Poor Root Development

by Therese
(Casper, Wyoming)

When I pulled my tomato plants this fall, I was surprised to find that the plants have very little root development. Some had only a six-inch diameter spread. In contrast, the tomatoes that are grown in my pots had a sixteen-inch spread side to side and top to bottom. Any suggestions about why my plants in the garden didn't develop deeper root systems?

Tomato Dirt responds
There could be several reasons why your tomatoes didn't develop strong root systems.

One big reason could be inappropriate watering.

Shallow watering. If you water superficially, a tomato's roots don't have to work too hard to reach down into the soil and find water. To help roots develop, water deeply but less often. In the height of the summer, water tomatoes 2-3 times a week. Let water sink into the ground to help plants develop strong root systems. When the soil surrounding your tomato plant is moistened 6-8” deep, you’ll know you’ve done your job well.

In contrast, your container tomatoes have a limited area into which extend their roots. Pots dry out easily, even when watered frequently. Roots work hard to find water, even reaching down and out to fill the pot.

Overwatering. Too much of a good thing isn't! Excess water can choke roots. Then roots stop growing and simply work hard to survive rather than drown. Make sure you plant tomatoes in well-drained soil. Add extra compost to your tomato patch before setting out plants.

Learn more about watering tomato plants.

Another reason your tomato's roots may be struggling is poor soil.

Soil preparation. Make sure you prepare your tomato patch properly. Select an area that is well-drained or even slightly elevated. Raised beds are a favorite among tomato gardeners. Warm the soil so that plants don't need to struggle to survive in cool spring temperatures. Work the area 8-10 inches deep, adding a couple of inches of compost. Test the soil pH. (Tomatoes prefer slightly acidic soil with a pH between 6.5 and 7.0. Amend the soil accordingly!) You can buy an inexpensive pH test kit and test the soil for yourself. The same is true for pH test kits. They are readily accessible online.

A well-prepared bed and healthy soil will allow your tomato plants the best chance at developing strong root systems. Read more about bed preparation.

Pruning and de-flowering. By pinching off flowers on new plants and pruning a tomato plant's suckers early in the season, you can help the plant direct its energy to root and leaf development. Get more pruning tips.

Happy Gardening!

Your friends at Tomato Dirt