Crabgrass prevention without fertilizer
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
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:
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:
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.