Maryland Lawn Fertilizer Law: Blackout Dates and Nitrogen Caps
By Eric, TurfDial Founder · Reviewed October 19, 2026
Maryland homeowners may not apply lawn fertilizer between November 16 and March 1, and no single application may exceed 0.9 lb of total nitrogen per 1,000 sq ft, with no more than 0.7 lb of it soluble. If you fertilize a Maryland lawn, those three numbers set your whole schedule.
This guide covers Maryland only. It is the state-law example behind the State blackout dates selector in the Nitrogen Rate Calculator.
What the Maryland Department of Agriculture says
The Maryland Department of Agriculture's lawn fertilizer page states the rules for homeowners:
- Dates: "Do not apply lawn fertilizer between November 16 and March 1."
- Total nitrogen: "A single fertilizer application may not exceed 0.9-pound total N per 1,000 sq ft"
- Soluble nitrogen: the application "can include no more than 0.7 pound of soluble N per 1,000 sq ft"
- Enhanced efficiency fertilizers: they "may not be applied to lawns between November 16 and March 1 of each year."
- Annual ceiling for controlled-release products: "Enhanced efficiency controlled release products may be applied at no more than 2.5 pounds per year"
The page treats lawn care professionals separately. They "may apply nitrogen to lawns, between November 16 through December 1." That exception is not for homeowners.
What this means for your calendar
The blackout closes November 16 and reopens March 1. Your usable window is the days between those dates. For cool-season grass, fall is the main feeding season, so the November 16 cutoff is the date to plan around. The nitrogen guide says cool-season grasses are fed mainly in fall, around September and again in late fall. In Maryland, "late fall" has to land before November 16.
Why the 0.7 lb soluble cap does the real work
Two caps apply to every pass: 0.9 lb total N and 0.7 lb soluble N. The soluble cap binds first on a quick-release source, because all of its nitrogen is soluble. The quick-release vs. slow-release guide covers why urea behaves this way. Only a product with slow-release nitrogen in it can use the gap between 0.7 and 0.9.
Worked example: 5,000 sq ft with urea
Assumption: you use urea, 46-0-0, which is all quick-release.
- Soluble cap: 0.7 lb N × 5 (thousand sq ft) = 3.5 lb N.
- Convert to product: 3.5 ÷ 0.46 = about 7.6 lb of urea for the whole lawn.
- Compare the total-N cap: 0.9 lb × 5 = 4.5 lb N, or 4.5 ÷ 0.46 = about 9.8 lb of urea. You cannot reach it, because the soluble cap stops you at 7.6 lb.
So on 5,000 sq ft, 7.6 lb of urea is the most you can spread in one pass. Spreading 9.8 lb because the total cap allows it would break the soluble limit.
Check your own lawn
Enter your square footage, grass type and bag analysis in the Nitrogen Rate Calculator and choose Maryland in the state selector. It shows the blackout window and the per-application cap beside your product amount.
Scope and limits
This guide covers Maryland's homeowner rules as published on the Maryland Department of Agriculture page below. Other states and many counties and cities set their own dates and caps, so check your own jurisdiction. Rules change, so confirm against the agency page before you apply. Rates are per application, not per year, except where noted. This is informational only, not professional advice.
Last reviewed: October 2026.
Frequently asked questions
When can I fertilize my lawn in Maryland?
Any time except November 16 through March 1 for homeowners. The Maryland Department of Agriculture says "Do not apply lawn fertilizer between November 16 and March 1."
How much nitrogen can I put down at once in Maryland?
No more than 0.9 lb of total nitrogen per 1,000 sq ft per application, and no more than 0.7 lb of that soluble. On a 5,000 sq ft lawn that is 4.5 lb total and 3.5 lb soluble.
Does the blackout apply to slow-release fertilizer?
Yes. The Maryland Department of Agriculture says enhanced efficiency fertilizers "may not be applied to lawns between November 16 and March 1 of each year."
Can a lawn care company apply during the blackout?
Only in a narrow window. The page says professionals, not homeowners, "may apply nitrogen to lawns, between November 16 through December 1."