Tomatoes With Curled, Gnarly Leaves?

When gardening fever strikes, most folks test their skills with tomatoes first. The Garden Writers Association Foundation estimates that more than 41 million U. S. households grew a vegetable garden in 2009. That’s 38% of households in the U. S. They also estimate is that tomatoes are grown in 85% of those gardens.

With home gardeners, also known as hobby gardeners, tomatoes are the hands down favorite, followed closely by cucumbers and peppers. The naïve, uninitiated gardener buys a tomato plant in a peat pot at the local big box store or retail nursery, digs a hole, fills the hole with potting soil, fertilizer and water, then sits back and waits for the bumper crop of tomatoes to grace his kitchen.

Most novice gardeners overwater and over fertilize their plants. If a little water is good, then a lot of water is great! High nitrogen fertilizer will grow their plants quickly according to the not-so-experienced sales person at the big box store. So the new gardener follows the sales person’s instructions and thoroughly waters his tomato plants each day, and applies a high nitrogen fertilizer each week or so.

At first the results are incredible. The plants shoot up quickly and put forth deep green leaves. The excited garden novitiate is pleased with his results and thinks “It ain’t so hard to grow vegetables”. He promises himself that next year he will plant more…maybe even do so later this summer, so he can have fall tomatoes.

Then one morning, he goes to visit his tomato plants and finds that some of the new, tender leaves are a pale yellow starting at the leaf stem and moving up into the veins of the new leaves. The store sales person told him that the nitrogen fertilizer would make the leaves “green up”. So the hobby gardener thinks if they are yellow they must not be getting enough fertilizer. He mixes up a batch of Miracle Gro, adding more than the recommended amount of the fertilizer and waters the tomatoes until the water-fertilizer mixture creates rivulets as it runs off the soil around the plants.

Two days later he checks his tomatoes again. He is horrified to find that even more leaves are yellowing and the new growth doesn’t even look like leaves. The new growth looks like spindly little shoots that are not forming leaves at all. And when the new growth does look like a leaf, it is curled and gnarly, reminiscent of what herbicides do to unwanted weeds. Of course, to correct the situation, he adds more water.

Do you see a pattern forming here? I hope you do, because this is one of the most common experiences for the new tomato grower: over watering and over fertilizing. If this practice continues, the plants will be stunted, produce few if any tomatoes and will expire early. The novice gardener will say he has a brown thumb and will never attempt to garden again.

This gardener’s anguish and the early demise of his precious vegetable plants could have easily been avoided by using a soil moisture meter. These devices range in price from five dollars to a couple hundred dollars. Digital versions in the $12 to $25 range are entirely adequate for the hobby gardener. There are a number of manufacturers and the moisture meters are available online or at your local big box store…the same place you bought your tomato plants in the first place!

The cheaper ones are entirely satisfactory and will give a reading from 0.0-10. A low reading (0.0 – 1.5) indicates very dry soil that should watered immediately. A reading near the top end of the scale (9.0 – 10) indicates a very wet soil that should be allowed to dry out significantly before adding more water. Most vegetable plants should be maintained in the 2.5 to 5.5 range for optimum growth and production.

Get yourself a moisture meter, avoid those curled and gnarly leaves on your tomatoes, and enjoy one of Nature’s very best homegrown fruits.