Red thread is a fungal infection. It's dominant during cooler seasons and damper ones, but that doesn't mean it can't run rampant in summer!

While recovery tends to happen in fall--it being on the drier side and grass growth increasing again from summer--if the infection is spreading faster than the grass can overgrow it, it'll look terrible.

>>i would hope it's not caused by a lack of nitrogen.

It isn't, per se, although a lack of nitrogen will tend to slow lawn growth and make the red thread much more obvious.

>>I even have an irrigation system and they do not.

How often are you using it? With red thread, less water is better (but it's difficult to cut back immediately). Optimally, lawns do best with 1 inch of water delivered all at once, once per week.

If you're on daily watering, cut back instantly to once every other day. In another ten days, go to every third day. And so on until season's end. Next year, pick up at every third day if it doesn't rain, and slowly pull that back. Eventually you'll hit seven days.

Can a lawn look good at that watering level? Mine's been watered four times this season. The rest of it, nature has done for me--sometimes with 14 days or more between rainfalls. The grass does fine, if a bit wilty by day 15 or so.

>>Other DIY neighbors using a program like Scott's have much nicer looking and greener lawns than mine.

This is because...drumroll please...lawn services stink. On average, there are a few exceptions, but most of the big name lawn services don't deliver very much for their cost.

For a much better lawn, fire them. Then go to your local big box store and pick up either Scott's fertilizer (which I do not like), Vigoro (works for me), or Milorganite (the best of the bunch). Get enough to feed your lawn twice.

Feed immediately at half the bag rate. Feed again in a month at full bag rate.

If you used Milorganite or your lawn didn't stop growing until November 10th or so, feed one last time with Vigoro or--if you must--Scott's at bag rate. Milorganite won't work very well at this point, it's getting too cold and Milo requires bacterial action.

Hi morph,
Please read my additional post on "How to switch over to organic lawn care program.

thanks,
claga