Best crabgrass preventer, by what it actually asks of you

Most lawns with a crabgrass problem do not have a crabgrass product problem. They have a mowing height problem, a thin-turf problem or a watering problem, and our weed control guide puts those first on purpose. This page is for the reader who has read that, fixed what they can and still wants the bag — and the useful comparison between the three bags is not what they kill. It is what they ask you to carry.

The short answer

The three, on published figures

Read the fourth column top to bottom. Three products sold on the same shelf for the same month of the year, asking for 3 lb, 2 lb and 20 lb of granules per thousand square feet. That spread is the finding, and it is the thing that decides how many trips to the car your Saturday involves.

What ten times the rate means in bags

1. Preen Lawn Crabgrass Control — the one with a second chance

Preen publishes 0.19% dithiopyr (Dimension), a 15 lb bag covering 5,000 sq ft, application in spring or fall before germination, post-emergence effectiveness up to four weeks after crabgrass has germinated, up to four months of control, a 40-plus weed list and a safe-grass list that runs to seven warm-season and five cool-season species including creeping bentgrass.

Who it is for: anyone who is not certain they will hit the window. Soil temperature moves with the weather and most people apply pre-emergent a week or two late; this is the only product here that is still worth putting down when you do. It is also the only one safe on creeping bentgrass, which the Scotts product explicitly excludes.

Who should skip it: anyone who tracks soil temperature and applies on time. You are paying for a post-emergence window you will not use, and Scotts treats a third more area per pound.

#ad Check the Preen Lawn Crabgrass Control, 15 lb price on Amazon — how we're funded.

2. Scotts Halts — the most area per pound, and a fall list

Scotts publishes pendimethalin as the active ingredient without a percentage, one 20.12 lb bag covering 10,000 sq ft, early spring application on a dry lawn for season-long control, a separate August-to-October fall window, safety on all lawns and grass types except Dichondra and Bentgrass, a seven-species spring weed list, a five-species fall list including moss (except in California) and Poa annua, and the plain statement that it does not control mature crabgrass or other existing weeds.

Who it is for: the reader with a larger lawn and a calendar. At about 2.01 lb per 1,000 sq ft it is the lowest material volume here, and the published fall window with its own distinct weed list is genuinely a second product inside the same bag — Poa annua and henbit are autumn germinators and neither of the other two makers names them.

Who should skip it: anyone with a bentgrass or Dichondra lawn, which Scotts excludes by name; and anyone who has already seen crabgrass this year, because Scotts tells you in writing that this bag will not help.

#ad Check the Scotts Halts Crabgrass & Grassy Weed Preventer price on Amazon — how we're funded.

3. Espoma Organic Weed Preventer — if no synthetic is allowed

Espoma publishes 100% corn gluten meal, a 25 lb bag, 20 lb per 1,000 sq ft for weed prevention (covering up to 1,250 sq ft) or 10 lb per 1,000 sq ft for feeding only (up to 2,500 sq ft), two applications a year in early spring and early fall, application to a dry recently mown lawn with a drop or broadcast spreader, light watering if no rain is expected within 24 hours, re-entry for children and pets after application, and a clear exclusion for seeding and over-seeding.

Who it is for: the reader for whom a synthetic pre-emergent is not an option — a household rule, a rental agreement, a certification, a conviction. On that basis it is not the third choice on this page; it is the only choice, and it is a real product rather than a gesture. It also adds nitrogen while it works, which neither other product does.

Who should skip it: anyone over about a quarter acre, for the reason in the arithmetic above — 218 lb of granules, twice a year. And anyone expecting herbicidal control: corn gluten suppresses seed establishment, Espoma does not claim more, and we will not claim more on its behalf.

#ad Check the Espoma Organic Weed Preventer Plus Lawn Food, 25 lb price on Amazon — how we're funded.

Who should not buy any of these

• Anyone overseeding this year. A pre-emergent and new seed are mutually exclusive in the same season on the same ground. Pick one.
• Anyone who has not raised their mowing height. Crabgrass is a sun germinator and a taller canopy shades it out. Free, and it works on next year's seed bank as well as this year's — the mowing height guide has the numbers.
• Anyone whose crabgrass is already seeding. By late summer the plant has done its damage and dropped next year's seed; a pre-emergent applied now is for next spring, not for the plant you are looking at.
• Anyone without a spreader. Every rate on this page assumes even distribution, and hand-scattering a pre-emergent produces stripes of overdose and gaps of nothing. See spreader settings and our EdgeGuard DLX review.

What we cannot tell you

We have not applied any of these products or measured a result. Two of the three publish no active-ingredient percentage, so for Scotts and Espoma we cannot tell you how much chemistry is actually reaching the soil — only how much granule. None of the three publishes a soil-temperature trigger, which is the only correct way to time a pre-emergent, so the timing advice on this page comes from our own weed control guide rather than from any maker. Neither Scotts nor Espoma publishes a tested time to effect. Scotts publishes no grass-type list beyond its two exclusions, and BioAdvanced-style re-entry statements appear only on the Espoma page. Crabgrass pressure also varies enormously with your own soil seed bank, which no product can know and no test we are aware of will tell you. And the dollar comparison that would finish this page properly is one we deliberately do not print, because prices move daily and a stale number is worse than none.