The best time to apply crabgrass preventer to a Minnesota lawn is in spring when soil temperatures rise to 55℉ for 2–3 consecutive days. Calendar timing for crabgrass preventer in Minnesota is usually early to mid-April.
Not only is proper timing critical for crabgrass preventer performance, but there are also several other factors that lead to success. Make sure to choose the best crabgrass preventer for you, distribute it evenly throughout the lawn, and water it in to ensure it creates a subsurface barrier to kill germinating crabgrass seeds.
Why Soil Temperature is Important for Crabgrass Preventer Timing
Crabgrass preventer works by killing seeds in soil just as they begin to sprout. Crabgrass preventers and other pre-emergent herbicides won’t kill dormant seeds or established plants. Because crabgrass seeds begin to germinate at 57℉, it is essential to apply crabgrass preventer in Minnesota just as the soil nears temperatures that encourage seed germination.
- Crabgrass preventer only kills seeds as they germinate.
- Crabgrass seeds begin to germinate when soil temperatures rise to 57℉ in spring.
- Crabgrass preventer does not kill dormant seeds.
- Crabgrass preventer does not kill established weeds.
- Apply when soil temperatures approach germination point for crabgrass.
Soil temperature is the best gauge for timing your crabgrass preventer application. Because yearly weather patterns vary, you’ll get the most out of your lawn care efforts by timing application based on soil temperature, not the calendar.
How to Check Minnesota Soil Temperature for Free
You can check soil temperatures in your area without setting foot outside. Free online maps provide recent soil temperatures for your region. This way, you can pinpoint your area and monitor soil temperatures in spring.
- Use this free online soil temperature map.
- Consult this Minnesota Department of Agriculture soil temperature map.
Although your yard’s soil temperatures may differ slightly from the regional average on a map, these resources are accurate enough to guide crabgrass preventer application. It also saves you the cost and effort of buying and using a soil thermometer.
Average Timing for Crabgrass Preventer in Minnesota
On average, soil temperatures are optimal for crabgrass preventer application in the Minneapolis area by early to mid-April. Similar to nearby states like Wisconsin, April 15th is a standard date to spread crabgrass preventer in the region.
However, Minnesota temperatures vary by region and by year. In northern regions, or during years with long winters, temperatures may not be ideal for crabgrass preventer application until late April or even early May. Following a mild winter, early April might be the best time to spread crabgrass preventer in your yard.
Best Minnesota Crabgrass Control Products
There are several crabgrass preventers on the market that are great choices for use on Minnesota lawns. The one you choose depends on your needs and preference. Below are our top picks.
Scotts WeedEx provides excellent crabgrass prevention that won’t break your budget. It’s well-reviewed and produced by a longstanding, trustworthy manufacturer.
If you have stubborn crabgrass that resists regular preventers, try Preen. This pre-emergent herbicide stops seeds from sprouting for up to 3 months—twice as long as ordinary crabgrass preventers. It will succeed where others have failed.
Crabgrass Preventer Plus Fertilizer
Why fertilize your yard and spread crabgrass preventer in two separate steps? Scotts Turfbuilder with Crabgrass Preventer is a blend of lawn food and pre-emergent herbicide. It’s an efficient way to stop weeds from sprouting and boost your lawn’s performance. A thicker, healthier lawn always resists more weeds.
Natural Crabgrass Preventer for Minnesota
You can prevent crabgrass and other weeds from sprouting in your lawn without resorting to chemical herbicides. Espoma Weed Preventer is a natural, organic weed preventer made from 100% corn gluten meal.
Corn gluten meal can be spread instead of a chemical crabgrass preventer. Corn gluten meal naturally absorbs moisture, drying out seeds as they germinate, killing them. If you want a chemical-free yard, give this sustainable lawn care method a try.
How to Apply Crabgrass Preventer on a Minnesota Lawn
Once you’ve chosen a crabgrass preventer, it’s time to apply. In order to get the most out of the hard work you put into lawn maintenance, follow these steps for crabgrass preventer application:
- Apply when soil temperatures reach 55℉ in early/mid-April.
- Use a top-quality crabgrass preventer.
- Spread the product with a seed caster or lawn spreader.
- Water crabgrass preventer into the soil.
Once you’ve spread the crabgrass preventer, it’s essential to water your lawn. 1/2 inch of water (about half an hour with a sprinkler) should be enough. This allows the crabgrass preventer to penetrate the soil to the depth of the crabgrass seeds. Once it is watered into the soil, your crabgrass preventer will remain for up to 6 weeks, killing all seeds as they germinate.
Will Grass Seed Be Harmed by Crabgrass Preventer?
Crabgrass preventer will kill grass seed as it sprouts, in the same manner it kills crabgrass seeds. Like all pre-emergent herbicides, crabgrass preventer is non-selective, meaning it attacks any and all seeds upon germination. Grass seed will not survive if it is spread on a lawn where the crabgrass preventer is active.
- Crabgrass preventer will kill grass seeds.
- Do not apply crabgrass preventer if you have seeded your lawn in the past 4 weeks.
- Do not seed your lawn if you have applied crabgrass preventer in the past 6 weeks.
- Seed your Minnesota lawn in the fall for best results.
To avoid conflict between lawn overseeding and crabgrass preventer, create a lawn care calendar that schedules crabgrass preventer for spring and grass seeding in fall. Minnesota grasses perform best when seeded in fall, so it’s entirely possible to prevent crabgrass and seed your lawn in the same year.
What to Do if Crabgrass Preventer Doesn’t Work?
Crabgrass preventer typically remains active for up to 6 weeks, but you may still see some crabgrass appear on your lawn. This may be because of uneven application, heavy rains that wash the herbicide from the soil, or imperfect application timing. The good news is, most of the crabgrass will be stopped by the herbicide, leaving you to deal with only a few stragglers.
Attack crabgrass with a lawn-safe crabgrass killer like Ortho Weed B Gon Plus Crabgrass Control. This product won’t harm turf grasses but will wipe out crabgrass. Alternatively, you can pull crabgrass by hand. It is an annual grass with shallow roots. In small amounts, it can be removed from your yard relatively easily.
When Should Crabgrass Preventer be Applied in Minnesota?
Apply crabgrass preventer to your Minnesota lawn in early to mid-April, when soil temperatures reach 55℉ for 2–3 consecutive days. Remember, the soil temperature is the most important indicator of when crabgrass will begin to sprout, so consult a soil temperature map prior to application.
It’s crucial to apply a crabgrass preventer and water it into the soil just before crabgrass seeds begin to germinate. Once you’ve applied your crabgrass preventer, it will work for up to 6 weeks, killing germinating seeds underground. You’ll know your crabgrass preventer is working if you see little to no crabgrass sprouting in your Minnesota lawn.