10 Crops To Harvest Before The First Frost

The National Weather Service has issued a frost warning!

It’s a last-minute scurry. A clear, calm night and a frost warning. While many vegetables like carrots, kale, and parsnips don’t mind a little frost and may even taste better, quite a few of our garden favorites are killed by the frost, and their fruits can also be damaged. 

While not every vegetable needs to be gathered before the first freezing temps, many, like tomatoes, can be rendered mushy and damaged by even a short time below freezing. A few minutes won’t ruin them, but if you have frost in the forecast, grab a basket or two and get the tender veggies inside. 

Most plants in the Solanaceae family, like tomatoes, eggplants, and peppers, will not survive a frost. At or below freezing, it doesn’t take long for these soft fruits to go bad. Summer vegetables like tomatoes and cucumbers have a high water content. When the water in their cells starts to freeze, it expands, rupturing the cell walls. After thawing in the morning sun, the cell walls collapse, unable to provide the structural support they did when intact. The vegetable gets mushy and loses its appeal. Grab a basket, snips, and head out the evening before for some last-minute harvesting.

The first overnight frost of the year is often followed by several more weeks of warm weather. A light frost–usually the first frost of the year–may last only a few hours in the early morning before dawn but is still enough to kill many of our favorite garden vegetables and flowers. If you’re growing plants in containers, they can be brought indoors overnight and set out in the morning. Setting them in an unheated garage or shed is often enough protection for a quick frost. 

Plants in the garden can be covered with frost cloth or even an old bed sheet. Ensure the covering goes all the way to the ground and is anchored so it won’t allow drafts or blow away in the wind. Frost cloth (or old bedsheets) works by trapping radiant heat from the ground, keeping it around the plant. They can protect sensitive plants from temperatures several degrees below freezing for short periods if properly used. Remove the covers in the morning. 

Tomatoes

The last tomato harvest of the fall causes a commotion in my garden. Any tomato that has started to turn even a bit of color gets grabbed for future ripening in the house. Even green tomatoes can be picked, and there are many recipes online for creative ways to use them. A light frost will kill most tomato plants, and you’ll see any fruits you missed hanging under the now shriveled leaves. If you check them and they’re firm and unblemished, grab those too. 

Any tomatoes you missed that fell on the ground and froze are best picked up that first morning and tossed in the compost. After a day or two, they get mushy. If you leave them in the garden, you may have more volunteer tomatoes than you bargained for in late spring. They can come up like weeds.

Sweet Peppers

Pepper plants love their heat, and even a quick frost can be their doom. A few hours at or below freezing is enough to turn red, orange, yellow, and green sweet peppers into unappealing soft lumps. Snag all the peppers that have reached mature size, even if they aren’t quite ripe yet. Bring them into the house and ripen them in a paper bag or a bowl on the counter. 

Cucumbers

These delectable veggies are mostly water, so you can imagine what a frost does to them. Cucumbers are easily damaged by freezing, and the vines will be kaput in the morning anyway. Overlarge cukes can be tossed in the compost pile, and eating-size cukes can be preserved or turned into a batch of refrigerator pickles. 

Hot Peppers

Just like sweet peppers, a little frost will spell the end of the line for hot peppers. While a quick frost won’t hurt the fruits hanging on the plant, it’s a good idea to harvest them anyway. An extra degree or two can make the difference between crispy, ripe habaneros and soggy mush.

Sweet corn?

Your sweet corn is probably done producing, and you’ve cut the stalks for fall decorations. But, if you succession planted sweet corn, go ahead and pull the last ears before the frost. They won’t keep developing, and you’ll capture more of the sugars before they start turning to starch. 

Eggplant

From the same family as tomatoes, eggplants are also a heat-loving vegetable. Although the skin can seem tough, especially if they’ve been on the vine a bit too long, it won’t take more than a few hours of frosty temps to render eggplants inedible. 

Summer Squashes

Like many other squashes, a night of frost will render a bushy zucchini plant brown and deflated. Winter squashes like butternut or acorn squash will be fine left out, even if the vines die back. They just need to be gathered before a hard freeze damages them. But tender-skinned summer squashes like zucchini or pattypan squash should be brought indoors.

Green beans

Green beans are not tolerant of frost, and if you’ve still got a few pods hanging on your bushes or vines, grab them and toss them in the basket before freezing temps. If you’ve been staying on top of harvesting them, it won’t be much work to grab the last few. Other types of beans meant for drying, like black beans or Jacob’s Cattle Bean, are perfectly okay to leave for a while after the frosts. For those types, you’re looking for the pod to dry and the beans inside to be hard, which often won’t happen until later in autumn.

Okra

Okra is another tropical species, and while it may survive a light frost, there’s no reason not to snag all the pods you can beforehand. Since okra plants will keep producing until the frost, you’ll likely have a few pods out there at optimum size, and a few younguns. Snag them all if you are certain the evening low will result in a killing frost. If the frost warning is for a glancing blow, leave the immature pods in case the plant survives. 

Basil

If you’ve been succession planting basil and still have some young basil plants producing leaves, bring them inside or harvest what you can. Basil, left out through a frost, will turn black and slimy after only a light freeze. Many herbs like rosemary, sage, and thyme will be alright with a light frost, but basil isn’t one of them. If you’re in a hurry, nip entire stems and sort them out later. 

Vegetables aren’t the only thing to grab for a last-of-the-year harvest before the frost. Many annual flowers and tender perennials we grow as annuals won’t tolerate a frost. If you’ve got a flower patch, cut a big bouquet or two of all the ready-for-harvest zinnias, dahlias, cosmos, marigolds, and phlox. Bring in begonias, hostas, impatiens, and petunias. Don’t forget to take a few quick cuttings if you’d like to preserve your coleus for next year.