Crabgrass prevention without fertilizer

Asked April 10, 2019, 10:57 AM EDT

What, if any, product(s) do you recommend for pre-emergent crabgrass prevention without fertilizer and where can I find it (them)? I live on a lake and want to stop the turfgrass fertilizing to minimize runoff. I am frustrated that the garden stores (Bachman's, Menards, Home Depot) seem only to carry pre-emergent crabgrass preventer with fertilizer. If I am better off to use those products, don't be afraid to say so, but please advise as to why.

Ramsey County Minnesota

1 Response

Thanks for the question. You are to be commended for being concerned about fertilizer run off. It can be a very serious problem. With respect to your primary question, the simple answer is "yes", there are pre-emergent herbicides that do not contain fertilizer. Here are some sites that describe such herbicides:

https://blog-yard-garden-news.extension.umn.edu/2016/04/spring-preemergent-applications-for.html

https://www.doyourownpestcontrol.com/pre-emergent-herbicide-guide.ht

https://homeguides.sfgate.com/ingredients-preen-85568.html

http://www.garden-counselor-lawn-care.com/preemergent.html

Preen is perhaps the pre-emergent herbicide most often used. Its biggest drawback - though this is true for all pre-emergent herbicides - is that grass seeding cannot be done until three or more months have passed since application of the herbicide.

If you want to avoid the use of chemicals in pre-emergent herbicides, corn gluten is often cited as being an effective alternative. However, there does not seem to be consensus on this point. See the following:

https://greenearthagandturf.com/products/organic-weed-killers/gluten-8/

https://www.thespruce.com/corn-gluten-herbicide-careful-timing-2152947

https://www.totallandscapecare.com/business-best-practices/myth-busting-pre-emergent-herbicide/

https://extension.oregonstate.edu/news/corn-gluten-meal-did-not-prevent-weeds-germinating-osu-study

The most important thing to keep in mind is that a pre-emergent herbicide must be applied before crabgrass seeds start to germinate. They will do so once the soil temperature reaches about 55 degrees. The seeds germinate over a period of 5 to 7 days once the soil is at this temperature. Although a snow storm is pending, temperatures over the next few weeks will be in the 50's. Bottom line: now is the time to apply your pre-emergent herbicide.

Good luck!!