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  • Writer's pictureKassi Kuppinger

Harvesting Your Cool Crops Before the First Frost

As the weather begins to cool down and nighttime lows begin to dip, we are all being reminded that the warm weather is making its way out, and cooler weather is moving in! Fall will officially be here in just a couple of weeks, which means you may have to start keeping a closer eye on the weather to make sure you harvest your cool-season crops before the first frost.

chard plants - Cool Crops Before the First Frost

What are Cool Season Crops?

Cool-season crops are garden vegetables that generally grow better in cooler weather. That being said, cool crops grow best early in the growing season (mid-late March) or late in the growing season (early August). Most cool crops need around 40-70 days to reach maturity, at which time they will be ready to harvest! Sometimes this timeframe comes very close to the average first frost date here in Northern Colorado. The average first frost date here in Colorado generally lands close to the beginning/middle of October, so this is generally a good time to start harvesting some of your cool crops. Some of them will be more sensitive to frost, while some cool crops are hardier and can tolerate a light freeze.

Best Cool-Crops to Plant in Colorado

Many cool crops that are commonly seen in fall gardens throughout northern Colorado include the following:

a bunch of radishes
  • Beets

  • Broccoli

  • Brussels sprouts

  • Chives

  • Cabbage

  • Carrots

  • Cauliflower

  • Swiss chard

  • Kale

  • Leeks

  • Lettuce

  • Onions

  • Parsnips

  • Peas

  • Radishes

  • Spinach

  • Turnips

While this list is not exhaustive, these are the types of cool-season crops that are most often planted in gardens either in the early spring or late summer. When planting later in the season, it is important to take into consideration the number of days till harvest. If you are trying to grow your cool-season crops from seed, check the back of your seed packets. Since the window for growing cool-season crops at the end of the summer is rather short, some crops may need to be started indoors, or you may want to pick up some garden starts from your local garden center. If a crop requires 70 days to reach maturity, that would require planting near the middle/end of July, which is often still far too hot for the cool crops to be able to germinate. Vegetables with longer maturation periods include things such as broccoli, Brussels sprouts, cabbage, onions, cauliflower, and celery. Consider starting these from seed indoors or buy some garden starts! Crops that have shorter maturation periods and can be grown from seed include kale, peas, radishes, spinach, turnips, beets, carrots, potatoes, lettuce, and other leafy greens.

Which Cool Season Crops are More Tolerant of the Cold?

Some of these vegetables are more cold-hardy than others, meaning that some will be able to withstand cold temperatures and even frost better than others. Cold hardy vegetables include broccoli, Brussels sprouts, cabbage, collards, onions, rutabaga, kale, kohlrabi, peas, radishes, spinach, and turnips. These vegetables can withstand cold temperatures as well as frost, though it is still recommended to harvest before or soon after the first frost, as the health and integrity of the plants will diminish as the season progresses into colder weather. Other cool-season crops that are semi-hardy include cauliflower, celery, beets, carrots, potatoes, arugula, lettuce, and other leafy greens. Due to the more tender nature of these plants, they can tolerate cooler temperatures but often will not handle frost well. Harvest these plants as soon as nighttime temperatures really begin to dip into the low 40’s for best results.

cool crops at a farmers market

What If You Don't Harvest Your Cool Crops Before the First Frost?

As we said above, some cool-season crops are more cold tolerant than others. So, keeping that in mind, many of your cool crops will become undesirable if left unharvested in temperatures that are beyond what they are capable of handling. In many cases, this leaves you with frostbitten, wilted, soggy, or mushy plants. When the tender greens or meat of the vegetables comes in direct contact with frost or ice, this destroys the vegetable and makes it very undesirable to consume. You can always try to stretch out the growing season by putting frost cloth or some other sort of shelter over your garden to keep the frost from coming into direct contact with your vegetables, but this will only help for so long as the temperatures tend to dip quickly here in Colorado.


If you have any questions about cool crops or anything pertaining to your fall garden, please let us know! We are just as eager as you are to stretch the growing season as long as possible and are here to help with whatever you need. We can be reached via phone or email, and you are always welcome to stop by Bath Garden Center to speak to us in person!


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