Master Gardener: Tips to know before growing tomatoes | Home & Garden

Tom Ingram Ask a Master Gardener

I am new to gardening, and I want to start growing some vegetables. I was thinking of starting with tomatoes in containers. Any suggestions? — SC

It’s not surprising that you want to start with tomatoes since tomatoes have to be the No. 1 crop for home gardeners. However, there are so many different types, it can get confusing. Let’s declutter the thought process on growing tomatoes a little bit.

When selecting which variety of tomato you want to grow, the first decision you likely will need to make is whether you want to grow determinate or indeterminate tomatoes. Determinate tomato varieties produce a single crop, usually all at the same time. After they have produced this crop of fruits, they are done. Indeterminate tomatoes continue to produce fruit all season.

Determinate tomatoes are good if you plan on canning your tomatoes or making a bunch of salsa to enjoy the rest of the year. Indeterminate varieties provide you with tomatoes for most of the growing season, maybe slowing down a little bit in the dog days of summer, but then picking up again until fall. If you really like tomatoes, plan on growing some of each.

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Next up on the decision tree will be deciding between heirloom and hybrid tomatoes. Heirloom varieties are those that have remained essentially the same for many years. These have seeds that were passed down from generation to generation. Hybrid tomatoes have been cross-bred to help increase production or perhaps increase disease resistance. Seed packets will have a variety of codes on them indicating resistance to certain diseases in tomatoes.

If you want to increase your chances of success as a beginning gardener, maybe go with the hybrids for now and then graduate to the heirlooms as you gain more experience.

Tomatoes are a sun-loving plant, so be sure you have a location where they can receive 8-10 hours of sun per day. You can still grow tomatoes in locations with six hours or so of sun, but your plants won’t be as robust as they would have been in full sun. Also, a little protection from the late-afternoon cooking sun is always a good idea.

If you are going to grow your tomatoes in a container, make sure to fill with a high-quality garden soil. And don’t forget to put drainage holes in the bottom of your container so your plants won’t suffer from root rot.

Tomatoes do best with a fertilizer that is low in nitrogen, so start them out with a little sprinkle of 10-20-10 or a similar fertilizer, about a tablespoon per plant. This amount of fertilizer will not carry them through the growing season, so plan on adding about 2 tablespoons per plant when the first fruits are about one-third grown, then again about two weeks after the first fruits ripen and then again about a month later . Water the plants thoroughly after fertilizing.

When deciding how many tomato plants to grow, a good guide is about three to five plants per person if you are wanting fresh fruit season long. If you are wanting to can or process your tomatoes, five to 10 plants per person is a good guide. All this depends on how many tomatoes you want your plants to produce.

Spacing of your tomato plants is critical and varies with variety. When growing tomatoes in a container, give each plant some space. When planting in the ground, 2-4 foot spacing is recommended.

Most tomato plants will need some type of support, and there are a variety of ways to accomplish this. Most of us are familiar with the standard tomato cages. Tomato cages work best with determinate tomato plants since they tend to be bushier. In contrast, indeterminate tomato plants can get 4 to 6 feet tall, and cages of this size can get expensive. A staking system of some sort works well for these large indeterminate tomato plants. We have a video on the Vegetable page of our website ( that goes into a variety of ways to stake tomato plants.

Water is something else you need to stay on top of with tomatoes because they can easily get stressed when they don’t get enough water, and stressed plants are more susceptible to disease and other growing challenges. During May and June, plan on giving your plants at least 1 inch of water per week and then in July, August and September, increase that to at least 2 inches of water. This will vary depending on your growing location and soil conditions, but tomatoes will tell you pretty quick when they need water, so try not to stress about it.

If you follow these tips, you’ll be well on your way to enjoying tomatoes all season long — unless, of course, you planted a determinate variety; then you’ll have a great crop all at once. See you in the garden!

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You can get answers to all your gardening questions by calling the Tulsa Master Gardeners Help Line at 918-746-3701, dropping by our Diagnostic Center at 4116 E. 15th St. or by emailing us at


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