Roanoke Times
                 Copyright (c) 1995, Landmark Communications, Inc.

DATE: THURSDAY, March 9, 1995                   TAG: 9503090050
SECTION: CURRENT                    PAGE: NRV-6   EDITION: NEW RIVER VALLEY 
SOURCE: JOE HUNNINGS
DATELINE:                                 LENGTH: Medium

YOUR GARDEN BENEFITS FROM MANY TOMATO SCIENTISTS' WORK

OK, they don't do it just for the benefit of your personal garden, but they are out there, investigating the ``ins'' and ``outs'' of tomato production.

Although most of these investigators target commercial growers for their studies, many of their results are useful to home gardeners. As an example, research has confirmed the widely held belief that tomato seedlings with no fruit when transplanted will overtake those that have set fruit when transplanted, in terms of development and total yield. This applies to transplants grown in small containers. Seedlings grown in large (i.e., half-gallon) containers may do fine if they fruit before transplanting.

In addition, when you use young transplants with no fruit, pinching back the growing tips of the plants can increase the size of early yields. For this technique to work, plants must be young, with only four or five leaves. Removing the tip forces earlier development of side branches or suckers, which increases the total number of flowers and fruits.

This method sacrifices the very earliest fruits that would have been borne by the flower cluster formed by the pruned-out tip. So you might want to leave a few plants unpruned to get that first tomato of the season as soon as possible. The total yield remains the same. Of course, you can't use this technique if you prune out all suckers.

When you transplant, you also should mulch. This probably isn't news to most gardeners, but study after study confirms the benefits of mulch. Apply clear, white or black plastic mulch to improve early and total yields. Organic mulch also is useful, but a living mulch, such as rye grass, reduces yields.

However, one living mulch that still might be desirable is bush snap beans. Tomato yields are reduced by about a third, but beans produce normally. For those with a small garden, this is a way to get two crops from the same space.

Some gardeners irrigate and prune; some do neither. If you irrigate, you'll be glad to know that one trickle irrigation line per 36 inches of bed width is as good as two, assuming you apply the same total amount of water.

Pruning is not as simple. It turns out the responses of various tomato cultivators on sucker removal differ. For some, light pruning (removing the first four suckers) results in the greatest yield; for others, no pruning gives the highest yield. Experiment with your favorite variety.

On the disease front, researchers have found that high relative humidity can promote blossom-end rot in tomatoes even when other conditions associated with this problem - such as soil fertility and moisture - favor normal growth. If your fruits routinely succumb to this malady, try planting them farther apart to allow better air circulation. This reduces the relative humidity around the plants.

Joe Hunnings is the Virginia Cooperative Extension Service agent for agriculture in the Montgomery County Extension office in Christiansburg. If you have questions, call him at 382-5790.