One sunny August afternoon, I walked into our “Tomato” greenhouse only to find my husband, Frank, yielding a machete (OK, a large knife) chopping off the tops of all the tomato plants.

Positive that the heat finally got to him and he’s gone berserk, I yelled: “What the heck are you doing?”

The long rows of tomato plants — so painstakingly planted and tied up and with the tips sprouting with tons of yellow blossoms — had looked tantalizing as with every yellow blossom I see not the blossom but a red, luscious tomato.

And now, before my eyes, the top of every tomato was chopped off.

After a little more ranting, raving, expletives and what not, I finally calmed down long enough to listen to his explanation.

It seems that with the larger tomato plants such as Beefsteak, Ultra Girl, Early Girl, etc, any new flower forming will not have the time it needs to grow into a large tomato before the coming frost, even if that frost is two or three weeks away.

By trimming off the top of the plants around the 15 to 20th of August, all the plants’ energy will go into the growth of the tomatoes that are already on the vine.

Traditionally, we can get a frost by the end of August/beginning of September, especially in the outlying areas of Whitehorse and the communities.

Oftentimes, if we can survive this first freeze by heating the greenhouse, we can usually buy enough time to vine ripen the rest of the tomatoes.

Depending on how sheltered or the location your greenhouse, an unheated greenhouse can withstand about minus 3 to 4°C.

Pruning the top of the tomatoes is not done to the cherry or smaller type of tomatoes until about two weeks before shutting down the greenhouse. The timing of this event depends a lot on the weather and your personal time schedule.

It seems by the time the kids go back to school, gardening takes a back seat and other interests prevail.

We have never pruned other plants such as cucumbers or peppers as the ripening process is much faster than tomatoes.

The trimming of the tops of tomato plants is still a bittersweet moment as it signals the beginning of the end of gardening season.

I still have a hard time ruthlessly chopping off the tops of the plants and will use any excuse to hold off doing this chore for another day. However, I do realize by prolonging the needed pruning, I am trading a potentially vine ripened red tomato for a window-sill ripened one.

Ingrid Wilcox operates Lubbock Garden and Floral Consultant and offers gardening, greenhouse and flower arranging workshops. Contact her at ingrid@northwestel.net.

PHOTO: iStockphoto