Once the summer solstice passes, the days begin to grow shorter, and although the earth continues to warm well into August in the Northern Hemisphere, the gardening days are on the decline. But they don't have to be! With the proper planning, you can harvest cool weather crops for many months in fall and early winter. So plan for your fall crops and a big harvest that extends through the seasons.
Determine Your Last Frost Date and Hardiness Zone
Work backwards from this date. You may want to take into consideration any season-extending methods like a high tunnel or floating row cover that you are using, and determining the date that your crops, with these methods in place, will experience frost.
You will also want to find your hardiness zone and make sure that what you're growing is appropriate for your zone. The zone finder below explains a bit about what zones are and how they can be helpful for farmers and gardeners. Basically, your zone gives you a tool for comparison of your growing temperatures and conditions compared to other areas of the country, and can be a good guide for finding plants that do well in your region. It is just a tool, though, and has some limitations which are discussed on the zone finder page.
Choose Cool-Weather Crops
The crops that grow best in colder temperatures are definitely going to make the top of your list for summer-to-fall planting. You won't be planting tomatoes in October in northern regions, for example! There are plenty of delicious and marketable choices of vegetables that grow well in cooler weather.
- Beets. Beets can tolerate light frosts and freezes, and can be planted up to six to eight weeks before the last frost.
- Broccoli. Broccoli prefers temperatures in the 60 to 65 degree F range for best development of broccoli heads. It is best harvested after a few light frosts.
- Brussels sprouts. Brussels sprouts actually taste better after they've experienced a frost or two. Many farmers like to transplant brussels sprouts in late summer and harvest them in the early winter, after it snows.
- Cabbage. Cabbage takes roughly two months to mature. The seeds germinate in soil as cool as 50 degrees, making them a good one to plant even in cool fall weather. But you can start some in midsummer too.
- Carrots. Carrots also take a couple of months to mature and can be overwintered in a high tunnel or with floating row cover. They taste best harvested after first frost but before the soil freezes, because that makes it pretty tough to dig them out.
- Kale. Kale, like brussels sprouts, gets a sweeter taste after a frost. Plants mature in about two months, but you can plant later and harvest baby kale. Kale's an excellent choice for overwintering.
- Lettuce. Lettuces can be cold-tolerant but don't enjoy snow atop their leaves, so floating row cover can really help here. Lettuce prefers cool soil for germination.
- Peas. Peas are usually thought of as a spring crop, but they do just as well in autumn. You can plant them in late summer when temperatures have dropped because they germinate in soil as low as 40 degrees F.
- Spinach. Another greens variety that likes cool temps for germination, late summer is a great time to plant some spinach.
- Swiss chard. Yep, again, chard will respond best to cool soil temperatures. It's a great candidate for overwintering in high tunnels or under floating row cover.
Plant to Maximize Remaining Frost-Free Days
Organize your crops by number of days to maturity. Those crops that have the longest growing times and the least cold tolerance should be planted earlier in the summer than those that grow more quickly and tolerate frost better. You can use these techniques in conjunction with a more comprehensive succession planting program to harvest crops well into the winter months, even with snow on the ground! If you are able to use a high tunnel, you will gain even more frost-free growing days.