Wilmington
Spot-treat55°F↑ warming
Winter weeds are up. Spot-treat them on a mild day, or in early spring before they flower.
Winter weeds are up
Delaware Weed Watch · updated Nov 3, 1:18 AM CT
When to apply pre-emergent in Delaware
Live soil temperatures for Wilmington and Dover, updated every three hours. Weeds sprout by soil temperature, not by the calendar, so the right week moves from year to year.
Delaware lawns get pre-emergent twice a year: in spring for crabgrass and other summer weeds, and in fall for winter weeds.
Spring pre-emergentNext season
Typically Mar 19 – Apr 15
Stops crabgrass and other summer weeds before they sprout.
Fall pre-emergentThis season
Typically by Aug 22 – Aug 28
Stops winter weeds (annual bluegrass, henbit, chickweed) before they sprout.
Skip it if you are overseeding this fall.
Right now · fall pre-emergent season
Winter weeds are up — spot-treat across Delaware
Soil is 53–55°F now. Spot-treat them with a post-emergent on a mild day, or in early spring before they flower.
Soil temperature by city
Soil 2 inches down, 5-day average: solid line = the last two weeks, dashed = the six-day forecast. Shaded = below 75°F, where winter weeds sprout — pre-emergent has to be down before the line gets there.
Dover
Spot-treat53°F↑ warming
Winter weeds are up. Spot-treat them on a mild day, or in early spring before they flower.
Winter weeds are up
Delaware pre-emergent calendar
Spring pre-emergent stops crabgrass. The window runs from the typical day soil warms to 50°F to the day it holds 55°F, when crabgrass starts germinating (2016–2025). Fall pre-emergent stops winter weeds: have it down a week before soil usually cools to 75°F, when they start germinating.
| City | Spring pre-emergent (crabgrass) | Fall pre-emergent (winter weeds) |
|---|---|---|
| Wilmington | Mar 30 – Apr 15 | Apply by Aug 22 |
| Dover | Mar 19 – Apr 6 | Apply by Aug 28 |
These are typical-year dates (the median of 2016–2025); any one year can run a couple of weeks earlier or later, which is what the live readings above are for. For your exact yard, check soil temperature by ZIP.
What people in Delaware are identifying
We record the state each identification comes from. Delaware's list appears here once it has at least 40 identifications spread over 7 or more days — so no single scan stands out. Until then, see the national list, or add yours:
Identify a weed from a photoWeeds to watch in Delaware this fall
Questions about Delaware
When should I apply crabgrass pre-emergent in Delaware?
Put crabgrass pre-emergent down as soil warms to 50°F, before it holds 55°F and crabgrass starts germinating. In a typical year (2016–2025) that window is Mar 30 – Apr 15 in Wilmington; Mar 19 – Apr 6 in Dover.
When should I apply fall pre-emergent in Delaware?
Winter weeds such as annual bluegrass, henbit and chickweed start germinating as soil cools to about 75°F in late summer and fall, and most come up once it is below 70°F. Have fall pre-emergent down before they start: typically by Aug 22 in Wilmington; by Aug 28 in Dover. Skip it if you are overseeding this fall, because it stops grass seed too.
What is the soil temperature in Delaware right now?
As of Nov 3, 1:18 AM CT: Wilmington 55°F, Dover 53°F (5-day average, about 2.4 inches down). Winter weeds are up — spot-treat across Delaware.
How the readings and dates are made, and their limits: Weed Watch method. Soil data: Open-Meteo.com (CC BY 4.0); typical dates: NASA POWER.