I read this brief article in the August issue of Turf Magazine and thought it captured in very few words why crabgrass can be such a problem.  While the article talks specifically about crabgrass in 2013, I think you can read it more generally about problems in any year.  Hope you find it helpful… Mark

 5 Reasons Why Crabgrass is Rampant

from www.turfmagazine.com, 8/5/2013

Kevin Frank, Michigan State University Extension, doesn’t waste words explaining why some of the lawns in your neighborhood may have more than their share of crabgrass.

Here’s the recent post that he and colleague Aaron Hathaway shared on a recent MSU Extension News blog.

I was recently asked by a lawn care operator to reply via email with 1,000 words or less of why it’s an epic crabgrass year – well, maybe he didn’t say epic, but you get the idea. I accepted this challenge heartily, but decided in the spirit of today’s world of texting and twittering to do it in less than 100 words.

1. Record heat and stress in 2012 resulted in bumper crabgrass crop, plenty of seed, and thinned turf for more opportunities for crabgrass to invade this year.

2  Cold, long, spring-delayed crabgrass germination, may have escaped early spring preemergence applications.

3. Soil moisture increases soil biological activity, in turn, increasing herbicide degradation.

4. Plentiful precipitation in June when young crabgrass was geminating helped with root development.

5. High temperatures in July were perfectly timed for crabgrass to really start competing.