Weak Grass

I'm really having a difficult time of trying to keep my lawn healthy out here, which is quite the opposite of what I expected.

From my lawn experiences in California, I'm used to watering the grass for 15 minutes two or three times a week. I realized that wouldn't cut it here in Minnesota about a month ago. However, it seems that my response has been too little, too late.

Parts of my lawn are doing just fine (mainly the parts I see), but parts are in real trouble (mainly the parts my neighbors see). I don't think it's insects (grubs). I've fertilized the lawn a couple of times since spring, though I haven't used an insect control product, mainly because I don't see any insects or predators (birds) on the lawn. I don't see my neighbors watering any more than I am (of course I water at 3am, so if they're watering at 3am and 6pm, then I'm in trouble).

I think it's just that I'm not watering enough, but that's really baffling me. I'm watering about 30 minutes every other day (I can water my lawn on even days). I made sure that my sprinklers were all running correctly last night (need to buy one new head, but it's not in the affected area), adjusted a few, and increased the run times of a few zones. I'm hoping that with enough water I'll be able to bring my lawn back. Grass is pretty hardy, so I imagine it will be back next spring, but I'd like it back by this August.