Zone by Zone: What To Plant in August

Kevin's Note: This is a guest post from Garden Collage, good friends of mine over in New York! Enjoy.

August is typically associated with the end of summer and the upcoming harvest season. But we firmly believe that August is actually the perfect month to sneak in one last round of planting before first frost sets in and the cold weather arrives for good.

Below, we’ve curated our August planting picks for each of the USDA’s Plant Hardiness zones. (If you’re not sure what zone you live in, type in your zip code here.) We’ve omitted Zones 1, 2, and 11-13, as most of the United States population lives in Zones 3 through 10.

Zone 3

August Spinach

August Spinach. source

Gardeners in Zone 3 (which covers the central parts of the border with Canada) should plant a last round of spinach (Spinacia oleracea) before winter sets in for good. Though its tender green leaves may seem delicate, spinach is a surprisingly tough plant in cold weather (it can survive temperatures as low as 20ºF if well-established) and the leaves pack a punch when it comes to nutrients.

Plant spinach at least one foot apart, so that there’s space for it to fill out. Plant is rich, well-drained soil. Spinach seeds won’t germinate if the soil is too dry, so make sure-- especially at the outset-- that your soil stays damp. A spot with light shade is best for spinach; aim for three to four hours of sun a day. If your leaves are turning yellow, it may be a lack of nitrogen in the soil, so try adding a sprinkling of coffee grounds around the base of the plant.

Zone 4

August Corn Salad

August Corn Salad. source

Located through the Northern Rockies and in the far Northeast (think: the weather in Minneapolis), Zone 4 should plant mâche (Valerianella locusta), a type of sturdy lettuce first cultivated in 17th century France. Plant as August temperatures start to cool off (high 60s is ideal) and don’t be concerned by mâche’s slow germination period (typically 10-14 days), as mâche prefers a temperature range around 40º to 70º F.

Sow seeds 1” apart in moist soil and mulch thoroughly to protect from heat and weeds. Pick a spot with some sun in the morning and shade in the afternoon (avoid any kind of intensely hot weather with mâche). Snails and slugs are the biggest challenge to growing mâche; hollowed-out citrus peels offer some relief by warding off snails and slugs. (Just be sure to place a few rinds strategically around where you are growing the mâche.)

Zone 5

August Beets

August Beets. source

For those in Zone 5 (which represents the cooler parts of the Northeast like Albany, and stretches in a band from Chicago to Denver), beets (Beta vulgaris) are an ideal vegetable to plant in August. Though they are native to the mild Mediterranean, beets have long been recognized as a cold-weather vegetable (they are, after all, the critical ingredient in borscht).

Plant seeds in well drained with 3” to 5” of space between, in a spot with full sun. As they grow, beets need plenty of phosphorus; you may need to invest in phosphate rock if your soil is deficient. Come spring, if the problem persists, try planting phosphorus-fixing alfalfa. Fungus is often the biggest setback to beets so (to emphasize again!) make sure your soil stays well drained and isn’t cold and damp.

Zone 6

August Broccoli

August Broccoli. source

For gardeners located in Zone 6 (which crosses several zones from Philadelphia all the way out to parts of the West), broccoli (Brassica oleracea) offers a green transition into fall. Broccoli is a cold weather crop-- but too cold and the broccoli won’t not develop properly, which is why August (with the heat beginning to wane) is the ideal time to get started. (You might even try planting Romanesco!)

Plant broccoli 16” apart in rich soil where the plants will get full sun. Water thoroughly so the plants are always kept moist. You can also mulch to help cool the soil down and retain moisture (plus, of course, mulch has the bonus of tamping down on weeds). Aphids are the most frequent broccoli threat, but a solution of neem oil (mix 1 tsp with ½ tsp soap and 1 liter water) can be an effective deterrent.

Zone 7

August Carrots

August Carrots. source

Zone 7-- referring to the Ohio Valley and the inland areas of the West-- is still quite hot in August but you can squeeze a quick planting of carrots (Daucus carota subspecies sativus) outdoors to harvest in the fall. As with other root crops, carrots should be situated in loose, neutral pH soil with plenty of room to grow downwards. Be sure your carrots get at least 1” of water a week-- either from rain or by hand-- and that the water thoroughly saturates the soil. Carrot root flies (the most common carrot pest) tend to lay their eggs in August (if you can delay planting in September this helps). To keep them from reaching you crops, use a fleece sheet to cover the carrots and surrounding soil. (And remember: you can eat carrot greens!)

Zone 8

August Squash

August Squash. source

Encompassing the upper parts of the South and coastal regions in the Pacific North West, Zone 8 should prepare a planting of yellow summer squash (Cucurbita pepo) during the brief window of opportunity in August. We especially like yellow summer squash because it tends to produce a lot compared to other varieties of summer squash. Soil for yellow summer squash should be well drained and seedlings should be spaced 4” to 6” apart.

Locate the plants in a part of the garden with full sun, but try to wait for a cloudy day to transplant seedlings, as immediate harsh sun can cause them to wilt. Be sure your summer squash gets at least an inch of water, once a week, and that this water sets in deep to the soil. To avoid any of the common vine diseases summer squash is often plagued by, inquire at your local nursery for resistant cultivars or look for resistant seeds online.

Zone 9

August Cherry Tomatoes

August Cherry Tomatoes. source

For August, Zone 9 (California and the South) can start their fall cherry tomatoes (Solanum lycopersicum var. cerasiforme) indoors and move them outside as the month progresses and cools slightly. It’s a short window of time for cherry tomatoes, which are often thought of as being planted in the spring and harvested during the summer, but they do well in Zone 9’s still-warm temperatures of late summer and early fall. (We love the Super Sweet 100 cherry tomato.)

When preparing soil, make sure it is rich and well drained, and space seeds or seedlings at least a foot apart. Cherry tomatoes a minimum six hours of sun, so be sure to place them in a spot that receives full sun. Since the plants are in full sun, also be sure to water every few days to ensure the soil remains damp. Squirrels and other small garden creatures (even birds) often snack on cherry tomatoes, so try draping your plants with netting to keep them at bay.

Zone 10

August Garlic

August Garlic. source

In Zone 10 (the hotter parts of Southern California and the tip of Florida) at this time of year, it is predominantly a time for harvesting. However, Zone 10 gardeners can start planting their garlic (Allium sativum), and can continue to plant garlic through the winter months. Garlic is a relatively tolerant plant and can be planted in different soil types, but is most successful in rich, well drained soil. Give garlic a wide berth when planting in your garden; you should plan to leave 6” to 8” between cloves and to leave room below (about a foot).

Cloves should be placed a little less than half a foot below the soil level, in full sun, and the soil should be kept moist (plan to water every few days, a little more than once a week). Since garlic is a natural pest repellant, it can pretty much take care of itself. The most common issue with garlic is white rot, a fungus that lives in the soil. While there’s not much that can be done for plants plagued by white rot, rotating plants through your garden can help minimize its occurrence.​

Get a head start on your fall garden by learning what to plant in august for your particular USDA Hardiness Zone.
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