Published on 05/21/03

Get inside the mind of a garden tomato

By Wayne McLaurin
University of Georgia

In your garden, you need to get inside the mind of a tomato.

No, I'm not crazy. Tomatoes really do think. Well, OK, "respond" might be a better term.

Take, for instance, when the tomato is young. Just planted, with snug roots down in nice, rich soil, plenty of food for growth and nothing to do but just stretch those cells, make chlorophyll and enjoy itself, the tomato is much like a baby. It inches up, extending its roots and growing branches and leaves, then more leaves.

Tomatoes go through growing stages

After going through these juvenile growing pains, it becomes a strong, healthy plant and turns to reproducing its own kind. Its ample leaf area can support reproductive structures (tomato fruits).

Now, at its peak, it sends out the flower structures. The flowers develop, open up for only one day and are pollinated by the wind. The plant sets fruits, knowing all systems are functioning fully, thinking all along just how happy it is in the sunshine.

Along comes a heavy-handed gardener with the fertilizer bag. You know what happens. The gardener sees the plant's flowers and initial tiny tomatoes and, thinking it needs feeding at this reproductive time, dumps a generous amount of fertilizer at the base of the plant.

Fertilizer shock

Almost at once the plant is thrown into confusion. This happy tomato that was basking in the warm sun just a few minutes ago, with no cares in the world, is jolted back into another physiological process it didn't really want.

All of its sensors, all of its "mental" processes, now tell it more fertilizer is present, especially nitrogen, and it needs to throw off the fruit it has set and grow more foliage. The obedient plant responds and drops the fruits.

The gardener goes out the next day and looks for the flowers that were there yesterday, can't find them and calls the nearest county agent.

Well, I get the call from the county agent. That's when I "get into the mind of the tomato." What went wrong from the tomato's perspective?

Tomato care tips

What can you do if you can't think like a tomato? Just follow these directions (that a tomato "told" me):

1. Fertilize and lime according to soil-test recommendations. Use a fertilizer with a 1-2-3 or 1-2-2 analysis (5-10-15, 1-2-2 or 6-12-12, for instance). Avoid, at all cost, using a 1-1-1 analysis, such as 10-10-10 or 13-13-13.

2. Water as needed, usually about 1 inch per week. Don't wet the foliage -- this causes diseases.

3. Side-dress tomatoes only after fruit set and never while they're blooming. It's best to side-dress when the fruits are about the size of a dime. This will allow for proper growth and fruiting for the next flowering structure.

If you talk with your tomatoes, they may tell you,

"More than 100 diseases and insects attack us. So please don't complicate our lives with extra fertilizer and overtax our 'thinking' processes."

Wayne McLaurin is a professor emeritus of horticulture with the University of Georgia College of Agricultural and Environmental Sciences.