As the days grow shorter and autumn settles in, it's time to make the last harvest of the season. This last harvest isn’t just a farewell—it’s a chance to gather what remains. Knowing how to properly harvest each crop ensures peak flavor, longer storage, and a satisfying close to your vegetable garden for yet another year..
As the first frost approaches, the harvest of warm-season vegetables like tomatoes, peppers, and squash is imminent. For other cool-season crops, like Brussels sprouts, spinach, and beets, you can continue to harvest even after frost.
Here is your guide to collecting the last of your produce from the vegetable garden at the end of the growing season.
What to Harvest Before the First Frost | What Can Be Harvested After the First Frost | More Information
Beets | Broccoli | Brussels Sprouts | Cabbage | Cantaloupe | Carrots | Cauliflower | Cucumbers | Dry Beans | Eggplant | Greens | Green Beans | Green Onions | Horseradish | Kale | Kohlrabi | Leeks | Lettuce | Melons | Okra | Ornamental Corn | Parsnips | Peas | Peppers | Popcorn | Pumpkin | Radish | Rutabaga | Salsify | Spinich | Summer Squash | Sweet Potato | Swiss Chard | Tomatoes | Turnips | Watermelon | Winter Squash
What to Harvest Before the First Frost
Warm-season vegetables will be killed by the first frost of the fall. This means produce needs to be collected before the temperatures dip below freezing.
Climacteric vs. Non-Climacteric
Some vegetables, like tomatoes and cantaloupe, can be harvested immature and ripened off the plant. These species are referred to as climacteric. They produce abundant ethylene even after harvest. Ethylene is the plant hormone responsible for ripening. Other species, such as squash, watermelon, and eggplant, are non-climacteric. These vegetables will not continue to ripen after harvest. They may become softer (decay), but they will not continue to develop and change (ripen).
This is important to understand, as climacteric fruit and vegetables that must be harvested before frost (warm-season vegetables) can be harvested immature and ripened. Non-climacteric fruits must be consumed immature (like peppers, green beans, and summer squash) or harvested fully ripe. This means that if they are not fully ripe before the first frost and they are not consumed immature, then they will be lost to freezing temperatures.
Tomatoes
When frost is imminent, mature green tomatoes can be harvested and ripened indoors. Just before the first frost, remove all mature, greenish-white fruit from the vines. They should be solid, firm, and free of defects. Remove the stems, then clean and dry the fruit.
Individually wrap each tomato in a piece of newspaper. Store wrapped tomatoes in a cool (60 to 65°F), dark location, such as a basement or cellar. The wrapped fruit can be placed in a single layer in a box or on a table.
Inspect the tomatoes frequently and discard any damaged or decaying fruit. When the tomatoes begin to color, remove the newspaper and place them at room temperature.
Learn more in this article: Growing Tomatoes in the Home Garden.
Peppers
Peppers will not continue to ripen once harvested, although some types may still change from green to their characteristic color of yellow, red, or orange. However, peppers can be enjoyed immature. A green pepper is simply a colored pepper that has yet to change color.
Harvest all fruit before the first frost.
Learn more in this article: Growing Peppers in the Home Garden.
Eggplant
Eggplant will not mature after harvest. Any fruit that are at the proper stage of maturity (2 to 6 inches in diamter, shiny and firm) should be harvested before the first frost. Overmature fruit (soft, dull, seedy, and tough) and those that are too small can be discarded.
Learn more in this article: Growing Eggplant in the Home Garden.
Summer Squash
The summer squash, such as zucchini and patty pan, in many home gardens has already succumbed to disease or insect issues by the end of the growing season. If plants are still producing, all fruit needs to be harvested before the first frost. Squash will not continue to ripen after harvest, but summer squash is consumed immature, so harvest any fruit that is large enough to eat.
Learn more in this article: Growing Squash in Iowa.
Winter Squash, including Pumpkins
Winter squash, including pumpkins, can be harvested at either a mature or immature stage, but only the fruit that has fully matured and cured will store well. Harvest any fruit of usable size before the first frost. Squash does not ripen after harvest, so any immature fruit (those that can be easily punctured with your thumbnail) should be used first.
Learn more in this article: Growing Squash in Iowa.
Cucumbers
Much like summer squash, cucumbers are harvested when they are of an appropriate size and not allowed to fully mature, as they get too seedy and tough. Cucumbers do not ripen after harvest, but they are consumed while still immature. Harvest any fruit of appropriate size before the first frost.
Learn more in this article: Growing Cucumbers in the Home Garden.
Melons
Whether a melon will ripen off the vine or not (climacteric vs. non-climacteric) is not always very clear. Generally, melons are non-climacteric, but this can vary depending on the species and variety. Overall, all melons need to be harvested before the first frost. Those varieties that will not ripen after harvest will be lost. The few that will ripen after harvest can be ripened indoors.
Watermelon
Watermelon will not ripen after harvest, so they should be harvested before the first frost when they show the characteristic signs of maturity, such as a yellow ground spot or a brown "pigtail" (tendril). Those melons that are not fully ripe before the frost will be lost. Learn more in this article: Growing Watermelon in the Home Garden.
Cantaloupe
Hundreds of cultivars of cantaloupes and cantaloupe-like melons are available in the subspecies Cucumis melo subsp. melo. The two major varieties grown in Iowa include var. cantalupensis and var. reticulatus. Cantaloupes and cantaloupe-like melons have netted rinds (but not always) and can be lobed or smooth. These melons can be either climacteric or non-climacteric, meaning some cultivars will ripen after harvest, and some will not.
Those cultivars that are harvested at "full slip" when the stem readily detaches from the fruit will, in general, continue to ripen after harvest. They need to be harvested before the first frost, and those that are near-ripe can be harvested before full slip and allowed to fully ripen indoors on the counter. Learn more in this article: Growing Cantaloupe, Muskmelon, and Other Melons in the Home Garden.
Honeydew
Honeydew melons will not slip or readily detach from the fruit when fully ripe. These melons and others that belong to the variety Cucumis melo subsp. Melo var. indorus will, in general, not ripen after harvest, but there are some exceptions. Honeydew melons must be harvested before the first frost, and those that are not fully ripe may or may not ripen (most will not). Those melons that do not exhibit signs of maturity, such as a softening of the blossom end and a pleasant aroma, can be attempted to ripen indoors, knowing they may never fully develop their characteristic sweetness and flavor. Learn more in this article: Growing Cantaloupe, Muskmelon, and Other Melons in the Home Garden.
Other Melons
Hundreds of unique melons from China, the Philippines, Japan, Northern Africa, and Central Asia can be grown in the home garden. In general, these melons will not ripen off the vine, but some species/varieties may. Those that are harvested at "full-slip" are more likely to continue ripening after harvest, but this is not universal. These melons must be harvested before the first frost, and can be treated much like honeydew melons. Those that do not exhibit their typical signs of maturity can be attempted to ripen indoors after harvest, knowing they will likely not develop their characteristic flavor and sweetness.
Ornamental Corn and Popcorn
Both ornamental corn and popcorn will typically dry and mature before the first frost. Both types of corn benefit from being allowed to dry for as long as possible on the stalk before harvest, and kernels will continue to dry after the first frost. Harvest when the kernels are hard and the husks, shank, and stalk are completely dry.
Learn more in these articles: Growing and Harvesting Ornamental Corn and Growing and Harvesting Popcorn in the Home Garden.
Green Beans
Green beans (also known as snap beans, string beans, or wax beans) are sensitive to frost. Green beans will not continue to ripen after harvest, but they are consumed immature. Therefore, harvest any pods that are large enough to eat before the first frost.
Learn more in this article: Growing Green Beans.
Dry Beans
Dry beans require more time to harvest, as the pods need to dry completely before they are harvested. When the pods are dry and rattle a little when shaken, the bean seeds inside are mature and ready to harvest. Plants will be killed by frost, but beans will continue to dry after the first frost, so it is often beneficial to leave pods on the plant as long as possible, but before they split open, so they can fully dry.
Learn more in this article: All About Beans.
Okra
Okra will continue to produce until killed by the first frost. Okra does not continue to ripen after harvest, but the pods/fruit are consumed immature. Therefore, harvest any pods that are large enough to eat before the first frost.
Learn more in this article: Growing Okra in the Home Garden.
Sweet Potato
Sweet potatoes have a long growing period, and maturity is only reached by growing them in the garden for as long as possible. Plants are not frost-tolerant, and the tubers should never freeze. However, harvest can wait until just after the first frost of the season, as the vines will die back, but the soil will remain above freezing. This gives the plant the most time to reach maturity without sacrificing the quality of the crop.
Learn more in this article: Growing Sweet Potatoes in Iowa.
What Can Be Harvested After the First Frost
Cool-season vegetables tolerate light frost, and some may even develop better flavor if allowed to experience a few nights below freezing.
Leafy Greens
Nearly all leaf green species can be harvested well into the fall. This includes lettuce, spinach, kale, chard, and endive, as well as beet, mustard, turnip, and collard greens. They tolerate light freezes well, and as long as plants are green and healthy, they can be harvested. Do not harvest leaves when leaves are frozen. Leaves harvested while they are below freezing will become limp once they fully thaw. However, if leaves are allowed to naturally thaw and rehydrate on their own (usually by mid-morning on those crisp autumn days), they will be of good quality.
Learn more in this article: Growing Leafy Greens in Iowa.
Root Crops
Nearly all root crops, including carrots, beets, turnips, rutabagas, radishes, and parsnips, can be harvested after the first frost. For some root vegetables, including parsnips and rutabagas, exposure to several nights of temperatures below freezing helps produce sweeter, more flavorful produce.
Root crops will not continue to mature after harvest so harvest them when they reach the optimal size. The ideal size for root crops grown in Iowa are shown below:
- Beets | 1.5 to 3 inches in diameter
- Carrots | ¾ inch or more in diameter
- Parsnips | 10 to 12 inches long, leave in the ground as long as possible
- Radish | ~1 inch in diameter
- Radish, Diakon/Winter | 1 to 2 inches across, 8+ inches long
- Rutabagas | 4 to 5 inches in diameter
- Turnips | 2 to 3 inches in diameter
Learn more in these articles:
- Growing Beets in the Home Garden
- Growing Carrots and Parsnips
- Growing Radishes in Iowa
- Growing Turnips and Rutabagas in the Home Garden
Cole Crops
Cole crops include Brussels sprouts, kohlrabi, broccoli, cauliflower, and cabbage. In Iowa, these cool-season crops have longer growing seasons than other cool-season crops, such as leafy greens and root crops. Crops of cabbage, cauliflower, broccoli, and kohlrabi planted in mid-June to mid-July will be ready for harvest by late September or early October. These crops tolerate light freezes well and should only be harvested when they have reached the optimal stage of maturity. This may or may not be after a freeze.
Brussels sprouts take longer to reach maturity and benefit from being exposed to below-freezing temperatures, as it often improves flavor.
Learn more in this article: Growing Cole Crops in the Home Garden.
Peas
Many Iowa gardeners grow peas as a spring crop. However, a late-season harvest can be made when a new crop is planted in mid to late August. Peas are harvested before they are fully mature. Garden peas are best picked just as the pods swell and round out, but before they make a hard, bumpy outline in the pod. Harvest snow and snap peas (edible pod peas) just as the seeds begin to form, but while the pod is still flat.
Peas do not continue to mature after harvest, but they do tolerate light freezes well. Harvest when they are the appropriate size, whether that is before or after the first frost.
Learn more in this article: Growing Peas in Iowa.
Green Onions, Leeks, and Scallions
Green onions (or scallions) are often planted as a spring crop in Iowa. However, a fall crop can be planted in late summer for harvest in fall, about 4 to 6 weeks later. Green onions tolerate frost and are harvested immature. This requires them to be harvested when they reach a usable size, whether that is before or after the first frost.
The harvest of leeks can be extended well past the first frost date by mounding several inches of straw around the base of plants to prevent the ground from freezing. This allows for harvest until the ground freezes.
Learn more in these articles: All About Onions and The Other Onions.
Salsify
Harvest salsify in November after several light freezes. The cool fall temperatures enhance the oyster-like flavor of the roots. After harvest, trim off the foliage ½ inch above the roots and store the salsify at a temperature of 32°F and a relative humidity of 95-98%.
Salsify can also be left in the garden over winter and harvested in early spring before growth resumes.
Horseradish
The best crop of horseradish is harvested in late October or November. Carefully dig the horseradish and cut off the foliage about 1 inch above the crown. Store horseradish in a refrigerator or root cellar at a temperature of 32 to 40°F and a relative humidity of 90 to 95%. When storing horseradish, keep the roots out of light. Light will turn the roots green.
Gardeners can also leave some horseradish in the ground over winter. Harvest the remaining crop in early spring before growth resumes.
More Information
- Frost and Freeze Dates in Iowa
- Vegetable Growing Guides
- Vegetable Harvest Guide
- Planting and Harvesting Times for Garden Vegetables (PDF)
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