Rockville, MD Lawn Care Calendar
In a typical year, put down crabgrass preventer in Rockville between Mar 27 and Apr 21. The best time to overseed is between Aug 24 and Oct 13. The last spring frost usually comes around Apr 11. Most lawns here are cool-season grass (tall fescue, Kentucky bluegrass, ryegrass).
Typical lawn care dates in Rockville
| Task | Typical window |
|---|---|
| Crabgrass preventer (pre-emergent)Crabgrass sprouts once soil stays above 55°F. Apply when soil reaches 50°F, before that happens. | Mar 27 – Apr 21 |
| Spring fertilizerA light feeding once soil warms past 55°F and the grass is actively growing. | Apr 14 – May 19 |
| Overseeding & seedingLate summer to early fall: seedlings need about 6–10 weeks of growth before the first frost. | Aug 24 – Oct 13 |
| Fall fertilizerThe most important feeding for cool-season grass, from early fall until soil cools to about 45°F. | Sep 16 – Nov 19 |
Median dates, 2016–2025, from NOAA weather data for Rockville. This year's dates can differ by a few weeks.
Month-by-month lawn care in Rockville
- JanuaryNo treatments due; mow as needed.
- FebruaryNo treatments due; mow as needed.
- MarchCrabgrass preventer (pre-emergent)
- AprilCrabgrass preventer (pre-emergent)Spring fertilizer
- MaySpring fertilizer
- JuneNo treatments due; mow as needed.
- JulyNo treatments due; mow as needed.
- AugustOverseeding & seeding
- SeptemberOverseeding & seedingFall fertilizer
- OctoberOverseeding & seedingFall fertilizer
- NovemberFall fertilizer
- DecemberNo treatments due; mow as needed.
Soil temperature in Rockville by month
Average soil temperature 4 inches down, estimated from 2016–2025 weather. It bottoms out in January at 35°F and peaks in July at 78°F. Crabgrass preventer goes down when it reaches 50°F, usually around Mar 27.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 35°F | 38°F | 45°F | 55°F | 63°F | 72°F | 78°F | 76°F | 70°F | 59°F | 47°F | 38°F |
Rockville lawn timing, year by year
Over the last 10 years, soil in Rockville reached 50°F, the signal for crabgrass preventer, as early as Mar 10 (2016) and as late as Apr 13 (2018): 34 days apart. A fixed calendar date can't follow that, which is why the report above uses this year's soil temperature. Between the typical last spring frost (Apr 11) and first fall frost (Nov 7), the growing season lasts about 210 days.
| Year | Crabgrass window opened | Last spring frost | First fall frost |
|---|---|---|---|
| 2025 | Mar 17 | Apr 10 | Nov 11 |
| 2024 | Mar 14 | Mar 26 | Nov 13 |
| 2023 | Apr 4 | Apr 9 | Nov 2 |
| 2022 | Mar 19 | Apr 11 | Nov 14 |
| 2021 | Mar 25 | Apr 22 | Nov 3 |
| 2020 | Mar 28 | May 10 | Nov 18 |
| 2019 | Apr 7 | Apr 3 | Nov 2 |
| 2018 | Apr 13 | Apr 18 | Oct 22 |
| 2017 | Apr 3 | Mar 24 | Nov 11 |
| 2016 | Mar 10 | Apr 11 | Oct 26 |
Estimated from daily temperatures for Rockville. A dash means it didn't happen that year.
Frequently asked questions
When should I apply pre-emergent in Rockville?
In a typical year, between Mar 27 and Apr 21. Put it down when soil reaches 50°F, before it stays above 55°F and crabgrass starts sprouting. Early springs move this up by a week or more, so check this year's soil temperature above.
When is the best time to plant grass seed in Rockville?
Early fall, typically Aug 24 – Oct 13, while soil cools from 65°F toward 50°F.
When is the last frost in Rockville?
The median last spring frost is Apr 11 and the median first fall frost is Nov 7 (2016–2025).
How long is the growing season in Rockville?
About 210 days, from the median last spring frost on Apr 11 to the median first fall frost on Nov 7 (2016–2025).
Lawn care guides
More Maryland lawn calendars
Nearby cities in other states
- Washington, DC 13 miles away · crabgrass preventer Mar 14 – Apr 15
- Arlington, VA 14 miles away · crabgrass preventer Mar 14 – Apr 17
- Alexandria, VA 20 miles away · crabgrass preventer Mar 11 – Apr 9
- Lancaster, PA 80 miles away · crabgrass preventer Apr 8 – Apr 24