UC Master Gardeners, Santa Clara County, CA
University of California
UC Master Gardeners, Santa Clara County, CA

Tomato Tips

Garden Help >Vegetables > Tomatoes

Here's a listing of all our tomato tips. Refer to the UC Pest Site page on tomatoes for more information about caring for tomatoes and the most common problems.

Tomato Tips for All Months

Healthy Tomatoes

Tip description
Tomatoes are one of the most popular vegetables in home gardens, largely because of the taste difference between a homegrown tomato and a store-bought tomato. Here are a few things to watch out for to keep the plants healthy. Regular watering helps nutrients flow throughout the plant and can prevent blossom end rot. Clean soil and sanitation reduce the common Verticillium wilt in which lower and older leaves turn yellow and brown. And russet mite, where lower leaves and stems appear a greasy bronze, can be controlled with sulfur dust.
 
Months applicable
  • July
  • August
Category
  • 3. Pests and Diseases

Late Tomatoes

Tip description

Tomato blossom, by Allen Buchinski
Tomato blossom, by Allen Buchinski
How many more edible tomatoes can you expect to get this year? Any tomatoes currently on the plant are likely to ripen nicely in the next month or so. Current blossoms may lead to good tomatoes, mealy tasteless tomatoes, or none at all. It depends on the weather. Many of us have taken the gamble and eaten tomatoes into December and beyond, more for the challenge and bragging rights than for exquisite flavor. But a cool fall can affect production and quality, and some gardeners start removing blossoms now. This allows the plant’s energy to go into the existing fruit. If we have another mild winter like last year, the plant could survive and produce another crop of tomatoes next summer. We each make our own decisions based on our guesses, hopes, energy level, and available garden space.

More information: Growing tomatoes in the home garden

Months applicable
  • September
Category
  • 1. To-do

Tomato blossom end rot

Tip description

Tomato blossom end rotA brown depression on the bottom of tomatoes is usually blossom end rot (BER). This disorder is related to a calcium deficiency aggravated by irregular watering. Since most soils have adequate calcium, watering is usually the problem. Without regular watering, the calcium in the soil cannot reach the plant. Mulching can help. Water tomatoes regularly. Avoid flooding them so the roots sit in water. For more detailed information about BER please view Managing Blossom-End Rot in Tomatoes and Peppers.

Months applicable
  • July
  • August
  • September
Category
  • 3. Pests and Diseases

Tomato Bottom Scarring

Tip description

Tomato bottom scarring

Sometimes scarring can be seen on the bottom (blossom end) of tomatoes. This can be caused by weather conditions such as cool and cloudy weather at bloom time, making the blossom stick longer to the small fruit. The fruit is perfectly good to eat with the damaged part cut out. Some large heirloom tomatoes are more susceptible to this condition.

Also known as catfacing.

Months applicable
  • June
  • July
  • August
Category
  • 1. To-do

Tomato Hornworm

Tip description
Both tomato hornworms and tobacco hornworms can do significant damage to tomato plants. They can eat entire leaves and take bites out of the fruit. Although they are large with a striking appearance, they camouflage themselves well on plants and can be surprisingly hard to find. Once you see one, you’ll wonder how you missed it. The first clue to their presence is often a pile of frass (insect larva excrement) on the leaves or ground under the pest. They are up to four inches long so they are easy to handpick for disposal. If you see a row of white eggs on their backs, those are from a parasitic wasp that will take care of the problem naturally. They are striking, with white striping and little round circles. The caterpillars get their name from the horn on their back end, and they are the larval stages of rather large brown moths.
 
More information: Tomato Hornworms
 
Months applicable
  • June
  • July
  • August
Category
  • 3. Pests and Diseases

Tomato Russet Mite

Tip description

Tomato russet mites deplete juice from the cells of leaves, stems and fruit. They usually start at the base of the plant and move upward. If not controlled, these pests can kill plants. At first sign of damage, treat with sulfur dust or a spray solution of wettable sulfur and spreader-sticker. More information is found in the UC Pest Note on Tomato Russet Mite.

Months applicable
  • June
  • July
  • August
Category
  • 3. Pests and Diseases

Tomato Staking

Tip description

It's time to start planning how you will stake your tomatoes. You will want to stake your tomatoes right after you plant your seedlings. Here are the various Tomato Staking Techniques we have tried.

Months applicable
  • April
  • May
  • June
Category
  • 1. To-do

Tomatoes and Peppers

Tip description
February and March are when Master Gardeners start seedlings for our annual Spring Garden Market. Tomatoes and peppers need a long, hot growing season, so starting seeds indoors or in a greenhouse in February or March will give them a head start. Put the seeds into small pots with loose potting soil and cover with a thin layer of soil or vermiculite. Keep them moist until they germinate. Keeping them in a warm place, such as by a sunny window or on a seedling heating pad, will help in germination. Provide plenty of light, preferably with fluorescent lighting close to the plants. As they grow and while waiting for the ground to warm up, they can be up-potted to larger pots and gradually introduced to the outdoors. 
 
More Information: Vegetable Gardening
 
Photo: Tomato and pepper seedlings under adjustable-height fluorescent lights, by Laura Monczynski
 
Months applicable
  • February
  • March
Category
  • 2. What to plant

Watering Tomatoes

Tip description

If you haven't already, it's time to cut back on watering tomatoes. Tomatoes have far more flavor when the ripening fruit is deprived of water. Don't forget to remove competing weeds from around the garden.

Months applicable
  • July
Category
  • 1. To-do

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