When and what pre-emergent did you use?

Pre-emergents are used in the spring before the annual weed you are trying to block has germinated. For crabgrass, the general thought is that it is put down between the time the forsythia blooms and the time the lilacs bloom.

Last year, due to the heat wave in April, the stilt grass germinated earlier than normal. I had some pre-emergent down by that time, but did not get to do the entire area I wanted to do.

I went to Mendham Garden Center and bought a large bag of "contractor's" pre-emergent that did not have fertilizer in it. Where I was able to get it down, it worked well.

I used several things in different areas, corn gluten, standard crabgrass treatment with fertilizer, and the inhibitor that is compatible with lawn seeding.

The standard crabgrass treatment seemed to work better at higher than recommended applications, so I would try to get it without fertilizer next year and spread it higher.

The corn gluten seemed to delay but not stop it - maybe a second application? Again a high concentration was needed.

The lawn seeding compatible treatment just delayed it.

I put it on in mid-April, when the forsythia was in full bloom. One problem is that there was no rain to dissolve the stuff and make a film and watering it in with a sprinkler just wasn't enough. Stilt grass usually germinates in late May, I think. So a second treatment then would help. Preferably shortly before a good rain.