Most home gardens stop planting in early summer and treat August as the wind-down month. This is a missed opportunity. The 6-8 weeks between mid-August and first frost are perfect for a second round of cool-season crops, many of which produce better in autumn than they did in spring.
Cool autumn weather, declining day length, and the lessons of the first half of the season combine to make autumn the easiest vegetable gardening of the year. We have shifted to a strong second-season program over the last few years; some of our best harvests come from August and September plantings.
Why autumn crops often produce better
Several conditions favor cool-season crops grown for autumn harvest rather than spring harvest.
Steady cooling versus sudden warming. Spring brings heat waves that bolt cool-season crops before harvest. Autumn temperatures decline gradually, giving plants weeks of ideal cool conditions to mature.
Lower pest pressure. Most garden pests peak in mid-summer and decline by autumn. Cool-season crops grown in autumn face significantly less aphid, cabbage worm, and flea beetle pressure than spring versions.
Frost sweetening. Several autumn crops actually improve after light frost. Brussels sprouts, kale, collards, and parsnips all develop sweeter flavor after the first frost converts their starches to sugars.
Less competition for garden space. By August, summer crops have been producing for weeks and some beds are opening up as early crops finish. The autumn plantings slip into space that would otherwise sit empty.
The six best autumn crops
These crops produce reliably from August or September plantings in zones 5-7.
- Kale. Plant transplants in mid-August. Harvest from October through hard freeze, often into December under row cover. Sweeter after frost.
- Spinach. Direct seed in late August. Harvest from late September through November. Cold-tolerant varieties (Bloomsdale, Winter Bloomsdale) overwinter in many zones.
- Lettuce. Direct seed in mid-August through early September. Harvest from late September through November.
- Beets. Direct seed in early August. Both greens and roots are harvest-ready by October.
- Carrots. Direct seed in early August. Harvest from October through December (mulched).
- Garlic. Plant cloves in October for next summer’s harvest. The original autumn planting crop.
The planting calendar (zone 6)
Specific dates for zone 6 (most of the central and mid-Atlantic US):
- Early August: direct seed beets, carrots, leeks (from transplants), Swiss chard
- Mid-August: direct seed kohlrabi, fall radishes, lettuce, spinach; transplant kale, collards, broccoli
- Late August: direct seed more lettuce, spinach, arugula, mache, hardy greens; transplant any remaining brassicas
- Early September: direct seed last lettuces, spinach for late autumn harvest; plant cover crops on empty beds
- Mid-September: direct seed hardy greens (mache, claytonia) for late autumn
- October: plant garlic for next summer; protect tender plants with row cover
Extending past frost with row cover
Row cover (frost cloth, the lightweight white fabric available at garden centers) extends autumn harvest by several weeks beyond the first frost date. The cover traps heat and protects plants from frost damage down to about 25-28F.
For autumn crops, plan to install row cover in late October. Drape directly over the plants and secure the edges with rocks, soil, or landscape staples. Hoops give extra room for taller plants but are not essential for ground-hugging crops like lettuce and spinach.
Under row cover, lettuce, spinach, kale, and other hardy greens continue to produce well into November or early December in zones 6-7. Some, like spinach and mache, survive winter under row cover and resume growing in late winter, providing some of the earliest spring harvests.
Cold-tolerance ranges
Different crops handle different levels of cold. Knowing the limits helps you plan what to plant when.
- Frost-sensitive (damaged by 32F): basil, cucumbers, tomatoes, squash – protect or harvest before frost
- Light-frost-tolerant (handles brief 28-32F): lettuce, beans, peas – row cover for sustained cold
- Hardy (handles 25-28F): spinach, beets, carrots, broccoli, cabbage – protect at sustained cold
- Very hardy (handles 20-25F): kale, leeks, parsnips, Brussels sprouts – often unaffected by typical frost
- Winter-hardy (handles below 20F): garlic, mache, claytonia, parsley – survives winter outdoors with mulch
The cleanup-and-plant routine
For each bed coming out of summer production, the autumn planting routine takes about 30 minutes per bed.
Pull the spent summer crop. Top with 1-2 inches of fresh compost. Lightly rake to incorporate. Direct seed or transplant the autumn crop following normal spacing.
Water thoroughly. Continue watering more frequently than mid-summer because the new seeds need consistent moisture to germinate in warm late-summer soil. After plants are established (1-2 weeks), water normally.
Mulch lightly to retain moisture during late-summer heat. As temperatures cool, normal watering frequency works.
Late-season sowing turns an empty late-summer garden into a productive autumn harvest extending well past the first frost. The work is small (planting in beds that were already cleared), the pest pressure is low, and the crop quality is often better than spring versions. Plan for autumn planting in your calendar; the second half of the gardening year deserves attention equal to the first.
What to do with bolted spring crops
Late-season planting often happens in beds where spring crops have bolted and gone to flower or seed. The temptation is to pull everything and start fresh. A better approach uses some of what is already there.
Bolted lettuce produces hundreds of seeds from each plant. If you have a favorite variety, let one or two plants finish their cycle, collect the seeds (they look like dandelion fluff once dry), and you have next year’s lettuce supply for free. Cilantro bolts produces coriander seeds, which keep their flavor for two years and start next year’s plants reliably.
Plants pulled before seed maturity become high-nitrogen compost ingredients. Chop them, mix with browns, and they break down into excellent soil amendment within months. The compost from spring bolted crops is some of the richest we produce all year.
Whatever you do, do not leave bolted plants standing all season. They draw nutrients from the soil without producing anything, shade out neighbors, and harbor pests that will move onto your fall crops. Clear them within a week or two of identifying that the season is over for them.
Related reading from the journal
Other entries worth your time: Pollinator-Friendly Vegetable Garden Design, Building a Raised Bed That Will Last Twenty Years, and Seasonal Planting Calendar for Cool-Climate Gardens.
Further reading
Trusted references we consulted while researching this piece. All external.
