Just because summer comes to a close doesn’t mean the homegrown harvest has to end.
Written by Niki Jabbour
In my large vegetable garden, I plant new seeds and seedlings from mid-summer through early fall so that we have plenty of vegetables to harvest in autumn and even winter. And I live in Canada!
Below I outline some of my summer succession planting techniques as well as favorite crops to grow. l also share some of the season extenders that protect my crops when the temperature drops.
Cleaning out spent crops:
Before I can sow more seeds or plant more seedlings in mid to late summer I need to clean out spent vegetables.
It can be tricky to tell when it’s time to pull out a crop. Sometimes vegetables, like peas or beans, keep producing a few pods here and there and you may hesitate to pull them out. My motto is to remove vegetable plants as soon as production declines.
Amending the soil between successive crops:
We’ve all heard the saying, ‘Feed the soil, not the plant,” and this is super important when succession planting.
The soil must be healthy and fertile in order to grow a bumper crop of vegetables. I amend my beds with an inch of compost or aged manure between plantings. I also apply slow-release organic vegetable fertilizer (read the fertilizer package for application rates).
If you’re not sure of your soil fertility, get it tested.
You don’t want to apply unnecessary amendments and fertilizers. It’s a good idea to get a soil test every three to four years so you have an overview of your soil’s health.
When to plant:
Some crops, like radishes, arugula, and leaf lettuce are quick growing and ready to harvest just a month from sowing.
Others, like cabbage, Brussels sprouts, beets, and kohlrabi need more time and have to be planted earlier in the season.
So how do you know when to plant?
Read your seed packet for ‘days to maturity’ information. That tells you how much time a crop needs to go from seed to harvest. I like to build in an extra week because plant growth slows in autumn when the day-length is shrinking. Then count backward from your average first frost date and you’ll know when to plant.
What to plant:
It’s time to think about what to plant!
There is no shortage of delicious, easy-to-grow vegetables you can plant for fall and winter harvesting. I live in Eastern Canada in zone 5 and still harvest all winter long with my sneaky season extenders (see the next section). The below vegetables are some of my favorites to grow in autumn.
This gorgeous kale yields a large harvest of tender deeply curled leaves. You can grow it as a baby crop (about 40 days) or for full-sized plants (50 days). It’s also great in containers if you’re short on space. Mature plants grow just 15-inches tall but pack a LOT of leaves into that small space.
I’m a big fan of pak choi, a type of Chinese cabbage that’s very quick to grow; just a month for baby plants or six weeks for mature heads. The bright white ribs are topped with dark green leaves and Asian Delight is slower to bolt than other varieties. This vegetable adds a big crunch to autumn stir-fries.
I’ve been growing Katarina for several years now, often planting it for both spring and autumn crops. It’s the fastest-growing cabbage in my garden – by far – with four to five-inch diameter heads ready to cut 45 days from transplanting (55 days from seeding). It’s got a fantastic sweet cabbage flavor and is the perfect size for a family meal.
Bunching onions, also known as scallions or green onions are non-bulbing onions with crisp white stalks and deep green leaves. These are essential in my kitchen. Bunching Warrior is a variety that is cold hardy and can be harvested from mid-autumn and even into winter if grown in a cold frame or greenhouse.
Want a speedy crop in garden beds or pots? You can’t beat Red Kingdom mizuna! Baby greens are ready to harvest three weeks from seeding or enjoy full-sized plants in five weeks. The bright purple-green leaves have a mild mustardy flavor that adds brightness to salads or stir-fries. Sow seed every two to three weeks from late summer through early autumn for a non-stop crop.
I’ve always thought that kohlrabi was an under-appreciated veggie. It’s a member of the cabbage family and thrives in the cool temperatures of autumn. The leaves are edible but the real prize is the globe-shaped stem that is sweet and crisp. We enjoy it raw and cooked. Konan is ready to harvest 50 days from seeding or around 42 from transplanting.
My family loves the spicy flavor of fresh radishes and I’ve been growing Sweet Baby for a few years now. The roots are gorgeous: purple skin with bright white, purple streaked interiors. It’s also easy to grow with roots ready to pull in about 40 days. Sow seed often for a continual supply of high-quality radishes.
Oakleaf lettuce is cool tolerant and fast-growing – perfect for autumn salads! Sandy is an award-winning variety with 10-inch diameter heads packed with frilly, deep green leaves. You can harvest them as a baby crop just a month from seeding or give them another two to three weeks to mature to a full-sized head. Sandy is also slow to bolt and disease resistant. A perfect lettuce for the fall garden, greenhouse, or cold frame.
I’ve been relying on season extenders like cold frames, mini hoop tunnels, and a polytunnel for years.
These devices allow me to stretch my season and enjoy a crop of homegrown vegetables all winter long.
A cold frame is just a bottomless box with a clear top. I make mine from untreated local hemlock, but you can also buy cold frames, often made from polycarbonate. These capture solar energy and create a microclimate around your crops. Cold frames can extend the harvest by six to eight weeks in spring and again in autumn. They’re perfect for compact vegetables like kale, mizuna, lettuce, scallions, beets, carrots, and pak choy.
Mini Hoop Tunnel
Mini hoop tunnels are quick and easy to build. We make ours from 10-foot lengths of 1/2 inch diameter PVC conduit. These are bent over my raised beds and then covered with a row cover or sheet of polyethylene, depending on the season. They’ll push back spring by about a month or stretch the autumn harvest by four to six weeks.
Having a 14 by 24-foot polytunnel in the middle of the garden has really upped our year-round production. Not only do I get a jump on the spring planting season with extra-early greens and root crops, but we also enjoy an early crop of cucumbers, tomatoes. Once summer begins to wind down, I fill the beds with autumn crops like cabbage, scallions, kohlrabi, beets, radishes, carrots, and salad greens.
Add fertilizer and compost to your beds when starting your fall crops.
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The above cold weather ideas are intriguing to try. However I’m in NE specifically Staten Island, NY. I’d like to try something and wonder is there a chance the hoop or cold frame would work. For the past two winters we have had mild weather and no snow but who knows this year. Do you think it’s worth the effort?
Great question! I live in zone 5 in Nova Scotia (north of NY) and I use all of these season extenders in my garden to extend my harvest. A cold frame is the most effective if you’re comparing it to a mini hoop tunnel. You can use it to have salads and root crops into late autumn or even winter, depending what you’re growing. I like to grow spinach, arugula, winter lettuces, carrots, and beets for example. I have a lot of detail on cold frame growing in my first book, The Year-Round Vegetable Gardener and my upcoming book, Growing Under Cover if you were looking for more info. Good luck! – Niki