Fall & Winter
Snow mold on Minnesota lawns last spring: what to change this fall
Snow mold hit many Minnesota lawns last spring. Learn the fall changes that reduce it: final mowing height, leaf handling, and fertilizer timing.
Watering New Grass Seed When the Nights Are Already Cold
Late-seeded grass still needs water, but cold nights change the rules. How often to water, what time of day, and when to stop once the irrigation is blown out.
Jack · golf course superintendent·2 min read·October 5, 2026
New grass seed needs to stay moist to sprout and root. In September, that means light watering once or twice a day. In October, with nights in the 30s and 40s, the rules change.
Water less often
Cool air and shorter days mean much less evaporation. Soil that needed water twice a day in early September may stay moist for two or three days now.
The test: push a finger into the soil. If the top half-inch is still damp, skip it. Seed needs moisture, not a puddle.
Water mid-morning
- Not at night. Water sitting on blades and soil overnight in cold weather invites disease, and can freeze.
- Not too early. If it's frosty at 7 a.m., wait until the frost is off.
- Mid-morning to early afternoon gives the seedbed time to drain and the blades time to dry.
Water lightly
Short sessions keep the top layer moist without washing seed away or making mud. As seedlings get roots, water a little longer and less often to push the roots deeper.
After the irrigation is blown out
Many people have their sprinklers winterized in October. See blowing out your irrigation before the freeze. After that:
- Use a hose with a gentle spray nozzle or a sprinkler on a hose for small seeded patches.
- Disconnect the hose after every use and drain it. A hose left on an outdoor faucet can freeze and damage the faucet or pipe.
- If you have frost-free spigots, they only work if the hose is off.
When to stop
Once the ground starts freezing at night and staying cold, stop watering. Seedlings that are going dormant don't need it, and ice on the surface can smother them.
A dry, windy fall without rain is the exception. If the soil gets dry to the touch on a mild day, a light drink helps seedlings and young trees go into winter in better shape. See water trees before the ground freezes.
Don't overdo it
Constant soggy soil in cold weather rots seed, invites damping-off disease, and makes the new grass weak. When in doubt, check before you water.
Photo by bluebudgie on Pixabay.
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