Cool Crops, Hot Results: August Planting for Zone 7

by Janet Scheren, Fairfax Master Gardener
root cropsLate summer may be hot and humid in Northern Virginia, but it’s the perfect time to start planning — and planting — for a productive fall vegetable garden. Now is the time to transition from summer’s tomatoes and cucumbers to cool-season crops that thrive in the crisp autumn air. With a typical first frost in late October, there is still have plenty of time to sow or transplant hardy vegetables and herbs that will flourish in the cooler months ahead. Whether you’re aiming to extend your season or maximize your garden’s output, August is the window of opportunity to plant fresh greens, roots and flavorful herbs for fall and even an early winter harvest.

Brassicas
Vegetables from the species Brassica oleracea are the stars of the fall garden, and August is the month to get them established. These crops prefer cool weather, full sun and fertile soils. Best of all, they actually taste better when kissed by frost. Start from transplants for best results.

Broccoli Start seeds indoors in late July or transplant seedlings by early August. Allow 60 to 70 days to mature.
Brussels Sprouts Plant early in August to allow 100 days to mature. These cold lovers continue to produce even after light frosts.
Cabbage Transplant into the garden from early to mid-August. Beat the frost by choosing early-maturing varieties.
Cauliflower A bit fussier than broccoli or cabbage, start with transplants to maximize success. Give it 60–80 days to mature.
Collards Another leafy green, it improves in flavor with frost. Sow or transplant from mid- to late August.
Kale Cold-hardy and vigorous, kale can be direct seeded from mid- to late August and harvested well into winter. It often self-seeds, so don’t be surprised if you get a volunteer crop where it was planted in previous seasons.
Mustard Greens Spicy and quick to grow, these greens mellow out after a touch of frost.

Leafy Greens
Cool-loving greens are quick to mature and offer extended harvests. Sow in succession every 7 to 10 days to ensure a continuous supply.

Arugula or Rocket This fast-growing green can be cut multiple times. Plant through September for peppery fall salads.
Lettuce Romaine and leaf types perform best. Sow frequently in small batches to avoid bolting and extend your harvest
Spinach Wait until late August or early September when soil begins to cool. Spinach can overwinter under light protection and resume growth in spring.

Root Crops
Root vegetables thrive in cool soil and are sweeter after cold weather moves in. Sow these directly into well-prepared beds and keep the soil evenly moist.

Carrot Sow early in August and allow 70 to 80 days to mature. Use mulch to retain moisture and keep the soil cool.
Radish These are the speed demons of the fall garden, maturing in just 20 to 30 days. Sow every week or two through September for ongoing harvests.
Turnip This is a root vegetable and also a Brassica. Sow in mid-August for roots and greens. Turnips tolerate light frost well and mature in about 60 days.
Beet or Beetroot Sow through mid-August. Beets mature in about 50 to 60 days. Both roots and greens are edible.

Get a Jump on Spring
Certain crops don’t mature in fall but are planted now to get a head start on spring.

Garlic While planting happens in October or early November, begin prepping your garlic bed in late August. Choose hardneck varieties for better cold tolerance.
Onion sets Overwintering onions can be planted in late August through early September. They’ll establish roots in fall and resume growth in spring.

Herbs for the Fall Garden
Don’t forget to include herbs in your fall planting plan. Many herbs thrive in the milder temperatures of late summer and early fall and can continue producing through the first frost — or even later with protection.

Cilantro or Coriander Sow in mid- to late August for flavorful leaves in fall. Cilantro bolts quickly in hot weather but thrives in cooler temperatures.
Chervil A French favorite with a subtle anise flavor, chervil likes cool, moist conditions. Sow directly in late August to early September in partial shade.
Dill Fast-growing and tolerant of light frost, annual dill can be sown in early August. It matures in 30 to 60 days, making it ideal for a fall harvest.
Fennel Both leaf and bulb types can be sown in early August. Bulbing fennel needs to mature before frost, while fronds can be harvested earlier.
Parsley Slow to germinate, parsley can be started indoors or direct-sown in early to mid-August. Once established, it’s remarkably cold-hardy and can be harvested throughout winter with light protection. Parsley is a biennial herb. It grows leaves its first year, then flowers and sets seed its second season. It is usually treated as an annual and regrown each year.
Mint Transplant or divide mint in late summer. It’s best grown in containers or isolated beds to contain its aggressive spread. Hardy and fragrant, mint holds up well in cooler weather.
Oregano Plant from transplants now so it can establish before winter. Oregano is a tough perennial in Zone 7 and offers robust spring growth.
Sage Another hardy perennial, sage benefits from August planting to root deeply before the cold sets in. It prefers full sun and good drainage.
Thyme A slow grower, perennial thyme should be planted from transplants in August. Once established, it’s extremely hardy and will thrive year after year.

Try to cool the soil in fall. August heat can inhibit germination. Use straw mulch or light shade cloth to moderate soil temperature for delicate seedlings. Use succession planting for leafy crops like lettuce, radishes, spinach and arugula, plant small batches every week or two to extend your harvest window well into fall.

Be sure to water wisely. Keep seedbeds consistently moist, especially during germination. Water early in the day to reduce disease risk. Provide frost protection if necessary. Be prepared with floating row covers, cold frames or low tunnels to extend your growing season after the first frost. And finally, control weeds. Weeds can outcompete fall seedlings. Stay vigilant and use mulch to suppress them naturally.