What to Plant in August: Fall Crops That Beat the First Frost

August is the month the fall garden actually goes in the ground. July was for starting brassicas in trays and ordering seed; August is for getting them in the ground while the frost math still works. A week of procrastination in August costs more than a month of it in May.

The core moves are the same in every temperate zone: get July’s broccoli and cabbage starts into the ground, direct-sow the fast roots, and restart lettuce and spinach as the heat breaks. If you never started brassicas indoors last month (the July guide covered it), buy transplants from a nursery. No shame in it — the calendar doesn’t care.

Here’s what to plant in August, zone by zone.

Zones 3-4: Fast Greens and Cover Crops

First frost: September 1–15

You have four to six weeks left. That rules out almost everything except the sprinters — but the sprinters are worth planting.

Direct sow the first week of August:

• Radishes (25-30 days — you can fit two rounds)
• Spinach (35-40 days, and it shrugs off the first light frosts)
• Baby lettuce and arugula (30 days to cutting size)
• Turnips for greens (30 days; treat any roots as a bonus)

Sow cover crops as beds empty:

• Winter rye — germinates in cooling soil, holds beds all winter
• Oats — winterkills in zones 3-4 and leaves a ready-to-plant bed in spring
• Field peas mixed into either for nitrogen

Maintenance focus:

• Top your tomatoes in mid-August so the plant ripens what’s already set instead of making new fruit that won’t finish
• Keep row cover within reach — frost in the first week of September is normal here

Pro tip: Sow one bed of spinach in the last week of August and leave it under row cover through winter. The plants go dormant small, wake up in March, and give you harvests three to four weeks before anything you sow in spring.

Zones 5-6: Transplant Month

First frost: September 15 – October 15

The brassicas you started indoors in July go in the ground now. Miss mid-August and a 65-day broccoli runs out of season before it heads up.

Transplant by August 15:

• Broccoli, cauliflower, cabbage from July starts
• Kale, collards — frost improves the flavor of both
• Kohlrabi (45-60 days, one of the most forgiving fall crops)

Direct sow the first half of August:

• Carrots — 58-60 day fall varieties like Napoli, in the ground by August 10
• Beets (50-55 days)
• Turnips (50 days for full roots)
• Bush beans — zone 6 only, first week of August, 50-day varieties like Provider

Direct sow late August, as heat breaks:

• Lettuce and spinach, succession every 10 days into September
• Radishes, bok choy, tatsoi
• Cilantro — the fall crop is better than the spring one because it stops bolting

Maintenance focus:

• Water new transplants daily for their first week; August heat kills more fall brassicas than frost ever will
• Pull exhausted cucumbers and summer squash — open beds are fall real estate

Pro tip: Carrot seed germinates badly in hot August soil. Lay a board or wet burlap over the row after sowing, check under it daily starting at day 5, and pull it the moment you see sprouts.

Zones 7-8: Last Call for Beans

First frost: October 15 – November 15

August in zones 7-8 is two gardens at once — summer crops still producing while the fall garden goes in around them. It’s also the last month for anything warm-season.

Direct sow:

• Bush beans — last call: in by August 10 in zone 7, August 20 in zone 8 (50-55 day varieties)
• Carrots, beets, turnips for fall harvest
• One more round of summer squash and cucumbers in zone 8, in by August 10

Transplant:

• Fall tomatoes — in the ground by August 15, determinate varieties so they finish before frost
• Broccoli, cauliflower, cabbage — mid-August in zone 7, late August in zone 8, under 30% shade cloth for the first week

Direct sow late August:

• Kale, collards, mustard greens
• Radishes and turnips
• Hold lettuce and spinach until soil cools — see the pro tip

Pest watch:

• Harlequin bugs and cabbage worms find brassica transplants within days — row cover from day one
• Spider mites peak in August heat; blast leaf undersides with water before reaching for anything stronger

Pro tip: Spinach won’t germinate in soil above 85°F, and August soil in zones 7-8 is well above it. Fold the seed into a damp paper towel inside a bag, refrigerate for 5-7 days until the root tips barely show, then plant. Germination goes from spotty to near-total.

Zones 9-10: The Second Season Begins

First frost: early December in zone 9; zone 10 rarely freezes

July was planning; August is execution. The transplants you started in early summer go out as nights ease, and the best growing months of the year are ahead.

Transplant late August:

• Tomato round two — determinate and cherry types from your June/July starts
• Peppers and eggplant for fall and winter harvest

Keep going:

• Spring pepper plants are worth nursing through — an established plant will out-produce a new transplant when it sets again in October
• Okra, southern peas, yard-long beans are still in their element

Start indoors (late August, in air conditioning):

• Broccoli, cauliflower, cabbage for September–October transplant
• Lettuce for October beds — if trays are new to you, the seed starting guide covers the setup

Zone 10 specifics:

• Still peak hurricane season — keep trellises staked and harvest ahead of any named storm
• Sweet potatoes, calabaza, and tropical herbs carry the garden until October planting opens up

Pro tip: Don’t judge an August tomato transplant by its September flowers. Blossoms drop when nights stay above 75°F — that’s normal, not failure. Keep the plant healthy and it loads up with fruit the week nights cool off.

August Planting Checklist

Universal August tasks no matter where you garden:

1. Transplant July’s brassica starts — by mid-August in zones 5-7, late August in zone 8
2. Direct-sow fast roots — carrots and beets early in the month; turnips and radishes almost anytime
3. Restart lettuce and spinach — late August as heat breaks, then succession every 10 days
4. Sow cover crops as beds empty — rye or oats; a bare bed loses topsoil all winter and feeds nothing
5. Water new transplants daily — for the first week minimum; heat is the killer this month, not frost
6. Log planting dates — next August you’ll want the exact dates that worked, not a guess

Track Your August Planting

Fall planting is count-back math, and the math starts from your first frost date. If you don’t know yours, start with when to plant vegetables by zone. For the full crop-by-crop fall breakdown — days to maturity, frost tolerance, and last-sow dates per zone — see the fall vegetable planting guide.

Check your zone’s detailed planting schedule:

• Zone 5 Planting Calendar — Chicago, Columbus, Boston
• Zone 6 Planting Calendar — Philadelphia, Nashville, Portland
• Zone 7 Planting Calendar — Charlotte, Atlanta, Dallas
• Zone 8 Planting Calendar — Austin, New Orleans, Sacramento

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