Planting a Fall Vegetable Garden

Plant a fall and winter harvest vegetable garden in mid-to-late summer.

Hardy, cool-weather crops are best suited for the fall and winter vegetable garden. Cool-weather vegetables like to get their start in warm soil and come to maturity when days and nights are cool.

Cool-weather vegetables include leafy crops and root crops: beets, carrots, and parsnips; salad greens, including lettuces; and members of the cabbage family like red and green cabbage, kale, collards, broccoli, cauliflower, and Brussels sprouts. These crops are considered hardy because they can tolerate a light frost and can even survive when temperatures dip down to the mid-20s. (The flavor of many cool-weather crops is enhanced when the plants are touched by frost.)

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The fall-harvest vegetable garden also can include tender, warm-season crops, but these crops must come to harvest before the first frost. Warm-weather crops include tomatoes, cucumbers, okra, squashes, melons, pumpkins, peppers, eggplants, and beans. These must be planted in early summer for a fall harvest; these crops must be harvested before the first fall frost.

Growing season and vegetable garden planting tips

The time for planting vegetable garden crops depends upon where you live. The number of days between the last frost in spring and the first frost in autumn is the length of your growing season. Every crop you plant must germinate, grow and come to harvest during your growing season. If your growing season is too short for the crops you want to grow, you must assist nature by extending the growing season with crop coverings or protectors.

Cool-season vegetables are best suited for the beginning and end of the growing season, for planting in spring, autumn, and winter. These plants grow best as the soil and air temperatures become warmer in spring and as the heat wanes in late summer and autumn. Cool-season vegetables thrive when the temperature highs are in the range of 70º to 75ºF (21-24ºC). (Cool-season crops usually require a minimum germination temperature of 40º to 50ºF.)

Hardy cool-season vegetables are the best selection for planting in the early spring for late harvest and in late summer for fall and winter harvest. Hardy crops can be sown directly in the garden as early as 2 or 3 weeks before the last frost in spring. These same crops will grow into the cool of autumn when planted in late summer; they can withstand the first fall frost.

Planting the fall and winter vegetable garden may require a bit more planning than planting the spring garden. Crops for autumn and winter harvest that are not grown under cover must be planted early enough that they come to harvest before the first freeze in autumn, but not so early that the heat of summer reduces their output. In spring, the garden is nearly a blank slate with plenty of room for planting. In late summer and early fall when the autumn and winter garden is planted, space in the garden may be limited–many late summer harvest plants are still in place.

Crops for fall and winter harvest require enough heat to grow and reach maturity, but not so much that they are scorched or grow too fast, set seed, and wither too soon. Cool-season crops are the best choice for planting in late summer and early fall, just as they are suited for growing in spring.

A cool-season crop planted in autumn can take as much as three weeks longer to come to harvest than the same crop planted in spring. That’s because the days are growing shorter and less warm as autumn turns to winter.

Cool-season vegetables for fall harvest

Crops for autumn and early winter harvest are cool-season crops—crops that like to get their start in warm soil and air but yield best when they come to harvest when temperatures are cool.

Cool-season crops can be planted twice a year, first in early spring for harvest before the summer heat arrives and again in mid- to late summer and autumn for harvest in the cool of autumn. Some people call the autumn harvest of cool weather crops “the second season.”

Crops that can withstand a light frost—the first frost in autumn–are broccoli, Brussels sprouts, cabbage, carrots, chards, collards, radishes, and spinach. Crops that can withstand a heavy frost—usually the second or third frost in autumn or early winter are beets, cauliflower, endive, kohlrabi, lettuce, and peas.

Cool-season vegetable guide

As a quick guide, here’s how many days several cool-season crops need to reach maturity:

• Crops that require 90 days: beets, Brussels sprouts, cabbage, carrots, cauliflower, globe onions, parsnip, and rutabaga.
• Crops that require 60 days: broccoli, early cabbage, early carrots, winter cauliflower, chard, collards, kohlrabi, leeks, and turnips.
• Crops that require 30 days: chives, leaf lettuce, mustard, bunching onions, radishes, and spinach.

Plan the fall and winter vegetable garden step-by-step

Cool-season crops are best suited for planting in autumn, winter, and spring. In spring, cool-season crops can be planted just before or just after the last frost. Planting cool-season crops in autumn and winter takes a bit more planning.

To plan and plant your autumn and winter garden follow these steps:

Step 1. Start with the number of days it takes the crop you are planting to grow to maturity and harvest. Days to maturity will be listed on the seed package. (If you are transplanting vegetable seedlings from the garden center, the days to maturity from transplanting are usually listed on the plant marker.)

Step 2. Determine the average first frost date in your region. If you are not sure, check with a nearby garden center, the master gardener program in your area, or the county or state agriculture extension office. Remember that this date is an average and thus a guideline for your calculations. The first frost date varies from year to year.

Step 3. Add 10 days to the number of days to maturity for the crop you are planting. Now count back on a calendar from the average first frost date the total number of days for each crop. That is the last recommended date to direct seed the crop. (Direct seed means sowing the seed in the soil of your garden.)

Prepare to plant the fall vegetable garden

• Know the average date of the first frost in autumn. (You can get this information from a local garden center or cooperative extension.) Check the days to maturity on seed packets and count back that number from the first average frost date to determine the last day that the seeds can be planted and still produce a crop. Add a week to ten days just to be safe.

• Choose cool-season crops for the second-season garden. Cool-weather crops germinate best and thrive as young plants in warm soil and warm temperatures. Cool-weather crops mature best when day and night temperatures average no greater than the low 60s and mid to high 50s. (These are exactly the temperatures that cause warm-weather, tender crops to falter.)

• If you do plant tender crops in late summer, plant varieties that will mature and be ready for harvest in 50 days or less.

• Have at the ready crop protectors: (1) floating row covers such as lightweight Remay fabric that can be draped across crops if temperatures turn cool or cold unexpectedly. Anchor floating row covers in place with stones or garden staples; (2) Hoops made from wire or irrigation tubing over which you can drape clear plastic sheeting to create a plastic tunnel or mini-greenhouse; you can also use two-by-four or four-by-four inch mesh wire fencing to create a half tunnel over which you can drape clear plastic sheeting; (3) A thick layer of straw, dried leaves, or other organic mulch can be forked around crops to keep the soil warm.

When to plant each fall-harvest vegetable

Here’s a crop-by-crop guide for the number of days from sowing to harvest for the most popular autumn harvest crops: (these numbers may vary slightly by variety):

• Beets: count back 74 days: 5 days to germination + 55 days to maturity + 14 days factoring for short days. Direct sow beets in the garden. Beets can survive a heavy frost.
• Broccoli: count back 95 days: 5 days to germination + 21 days to transplant size +55 days to maturity + 14 days factoring for short days. Start broccoli indoors then transplant to the garden. Broccoli can withstand light but not heavy frost without protection.
• Brussels sprouts: count back 120 days: 5 days to germination + 21 days to transplant size + 80 days to maturity + 14 days factoring for short days. Start Brussels sprouts indoors then transplant to the garden. Brussels sprouts can withstand light but not heavy frost without protection.
• Cabbage: count back 99 days: 4 days to germination + 21 days to transplant size + 60 days to maturity + 14 days factoring for short days. Start cabbage indoors then transplant to the garden. Cabbage can withstand light but not heavy frost without protection.
• Carrots: count back 85 days: 6 days to germination + 65 days to maturity + 14 days factoring for short days. Direct sow carrots. Carrots can withstand light but not heavy frost without protection.
• Cauliflower: count back 90 days: 5 days to germination + 21 days to transplant size + 50 days to maturity + 14 days factoring for short days. Start cauliflower indoors then transplant to the garden. Cauliflower can survive heavy frost.
• Chard: count back 69 days: 6 days to germination + 50 days to maturity +14 days factoring for short days. Direct seed chard. Chard can survive heavy frost.
• Collards: count back 94 days: 4 days to germination + 21 days to transplant size + 55 days to maturity + 14 days factoring for short days. Start collard seed indoors. Collards can withstand a light frost but not heavy frost without protection.
• Endive: count back 142 days: 12 days to germination + 21 days to transplant size + 95 days to maturity+ 14 days factoring for short days. Start endive seed indoors. Endive can survive heavy frost but does best with some protection.
• Kohlrabi: count back 86 days; 7 days to germination + 65 days: days to maturity + 14 days factoring for short days. Direct seed kohlrabi. Kohlrabi can survive heavy frost.
• Lettuce, leaf: count back 76 days: 3 days to germination + 14 days to reach transplant size + 45 to maturity + 14 days factoring for short days. Start lettuce indoors for best results then transplant to the garden. Lettuce can survive a light frost but not heavy frost without protection.
• Peas: days: count back 70 days: 6 days to germination + 50 to maturity+ 14 days factoring for short days. Direct seed peas. Peas can survive heavy frost.
• Radishes: count back 42 days: 3 days to germination + 25 days to maturity + 14 days factoring for short days. Direct seed radishes. Radishes can withstand light frost but should be protected from heavy frost.
• Spinach: count back 64 days: 5 days to germination + 45 days to maturity+ 14 days factoring for short days. Direct seed spinach. Spinach can withstand light but should be protected from heavy frost.

Tips for planting fall harvest vegetables

• Know your area’s average date of the first autumn or winter frost. You can get this date from a nearby garden center or nursery or from the local cooperative extension. Remember the average date is an average, frost may arrive sooner or later this year.
• Always choose the fastest-maturing varieties of a crop for fall harvest.
• The optimal number of days to harvest will be printed on the seed packet or in the grower’s seed catalog. This number assumes long days and warm temperatures.
• The optimal soil temperature for seed starting is 80°F (26°C).
• Crops always take longer to mature in the late summer and fall because the number of hours of sunlight is decreasing along with air and soil temperatures–so factor in 10 to 14 additional days for plants to mature as daylight hours grow shorter.
• Cabbage-family crops are commonly seed-started indoors and then transplanted into the garden when they reach about 4 inches (10cm) tall. Cabbage-family crops include cabbage, cauliflower, broccoli, Brussels sprouts, and collards.
• As frost approaches, remove mulches from around plants; this will allow the soil to absorb radiant solar heat that can be released back into the garden at night.
• Protect frost-sensitive crops by covering them with a horticultural blanket when frost is near.
• Autumn crops can easily be grown on or after the first heavy frost or during freezing weather, but they must be covered and protected. Place a simple plastic tunnel over the crop.

Protecting fall and winter harvest crops–extending the season

To enjoy cool-season vegetables past the first frost in autumn and even to enjoy many fresh-picked vegetables all winter, you will need to extend the growing season. Extending the growing season in autumn (and in early spring before the last frost) requires protecting or covering your crops so that they are not harmed by sudden changes in temperature or freezing weather.

Growing autumn and winter cool-season crops in a cold frame or covering them with a cloche or plastic tunnel will protect them from freezing weather and extend the harvest. A cold frame or tunnel can up the daytime temperature by 10 to 15 degrees and the nighttime temperature by 10 to 15 degrees.

For plants finishing their growth in the days just before and after the first frost, a covered temperature of 60 to 65ºF will allow the plant to complete its growth and come to harvest. Once cool-season crops have reached maturity under cover daytime temperatures between 30 and 40ºF are sufficient before harvesting. When winter arrives, cool-season crops at maturity will essentially hibernate or maintain. They are grown and in cool weather, they will simply sit waiting to be harvested. That’s how you can bring fresh-picked crops from your garden to the table long into winter.

Even freezing temperatures inside the cold frame in late winter do not mean the end of your winter harvest. Mature hardy vegetables will not be destroyed by hours or even a day or two of freezing temperatures as long as they are able to thaw naturally every few days. Even leaf crops such as radicchio and escarole whose outer leaves freeze and turn brown will yield a heart that is harvestable and delicious.

Also of interest:

How to Prepare a Winter Vegetable Garden