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The Spokesman-Review Newspaper
Spokane, Washington  Est. May 19, 1883

Shock therapy

Tricks force tomatoes to ripen before first frost

Two weeks ago, I wrote that it’s time to start pruning your tomato plants to force them to ripen the existing fruit. While several gardeners have told me their tomato plants are putting out a lot of ripe tomatoes, it appears most gardeners are frustrated that this is a lousy year for growing them.

Our cool, wet spring got everything off to a slow start. Most plants are about three weeks behind in their development. My own tomato plants have a lot of green tomatoes on them but they just don’t seem to be in the mood to ripen them.

Knowing there are many gardeners out there in the same predicament, I dedicate today’s column to a discussion of how to shock your tomato plants so they will give you something to harvest and enjoy.

Before we begin, I wanted to remind everyone that our first frost is probably only two to four weeks away – a sobering thought, to be sure, but this underscores the importance of making the most of our last few weeks.

Nothing tastes more delicious than a fully ripe, homegrown tomato. That’s why I always start pruning back my tomato plants in August. This means trimming most of the branches back to the first stem that has tomatoes growing on it. I also remove any undersized tomatoes that don’t even remotely have a chance of ripening before frost. Then I remove the lowest leafy branches – not branches with tomatoes on them – to improve air circulation and assist with ripening. It’s actually the warmth of the sun and not the light that causes tomatoes to ripen.

Some years, doing all of this isn’t enough. There are two rather drastic steps you can take – cut back on water or slice through some of the plant’s roots.

Throughout the season, we’ve been watering our gardens regularly. Withholding water from the tomato plants will shock them and cause them to ripen the fruits. When a plant is drought-stressed like this, it won’t put out new foliage or blossoms.

To cut through a plant’s roots, place a shovel about 6 to 12 inches from the main stem and cut a few inches down into the soil in a half-circle around the plant. Don’t cut all the way around it. The plants will continue to grow but the shock of having severed roots will force them to ripen their fruit.

Over the next few weeks, it’s important to monitor the weather forecasts so you know when frost is expected. Tomato plants can survive light frosts, but if a heavy frost is predicted, you have a few options. You can cover the plants with blankets at night to keep the frost off them. You can also pick full-sized, green tomatoes and take them to a dark location like a basement. Set the tomatoes in a single layer on sheets of newspaper and cover them with more newspaper. Or you can pull up the entire tomato plant and hang it in a dark area where the tomatoes will continue to ripen. Be sure to place a tarp underneath it in case fruit drop off the plants. You will be amazed at how well the tomatoes ripen using either of these two methods.

If you still end up with some green tomatoes, don’t despair. You can always make fried green tomatoes or green tomato pie which, believe it or not, tastes like an apple pie.

Susan Mulvihill can be reached via e-mail at inthegarden@live.com.