Edible Gardening Series: Question of the Week – growing tomatoes in containers
By Sarah Bostick and Carol Wyatt-Evens
Gardening in Florida can be incredibly rewarding and incredibly frustrating, at the same time. If you are new to the region, you soon learn that gardening in the Sunshine State can quickly become a full-time job. While our subtropical climate is perfect for growing an abundance of different vegetables, fruits, and herbs, it also can present some overwhelming challenges.
We can help! UF/IFAS Extension Sarasota County agents and staff have created an online edible gardening resource center. The website features short videos from our 25-episode “Edible Gardening Series” webinars, along with blog posts and resources lists for episodes. Get help on an array of topics that befuddle many gardeners.
This week’s Question of the Week is:
Growing Tomatoes in Containers
We are doing our blog posts a little differently this week! Rather than focusing in on one topic, we are answering all of the questions asked our Tomato 101 class in a series of four themed blogs. Here is a Q&A for the “Why won’t my tomatoes produce fruit?” theme:
Q: What is the best tomato to grow in a container in central Florida?
A: There are two categories of tomato: determinants and indeterminants. Determinant tomatoes are relatively short, stocky, bushy plants. Indeterminants are long, sprawling plants that require very sturdy support structures to support their non-stop growth. In general, determinant varieties of tomatoes do better in pots and other containers. Tomatoes grown in containers are not as stable as tomatoes grown in the ground and will benefit from being staked or caged.
Here is a University of Florida publication of tomato varieties that do well in Florida. It is organized into varieties that do well in the northern part of the state and varieties that do well in the south and central part of the state.
Q: What do I need to know about growing tomatoes in containers?
A: Most tomato varieties want to grow to be BIG and that means that they need a big container to achieve their full size and health. A good rule of thumb is that most tomatoes need a container that is no smaller than 5-gallons. Some tomatoes have been bred to thrive in much smaller containers, such as hanging baskets. In general, the more space you provide for a tomatoes root system, the happier, healthier, and more productive that tomato will be.
For a number of reasons, it is best to use potting mix in containers rather than soil from the backyard. One of those reasons is that that soil tends to become very compacted and water-logged in containers. Potting mixes are special blends that prevent compaction and water logging. You do not need a special tomato potting mix. When you choose a potting mix, be sure to thoroughly read the bag before adding fertilizer. Some potting mixes contain fertilizer and others do not.
Q: Can you reuse the soil that contained last year’s crop again this year?
A: In general, it is a much better idea to start fresh with new soil each year. Tomatoes are very susceptible to a wide range of diseases and many of those diseases live in the soil – and remain in the soil for many years, just waiting for another tomato plant to infect. If want to re-use last year’s potting soil, it is best to either grow something from a different plant family in the soil or sterilizing your soil. Tomatoes, peppers, eggplant, and potatoes are all in the same plant family, so choose something other than these four plants to grow in re-used potting soil.
There are many DIY instructions you can find on the internet for sterilizing potting soil. Most involve putting about 2-inches of moist potting soil on baking sheets and cooking the soil at about 160 to 180 in the oven for around 1 hour. This will kill many, but not all tomato diseases.
Q: Can I solarize my soil from a self-watering planter box or big pot?
A: Solarization is a technique for using the heat of the sun and a big sheet of plastic to cook the microscopic pests and diseases in soil, rendering the soil mostly sterile. This technique is often used on raised beds and gardens with major nematode pressure. (Curious to learn more about nematodes? Check out this Edible Gardening Series Question of the Week blog post on nematodes. Interestingly, there seems to be very little information about solarizing soil in planter boxes! This would be a great citizen-scientist experiment. Here is a simple guide to solarizing your garden.
For answers to more common tomato questions, click on the links below:
- Tomato-growing aids: trellises, plastic mulch, and other products
- Tomato troubleshooting: why won’t my tomatoes produce fruit?
- Growing tomatoes in containers
- What do I need to know about tomato seedlings: planting dates, transplant size, and disease resistance?
The Edible Gardening Series and blog series is a partnership between the following UF/IFAS agents and Sarasota County staff:
- Sarah Bostick, Sustainable Agriculture Agent
- Carol Wyatt-Evens, Chemicals in the Environment Agent
- Mindy Hanak, Community & School Gardens Educator
- Kevin O’Horan, Communications Associate