August 28, 2014 in Washington Voices

A challenging summer for tomato growers


The tomatoes, the most popular vegetable in the garden, are finally ripe. It’s time to make tomato sauce, stewed tomatoes and BLTs.

Getting tomatoes to this point this year came with some pretty significant challenges. First, the spring weather through June was cool, which kept the soil from warming up enough to give the plants a good start. To overcome this, I had tomato plants under floating row cover until the end of June which held in enough extra heat to triple their size. Then the hot, dry weather kicked in and the challenges really began.

Tomatoes love warm weather but they don’t like day after day of over 90-degree temperatures like we saw in July. As the plants began to bloom in mid-July it was so hot that the bees weren’t flying to pollinate the flowers. They were too busy trying to find water and keeping their hives cool. Secondly, when it gets over 90, pollen tends to dry out and lose its ability to stick to the pistils of the female flower. Hence, no pollination – no fruit. It’s cooled off now so the bees should be working again. If you’d like to help them along take an old electric toothbrush out to the garden and place it on a stem near a flower cluster. The vibration will shake pollen loose and it will float into nearby flowers.

The hot, dry weather also resulted in an increase in blossom end rot and water cracking. Both of these conditions are caused by uneven watering. Blossom end rot is a calcium deficiency caused by changes in water availability to cells and appears as a brown leathery patch on the bottom of the ripening tomato. Water cracking appears as a series of splits and scars around the top of the fruit and is the result of tomatoes getting too much water, which bursts the skin. The cracks usually heal over but the fruit ends up looking rough.

To prevent both these problems, you need to get water deep in the soil and then keep it evenly moist. This usually requires increasing the time and frequency of your automatic sprinkler system to every other day for 20 to 30 minutes. If you don’t have an automatic system, set up a soaker hose with a battery powered timer set to run for 30 to 45 minutes every other day. Once it cools off in September, you can cut back to every two days until we get a frost.

As we get into September, our nights will begin cooling and temperatures will drop below 55 degrees. At this point, tomatoes won’t continue setting fruit. The main challenge then becomes getting the existing fruits ripe before the first frost. You can cover the plants with floating row cover which will hold in as much as 10 degrees of heat both night and day. The fabric lets in water, air and light and is available at garden centers or online.

Pat Munts has gardened in the Spokane Valley for more than 35 years. She can be reached at pat@inlandnw

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