Every two weeks, Chris Riggs sends leaf samples of strawberries, tomatoes — virtually anything he's growing at the time — to the North Carolina Department of Agriculture Laboratory in Raleigh for petiole analysis.

“They analyze the leaves and send the information back to me,” Chris says. “You can look it up on the Internet two days before it gets to me in the mail.”

The North Carolina Department of Agriculture is located on the Internet at www.ncagr.com/agronomi.

Chris believes the petiole analysis gives him solid information about what the plants in the field or in the greenhouse need. “I really couldn't grow anything in the field or in the greenhouse successfully without taking leaf samples.”

The past several years, he's watched the recommendations made by the petiole analysis. In April, when he sent off leaf samples from his two greenhouses of tomatoes, he had a suspicion that the plants were low in potassium.

“I've watched the fertility requirements for several years and I'm beginning to learn that around this time of the year they're needing more potassium.”

Petiole analysis showed that his diagnosis was right. So, he bumped up the potassium mixture to 13 ounces per gallon of water in the greenhouse. “When the fertilizer is right, it builds a stronger node and makes for a stronger vine.”

Chris is growing tomatoes in the same greenhouses where only two seasons ago he and his father raised their own tobacco transplants. The conversion has been a learning experience for Chris.

For example, he had to learn how to pollinate the tomato flowers. He uses a leaf blower to pollinate the crop.

This season Chris began growing lettuce. He admits he hasn't quite got the fertilizer and soil mixture right on lettuce yet. But he believes following a few adjustments, he'll have as much success with lettuce as he has with tomatoes for the past six years.