central Valley. 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 farmers, as well as many independently owned nurseries and garden centers, don't start summer vegetables until spring: the plants stand a better chance of survival in the bare soil.
More and more farmers are turning to high tunnels, large unheated polypropylene-covered greenhouses for protection and a jump on the planting season for their vegetable starts. "High tunnels become a grower’s insurance policy against high winds and storms, insect infestations and countless plant diseases that can decimate field crops," explains Richard Chamberlain of Harris Seeds. "Inside the high tunnel you will find a controlled environment, much like any greenhouse, except for the fact that the high tunnel is not heated. In addition to protecting plants from Mother Nature’s wrath, it also serves as a season extender, and this is probably where the greater value lies. Growers can harvest crops earlier in the spring and later in the fall, when produce prices tend to be much higher."
As farmers are very aware, March is still too early for many of the heat loving vegetables to be thrust into the ground, unprotected in the northern Central Valley. 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 farmers, as well as many independently owned nurseries and garden centers, don't start summer vegetables until spring: the plants stand a better chance of survival in the bare soil.
Of course, all growing is local. Farmers in Southern California's warmer Imperial Valley and the southern Central Valley can plant processing tomatoes as early as late January into the fields.
If you are of a frugal mind, one way to determine the best time to plant heat-loving vegetables, including tomatoes, squash, corn and peppers:
If you are of a frugal mind, one way to determine the best time to plant heat-loving vegetables, including tomatoes, squash, corn and peppers:
Sit in the garden bed for 60 seconds, pants off. If you can stay there, comfortably, go ahead and plant.
Some tips:
• Build a tall fence or plant tall shrubs first.
• Have a hose ready for the ants.
SOIL TEMPERATURES FOR VEGETABLE SEEDS
Average Soil Temperatures/2010-2011/Mid-Month Readings
Four-Station Valley Averages (Sacramento, San Joaquin, Yolo, Sutter Counties)
(Soil temperature readings (F) taken 6" deep)
January: 48
February: 50
March: 52
April: 57
May: 63
June: 69
July: 74
August: 73
September: 70
October: 64
November: 58
December: 49
