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Don't let Jack Frost ruin your harvest

For all its beauty, October can be a frustrating month for gardeners. Some years the weather is warm and mild and plants grow beautifully. Other years the frost comes early, and many garden tasks are left undone.

While I can't predict when the weather will change, I can tell you that spending a little time in the vegetable garden right now will let you enjoy the fruits of your harvest for many months to come.

While cleaning up the vegetable patch is always a priority, your first task should be to salvage the last of the produce before it gets too cold or too wet.

"Frost on the pumpkin" might have a poetic ring, but the pumpkins and squash should be harvested before the first cold snap. Since they are warm season crops, they stop growing when temperatures are consistently below 50 degrees. While the fruits tolerate light frost, the frost easily kills the vines. And heavy frost will shorten the storage life.

Harvest winter squash when the "ground spot" changes from white to a cream or gold color. Also check to make sure the squashes and pumpkins you plan to store have hard rinds. Push your thumbnail into the stem and then remove it. If the stem indentation fills with liquid, leave the squash on the vine unless you expect heavy frost. If the indentation is dry, the squash should store well.

Leave the stems on, as those without stems tend to rot quickly. Avoid scratching or bruising them. Do not drop the fruits and do not stack or pile them on top of one another. Damaged produce spoils quickly and destroys other produce in the process.

Once the squash is harvested, cure by placing them in a warm, dry place (80-90 degrees) out of direct sunlight for two weeks. This will set — or suberize — the skins so they are more resistant to decay. This also allows minor scrapes and cuts to heal.

Store winter squashes and pumpkins at 50 degrees in a dry area. Avoid humid areas, such as a root cellar, as they quickly decay under moist conditions. Good air circulation in the storage area is helpful. Never store them in paper or plastic bags, as bags tend to hold in too much moisture.

Under proper storage conditions, acorn squash last about two months; butternut squash last three months; and turban and buttercup squash keep even longer. Check your stored pumpkins and squash every couple of weeks and remove any that turn soft.

Once the squash has been harvested, look at your tomato vines, which are likely covered with large, green tomatoes that will be killed by cold weather. While you might be tempted to wait until the last moment to pluck these fruits, that is a bad idea.

Tomatoes that get wet and cold before they are picked for storage usually crack around the stem ends. When that happens, the fruit quickly starts to spoil.

Mature green tomatoes will ripen off the vine over an extended period. While they will not taste as good as those ripened on the vine, they are better than most of the tomatoes you can purchase during the winter.

Mature green tomatoes are those that have reached the typical size for their variety and are starting to turn light green or white on the bottom. Select only sound, undamaged fruit to store. Even slight openings in the skin allow fungi to grow that will quickly destroy your fruit.

Some green tomatoes that are harvested when conditions are warm and dry will keep until the following spring. Some recommend pulling out the vines and hanging them upside down to let the fruits ripen. I have tried that method and found it cumbersome and messy. Worst of all, the ripening tomatoes fell off the vines and splattered on the floor.

The after-harvest care is critical. Handle the fruits carefully. Spread the tomatoes on flat shallow tray lined with newspaper. Set the fruits far enough apart that they do not touch.

An even better choice is to recycle fruit or tomato crates from you local supermarket. Ask the produce manager to save some of the boxes with their inserts. Then set one tomato per compartment. You can even sort the fruits according to how ripe they are.

Storage conditions are critical. The temperature needs to stay around 50 degrees and the humidity needs to remain dry. High humidity quickly allows the fungi to attack the tomatoes and destroy them.

Watch the fruits in storage and remove those that are starting to ripen. Let them finish ripening on a table or countertop at room temperature. Tomatoes do not need sunlight to ripen, so never place them on the windowsill to turn red.


Larry A. Sagers is the Utah State University Extension horticulturist at Thanksgiving Point.