Tomatoes: Tomato Tips for San Antonio Gardens in March

This week is a tomato week. The date is quickly approaching to get your tomatoes into the garden (we use March 15th as a marker), and I’ve been working on a couple of blogs to increase the chances that you will have a successful tomato harvest this year.

I recently bought the book, ‘The Vegetable Book: A Texan’s Guide to Gardening’, by Dr. Sam Cotner, which was recommended by David Rodriguez, our Bexar County Horticulture Extension Service Agent, at a recent event we hosted. David was right about this book having some great info when it comes to planting vegetables in Texas. I concur with the growing tips highlighted in the tomato section of this book and have paraphrased a few choice sections. Enjoy, it’s tomato season!

Two Tips To Start Tomatoes Off Right

1. Tomato Transplants Over Seeds in March

Choose transplants rather than seeds in March. Tomatoes must bloom before night temps exceed 75° and daytime temps hit 92° and upwards. This usually happens pretty quickly after our last freeze. If you try to direct seed now, your timing will be pretty off. By the time your plant is ready to produce a flower, it may be too hot already, and you may get very few blossoms if any. No blossoms equals no fruit. Tomato transplants are your best bet in March. Lucky for you we still have a great selection. 

2. Grow the Right Tomato Varieties

Now that you know you need to choose tomato transplants over tomato seeds during March, how does that help you know which transplants to choose? No worries; we’ve got you covered. 

Smaller fruiting varieties of tomatoes ALWAYS fare better than large beefsteak options. I know, I know, we love those big ‘maters! That’s why we were encouraging you to start seeds indoors way back in January. And also why we were encouraging you to folow the BBPP method for growing spring and fall tomatoes. Starting early, you can grow your tomatoes in a protected area, so by the time March 15th rolls around, you’ll have a good-sized tomato transplant that is already setting, or about to set, flowers. 

Some people opt to chance it and plant tomatoes that produce large sized fruit anyway. Best of luck to you! San Antonio weather is wild. Maybe those tomatoes will bear fruit, but we have had the best success with small to medium fruiting varieties and cherry/pear/grape types in this area. We bring in all types of tomatoes because we have all types of growers as our customers. We give you the info and let you make your choices. 

6 Planting and Care Tips for Tomatoes

1. Water the garden a couple of days before planting your tomatoes. This will ensure the soil is moist, but not wet. A moist soil allows for tomato roots to easily penetrate and develop, giving your newly planted tomatoes the best welcome home gift!

2. Water your tomato transplants before planting. This is even more important if your tomatoes have been growing in peat. If the peat has been allowed to dry out, it’s somewhat difficult to rewet. (You can soak the plants in a container of water for a few minutes before planting if this is the case.) 

3. Setting Tomatoes in the Garden. CAREFULLY set tomatoes into the garden slightly deeper than it was growing in its pot. Really there are 2 ways of thinking when it comes to how deep to set tomato plants. Some experts say, plant really deep, like up to the first or second set of leaves. Some experts say if you plant really deep, the soil is colder by the roots and it can slow plant growth. Hmmm… in spring, I’d opt for setting plants just slightly deeper than their containers, and in late summer early fall, I’d go ahead and set them even deeper to protect from the summer heat. How’s that for a compromise?

If you end up with extra leggy transplants, you can always lay your tomatoes on the side, and bury the root ball about  2-3 inches under the soil. Yes, people grow tomatoes like this! They are vines after all; tomatoes can even grow sprawling along the ground. However, experience has shown that tomatoes grown upright generally produce more fruits of higher quality.

Don’t bother with tiny, or even small cages, use those for propping up eggplant and peppers. In general, tomatoes are large plants. Medium sized cages are good for patio and miniature tomato plants, but opt for the large and extra large cages for any other varieties. 

4. Feed Tomatoes Right Away. Water in your tomatoes with half strength/diluted water soluble fertilizer. Something with a higher nitrogen number (the first of the 3 numbers found on fertilizer products). You’re going for vigorous vegetative growth right now. 

5. Protect Tomatoes. ALWAYS, ALWAYS have weather protection ready during these early planting weeks. In spring, a late frost always looms possible and frost cloth may be needed. In early fall, the summer sun is still a scorcher, so shade cloth will offer some reprieve.

6. Water Tomatoes Consistently and Properly. Some of the most annoying tomato issues can be avoided if they are just watered properly. Blossom-end rot (also caused by, but not as likely, a calcium deficiency in soil) and fruit cracking are caused by fluctuations in soil moisture. Opt for consistent soil moisture that is neither too wet nor too dry. 

Best ways to have uniform soil moisture:

• Drip Irrigation (Controlled amount of water, water conservation, water delivered straight to the roots)
• Mulching tomato plants (conserves soil moisture, prevents weeds competing for moisture). However, don’t mulch too early as it tends to keep soil cooler in spring. Wait to mulch until after the coolest of our spring weather starts 
• Planting in raised beds (improves drainage)

You should be aiming to wet the soil to a depth of 6-8 inches when you water your tomatoes. Remember, the roots of tomatoes run deep. When drip irrigating, 2-3 hours every other day is generally sufficient, depending on weather/rainfall.

We have a lot more info on tomatoes. You can find out more about different varieties, tomato likes and dislikes, tomato pests, tomato disease, and even a tomato shopping list. Just search ‘tomato’ or ‘tomatoes’ on our website and you’ll have a plethora of tomato options to choose from. Get planting, spring is here!

~The Happy Gardener, Lisa Mulroy

Special thanks to Dr. Sam Cotton for his awesome tomato chapter in ‘The Vegetable Book: A Texan’s Guide to Gardening’ and also to David Rodriguez, Bexar County Horticulture Extension Agent, who recommended it.