Do you still have spaces in your vegetable garden where spring-planted crops, like peas and root vegetables were pulled—or garlic? As you wait for your summer garden (tomatoes, cucumbers, peppers, etc.) to mature, think ahead to fall harvests and make a plan for succession planting. There are lots of vegetables you can still plant in August. You just need to think ahead a little. In this article, I’m going to share some of my favorite veggies to sow in my Southern Ontario garden (about USDA zone 6a), and some tips for succession planting.
The earlier you sow in August the better for some of these crops, so you can maximize their growing time before temperatures start to drop. As the days become shorter, plant growth will start to slow, too. Some years, if I’m away on vacation or busy, I’ve bent the rules a bit (i.e. planting a little later) and still ended up with some reasonable harvests. But with fall vegetable gardening, much will also depend on factors like the weather and where your garden is located. I have a couple of planting spots that are like little microclimates, so I’m able to test the limits of when I plant and how long certain plants will survive through the fall.
Choosing your vegetables to plant in August
Before we get into which vegetables to plant in August, here are some things to keep in mind:
- Amend your soil: Pulling plants out of your garden always removes a bit of soil, but the plants themselves have absorbed the nutrients. Amend your garden with an inch or two of fresh compost before succession planting.
- Read the seed packet carefully: “Days to maturity” is the key phrase you need to look for. Count backwards from your region’s frost date in the fall to see if your plants will have an opportunity to grow before the temperatures really start to dip.
- Day-length: As the days get shorter and darker in September and October, plant growth slows. It’s essential to account for this slower growth when you time the planting of fall crops and I add an extra 7 to 10 days to the ‘days to maturity’ listed on seed packets. If a turnip variety takes 40 days to go from seed to harvest, assume it needs closer to 50 days to mature.
- Plan ahead: If you think ahead, start some of these seeds under grow lights (the ones that don’t need to be direct sown), so they have even more of a head start in the garden. This is a good idea for lettuces, because many are slow to germinate in hot, dry soil. Also, make note to include extra seeds for some of these crops when you’re making your winter seed order.
- Nurture your seeds: Summer soil conditions (heat and dryness) can make it tricky for seeds to germinate. Try to keep the soil moisture consistent where newly sown seeds are planted, using the light spray nozzle on your hose, or a watering can. If you’re deep watering the rest of your garden, remember to check the bare soil areas on the days in between. And avoid deep watering these areas as you don’t want the seeds to wash away.
My favorite vegetables to plant in August
Here are a few of the veggies I sow in my summer garden.
I remember how brilliant I felt when I first thought to sow turnip seeds in the space where I had pulled out my garlic. I shared some of my favorite turnips to grow in an article, including succulent Japanese turnips. They are so delicious and can be picked when they’re the size of a walnut or ping pong ball!
Kale is another favorite green that I use in salads and stir fries, and bake into crispy chips. Most of my spring-planted kale plants are a good size by fall, so I appreciate the tender leaves of baby kale that I sow in the summer. Floating row cover protects my kale crops when temperatures really start to dip—though kale doesn’t mind a touch of frost. I’ve harvested well into November. I’ve also written about growing kale indoors if you’d really like to extend your season.
If you’d like to grow beets, look for early beet varieties, like ‘Chioggia’ and Detroit Dark Red. If things don’t go according to plan, and you’re left with minuscule beets, you can still enjoy the leafy greens.
Cilantro is one of those frustrating crops that bolt early in the late spring/early summer. I try to plant slow-to-bolt varieties, and give them a bit of shade, but they still go to seed too soon for my liking. I’ll let the seed pods open into the raised beds where they are planted. But I’ll also sow seeds in early August for guaranteed fall enjoyment.
Bok choy, in my opinion, is a stir fry superstar. I use a lot of it in my cooking, so I am always eager to plant some in August. Spring-sown crops can bolt quickly if there is a sudden hot spell, but in the fall, these leafy greens are cold tolerant. I love mini varieties, like ‘Toy Choy’ and ‘Asian Delight’.
Radishes are a quick-growing crop that can mature in as little as 21 days. They don’t love the hot weather, so you can wait until late summer—end of August, or even into September—to plant them and enjoy in early fall.
Mizuna is a mustard green that’s a new favorite. It’s got a bit of bite, and is delicious tossed into salads with other greens. Start sowing seeds for red varieties in August, knowing you can also use them as ornamental foliage in your fall containers.
Speaking of salads, it only takes about four to five weeks before you can begin to snip cut-and-come-again lettuces. I love oak leaf varieties and ‘Buttercrunch’. Lettuce seeds can be sown in late August and you can harvest the leaves through the first frost. Arugula is another fast-growing green that can be sown towards the end of August into early September. (It’s also a little fussy about the heat.) I love arugula in salads, but also as a pizza topping!
Carrot seeds can be sown in late July, early August. A favorite is the round ‘Romeo’ variety that I’ve planted in early in August with success. You can also deep mulch carrots for winter harvests if you start them soon enough.