Tomato Growing Tips
The following information contains tips for growing tomatoes in Contra Costa County.
Terms
- Determinate —This type of tomato stops growing at a set height of about 3-5’ and will bear most fruit within a 4-6 week period. These early ripening types may be best for containers.
- Indeterminate —This type continues to grow and set fruit all summer until killed by frost or disease. Many of the commonly grown larger-fruited varieties are indeterminate.
- VF—resistant to Verticillium wilt and Fusarium wilt (common fungal diseases)
- VFNT—same as above, plus resistant to nematodes & tobacco mosaic virus
Which Variety
Choose varieties that fit your microclimate and space requirements. Tomatoes generally need heat to develop well, but there are varieties that will grow in the cooler parts of Contra Costa County that experience a strong marine influence.
Click here for some suggested varieties.
When to Plant
Plant in late spring or early summer after nighttime and soil temperatures have warmed up.
Light
Full Sun. Select a planting site that will provide a minimum of 6 to 8 hours of direct sunlight per day.
Soil
The annual addition of several inches of aged organic matter to your soil will greatly improve plant nutrition and foster appropriate moisture retention. Dig humus, compost, or well-composted manure into the top foot of soil and allow it to sit for at least a week before planting.
How to Plant
Roots will form along the buried portion of the stem, giving better growth and less chance of injury from a stem that is too weak. Lanky young plants can be buried right up to the first leaves or even horizontally in the ground. Allow several feet between plants for good air circulation. Only grow tomatoes in the same spot for a maximum of 2 years in a row. Rotate with other crops from a different plant family to help prevent disease buildup in the soil. Tomatoes, peppers, eggplant, and potatoes are all in the same plant family—the Solanaceae.
Support
Tomatoes of all types need strong support, such as a trellis, cage, or stakes, to keep plants upright. This will save space and allow easy harvesting. Plants that touch the ground are more susceptible to diseases. You may prune out some side shoots to keep plants in bounds.
Water
Keep the soil moist around new plants for the first 3-4 weeks. Water established plants when the soil is dry to about 2-3”. Tomatoes need regular irrigation during the growing season. Avoid extreme fluctuations in moisture, as they increase the incidence of fruit cracking and blossom end rot.
Fertilizer
Healthy, vigorous plants should not require extra fertilizer until they have set fruit. Excessive nitrogen fertilizer during the initial growth period will cause a flush of vegetation that may delay flowering and fruit set. After plants have set fruit, you may want to fertilize with nitrogen every 4 to 6 weeks. Follow label directions and avoid over-fertilizing, as excess flows into the groundwater and eventually into the San Francisco Bay.
Information Sources
Free, downloadable publications from UC Agriculture & Natural Resources:
- Publication 8159: Growing Tomatoes in the Home Garden [External link NOT FOUND]
- Publication 8059: Vegetable Garden Basics [External link NOT FOUND]
Common Tomato Disorders
Here are some of the more common tomato disorders that result from nonliving (abiotic) causes, often attributable to environmental or cultural factors, or simply to the plant’s genetic makeup.
Problem: Blossoms fall off, and the plant fails to set fruit.
- Probable Causes: Night temperatures too low(below 55° F), daytime temperatures too high (above 90° F), excessive smog, excess nitrogen fertilizer, too much shade, plants set out too early in spring, and/or poorly adapted variety.
- Control: Hormone sprays (from garden centers) can improve fruit set during low temps, but not high temperatures. Tapping on blossom stems 3 times a week when blossoms are open at midday may improve pollination and help set fruit.
Problem: Yellow or yellow-orange-colored fruit instead of normal red.
- Probable Causes: overexposure to sunlight.
- Control: Maintain plant vigor to produce adequate leaf cover. Avoid over-pruning. Provide partial shade (i.e., shade cloth) during the hottest part of the day.
Problem: Older leaves suddenly roll upward and inward and become stiff, brittle, and leathery.
- Probable Causes: High light intensity and high soil moisture, particularly when plants are heavily pruned. Some varieties are more susceptible.
- Control: Maintain even soil moisture, provide shade during the hottest part of the day, or try a different variety.
Problem: Blossom End Rot—a water-soaked spot on the blossom end of fruit enlarges and darkens, becoming sunken and leathery.
- Probable Causes: Calcium and water are out of balance in the plant, aggravated by high soil salt & fluctuating soil moisture.
- Control: Maintain even soil moisture, add organic matter to improve water retention, and avoid heavy applications of nitrogen fertilizer. Soils deficient in calcium may be amended with gypsum.
Problem: Puffiness—a tomato resembles a bell pepper with normal outer walls and a hollow area inside.
- Probable Causes: Temperatures that interfere with pollination, such as above 90 degrees or below 55 degrees; low light; excessive nitrogen fertilizer; and heavy rainfall (causing bees to stay home).
- Control: Avoid heavy nitrogen fertilizer and select varieties suitable for your microclimate.
Problem: Catfacing—circular concentric cracks around the stem end, cracks radiating outward from the stem, malformation, and cracking at the blossom end.
- Probable Causes: Periods of fast growth with high temperature and high soil moisture, wide fluctuations in soil moisture, and wide differences in day and night temperatures. Some varieties are more susceptible.
- Control: Keep soil evenly moist, maintain good leaf cover, or provide shade during the hottest part of the day, apply organic mulch 3-4 inches deep to moderate soil temperature.
Besides these common abiotic disorders, gardeners often discover damage to foliage and fruit caused by a variety of pests, including hornworms, fruit worms, pinworms, stink bugs, whiteflies, and leaf miners.
Resources
- For photographs and information to help you identify and manage pests, refer to the UC Integrated Pest Management for Tomatoes.
- For specific pests, see the UC IPM Pest Notes. Or, contact the UC Master Gardener Program in Contra Costa for assistance. To reach the Help Desk, call (925) 608-6683 or email ccmg@ucanr.edu.
From PDF article dated 2020-02-22
UC Master Gardener Program of Contra Costa County
2380 Bisso Lane, Concord, CA 94520
Website: https://ucanr.edu/site/uc-master-gardener-program-contra-costa-county