Sowing Into a Drought: The August 2026 Heat and What It Changes
Updated August 2026 · SowWhen
The fall garden has a scheduling problem in a normal year: cool-season crops have to be started in the hottest, driest weeks of the season. In August 2026 that problem is sharper than usual. As of the July 28 U.S. Drought Monitor, about 48% of the Lower 48 was in drought — roughly 40% counting the whole country and Puerto Rico — with conditions worsening for a third straight week across large parts of the Northern Plains and Upper Midwest. The Climate Prediction Center's outlook for the first week of August favored above-normal temperatures across most of the continental United States, with the strongest signal over California, the Great Basin, the Desert Southwest, and the central and southern Rockies.
None of that changes what your zone's calendar says to plant — the August sowing windows are set by your first fall frost, and frost does not care about drought. What it changes is the technique. This guide covers the three things that actually decide whether an August sowing succeeds in a hot, dry year: getting seed to germinate, watering in a way that reaches roots, and knowing what to give up on.
Why hot soil is the real obstacle, not dry soil
Dry soil is a solvable problem — you can water it. Hot soil is not, and it is the reason August sowings fail. Several cool-season crops go thermodormant above a threshold temperature: the seed is alive and the moisture is there, but it refuses to sprout. Lettuce is the classic case, and it can shut down entirely in soil much above 80°F. Bare soil in full August sun routinely runs 15–25°F hotter than the air, so an 88°F afternoon can easily mean a 105°F seedbed at planting depth.
This is why the standard advice to "keep the seedbed moist" is only half the instruction. Watering does cool soil — evaporation is doing real work — but a single morning watering on a bare bed is dry and hot again by mid-afternoon. The fix is to shade the row until seedlings emerge, which costs nothing: a board laid flat over the row, a scrap of burlap, a piece of row cover on hoops, or simply sowing on the shaded side of an existing tall crop. Check daily and pull the cover the moment you see green, or you will trade dormant seed for leggy seedlings.
Germination reference for the August sowings
| Crop | Germinates well up to | The August problem | Tactic that works |
|---|---|---|---|
| Lettuce | ~80°F soil | Goes thermodormant; seed simply will not sprout | Sow in the evening, shade the row, or start in trays somewhere cooler and transplant |
| Spinach | ~75°F soil | Erratic, patchy emergence in warm soil | Pre-chill seed in the fridge about a week, sow slightly deeper, water to cool the bed |
| Carrot, beet, turnip | ~85°F soil | Germinate fine, but the surface crusts and dries before roots take | Board or burlap over the row until emergence; light water twice daily, not one heavy soak |
| Broccoli, kale, collards | ~85–90°F soil | Seed sprouts readily — then the seedlings cook | Start in trays in shade, transplant late in the day, water in immediately |
| Radish, arugula | ~85°F soil | Emerge easily but turn sharp-flavored and bolt under stress | Sow later in the month; steady moisture matters more than quantity |
| Garlic (north only) | Soil temp not limiting | Dry soil delays rooting before winter | Water the bed thoroughly before planting, then mulch heavily |
The pattern in that table is worth stating plainly: the brassicas are your reliable crop in a hot August, and the salad greens are not. If your beds and your time are limited this year, plant the broccoli, kale, and collards on schedule and push lettuce and spinach to a September sowing or into trays under shade.
Watering: fewer, deeper, earlier
Under drought — and under the watering restrictions that often come with it — how you water matters more than how much. Three rules cover most of it.
Water deeply and less often. A brief daily sprinkle wets the top inch and trains roots to stay there, where the soil dries out first. Established plants do far better with a long soak every three or four days that wets the soil 6–8 inches down. The exception is a seedbed before emergence: seed sitting in the top half-inch genuinely does need light, frequent water until it sprouts, and that is the one time daily watering is right.
Water at the soil, in the early morning. Overhead watering in the afternoon loses a large share to evaporation and wets foliage during the hottest hours. A hose at the base, a soaker line, or drip puts water where roots are. Early morning beats evening because leaves dry before nightfall, which matters for disease.
Mulch, then mulch more. Two to three inches of straw, shredded leaves, or grass clippings over the root zone is the highest-return hour you will spend this month: it slows evaporation, keeps soil temperature down, and suppresses the weeds that would otherwise compete for the water you are rationing. Keep it pulled back an inch from stems, and do not mulch over a seeded row until the seedlings are up.
Triage: what to prioritize when water is limited
If you are under restrictions or simply cannot keep everything alive, water in this order. First, anything newly seeded or transplanted — those plants have no root system and die fastest, and they represent the fall harvest you are trying to establish. Second, crops at a critical stage: fruit sizing on tomatoes and peppers, and anything flowering, where a moisture check costs you the yield outright. Third, established perennials and anything you would have to replace. Last, and honestly optional, is lawn.
The corresponding decision is what to let go. A spring lettuce planting that has already bolted, a cucumber vine that is more mildew than leaf, a determinate tomato that has finished its crop — pull them now. Every plant you remove stops competing for soil moisture, and clearing the bed gives you a place to plant something with a future. Tired mid-summer beds are also the place to work in compost before fall sowing: soil with more organic matter holds more water, which is the cheapest drought protection there is and the only one that compounds year to year.
If your ground is genuinely too hard to work
In the worst-hit areas the practical obstacle is not heat at all — it is that baked, cracked soil cannot be prepared into a seedbed. Two options are better than forcing it. Water the bed thoroughly, wait a day, then work it; dry soil worked hard breaks into dust and loses structure you will want back later. Or skip the bed entirely for now and start everything in trays, where you control moisture completely and can hold seedlings in shade until conditions ease. A brassica transplanted two weeks late still crops; a seed that never germinated does not.
One last note on timing. Drought does not move your frost date, so the zone-by-zone windows still apply, and if a heat wave pushes you past the end of one, check whether a faster crop still fits rather than sowing the slow one late. Radishes and arugula mature in three to five weeks and rescue a lot of Augusts. Your zone's exact dates are on your planting calendar, and Plan a Second Harvest covers the fall garden's full method once the weather turns.
Drought conditions and outlooks cited here are from the U.S. Drought Monitor release of July 28, 2026, and NOAA Climate Prediction Center outlooks for early August 2026. Conditions change weekly — check drought.gov for your county before planning a season around them.
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