Recent rainfall has provided some relief to the driest parts of Michigan. However, the isolated nature of the rain events has been both a blessing and curse for turf. The blessing is of course some relief from the bone-dry soils that has resulted in unirrigated turfgrass areas going dormant and staying dormant for an extended period of time. For these unirrigated areas that have received rainfall, the turf may start to emerge from dormancy and green shoots may soon be evident.

I have seen several unirrigated turf areas that are not responding to the rain. My best guess is that the turf is not dead, but that the amount of rain hasn’t been sufficient to thoroughly wet the soil and stimulate turfgrass growth. In other areas, the turf does seem to be slowly emerging from dormancy.

If your patch of turf is greening up and resuming growth, it would probably be a good idea to consider a fertilizer application to help the turf recover. I would advise that you wait until full green up before considering any fertilizer application and then make sure to apply a slow release fertilizer that will gradually begin to feed the turf through August and September. Avoid making any fertilizer applications if the temperatures soar back into the 90s or near 100.

The curse of isolated heavy rainfall events is often observed on golf courses where irrigation has been maintained throughout the drought and then a heavy rainfall comes along and adds additional soil moisture, and most often accompanying high humidity levels that can result in enhance disease activity. The resultant, saturated soils in poorly draining areas can quickly lead to anaerobic soil conditions, root loss and, possibly, even turf death. Considering that the hot weather started in March this year, it’s definitely been an extended, stressful growing season for turf across Michigan.

Dr. Frank's work is funded in part by MSU's AgBioResearch.