Master Gardeners: Tomato Time: Tips for Trying Container Gardening | master gardener


PENNY PAWL UC Napa County Master Gardener

Spring is just around the corner, so it’s time to plan your summer garden. The Napa County Master Gardeners will be offering a wide variety of organic tomato plants for sale on Saturday, April 9. You can pre-order seedlings online ( starting April 3. The varieties were chosen because they are doing well in Napa Valley, with several new varieties available this year.

Have you thought about growing tomatoes in pots? Many people have reported success in doing so. Here are some tips if you want to try it.

First, determine the mature size of the tomato variety so you can choose a pot, bucket or barrel large enough to accommodate the root system. Tomatoes are generally the most rooted plants in a vegetable garden. Additionally, you need a pot large enough for a tomato cage or other supports.

Make sure the container has enough holes for good drainage, as tomatoes don’t like wet roots. If you need to improve drainage, drill ¼ inch holes in the bottom of the pots before adding soil.

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Because soil can wash out of pots, I line the bottom with newspaper before adding soil. Colored newsprint contains clay in the ink, so avoid using it. You can also use the old window screen.

Tomatoes in containers need constant watering. Pot soil dries out quickly. I have found that the soil can be wet on the top of the pot and dry on the bottom. When you water, make sure the water penetrates all the way to the bottom of the pot.

Use a soil rich in phosphorus and potassium. You can buy potting soil from nurseries or mix your own. I usually make mine from a mixture of sandy loam, perlite or red lava rock and compost. Aged chicken manure is a good addition. Aim for a pH. 5.5 to 7.5 for best results.

Once you’ve filled your buckets or pots, you probably won’t want to move them, so be sure to place them in a very sunny area. Tomatoes need sun to be at their best. Put a cage around your tomatoes as soon as you plant them.

You will need to know if the varieties you have chosen are determinate or indeterminate types. Determinate tomatoes are probably a better choice for container growing because they stop growing once the flowers appear. Indeterminate varieties continue to grow even after the flowers appear. If you want to grow tomatoes in a hanging pot, an indeterminate type is probably the best choice.

I once grew a cherry tomato that was still producing late November. It was an indeterminate variety that kept growing, flowering and producing tomatoes that I ate right off the plant.

This year I plan to try an indeterminate cherry tomato in a hanging pot. I see them in garden catalogs. At the end of the summer, I may be able to move the plant to my greenhouse.

If you plant tomatoes in hanging pots, make sure the hanging wires are strong enough to hold the pot while the tomato matures.

Gardening with the masters

Napa County Master Gardeners and Ole Health present a Gardening Class Saturday, March 19 from 10 a.m. to 1 p.m. at Ole Health’s Garden at 300 Hartle Court in Napa. Space is limited. Sign up at


• The Napa County Master Gardeners will be hosting a “Growing Tasty Tomatoes” workshop on Sunday, March 20, 1-3 pm, at the Yountville Community Center, 6516 Washington Street, Yountville. Register online or at or call 707-944-8712 to register.

• The Napa County Master Gardeners will be holding a workshop on “Spring Garden Soil Preparation, Seeds and Seedlings” on Saturday, March 26 from 11 a.m. to 1 p.m. at the Las Flores Community Center, 4300 Linda Vista Avenue, Napa. Register at

Tomato Sale: The Napa County Master Gardeners will be holding their annual Tomato Plant Sale on Saturday, April 9, from 10 a.m. to 1 p.m. or while supplies last, at 1710 Soscol Ave., Napa. Twenty-seven varieties will be available.

Do you have questions about the garden? Contact support. The team is working remotely, so please submit questions via the diagnostic form, sending photos to [email protected] or leaving a detailed message at 707-253-4143. A Master Gardener will answer you by phone or e-mail. For more information, visit


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