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How do I know if its fungus, grubs, soil, or water problem? (pic)

Posted by tweedbunny 8a (My Page) on
Mon, Sep 3, 07 at 16:28

I try all summer to save the lawn but it turns yellowish and dies.

Type of grass? I have no idea, its the sharp edged playground grass that feels smooth when you run your finger from tip to root and feels like sandpaper when you run your finger from root to tip.

We water 3 times a week during the heat of the summer, 2 times a night, 20 minutes each. The soil is quite clayish. It's HOT here in summer, consistant temps over 105 from end of June to end of August. Many days in July are over 110.

HOW can I find out WHAT I'm doing wrong? I'm willing to change anything I'm doing but I don't know how to begin finding that out.

I have some people tell me I need to water more often because the roots are shallow from the clay soil. I have others tell me I need to water less frequently to train the roots to grow deeper.

Here's a pic of the two WORST spots although much of the lawn needs help.

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Image and video hosting by TinyPic

Follow-Up Postings:

RE: How do I know if its fungus, grubs, soil, or water problem? (

Your best bet is probably to get a soil test and start there. See what kind of shape the soil is in. Since it appears you have problem areas, I would test those areas independent of the rest of the lawn so that if it a localized problem, the rest of the yard won't dilute the problem.

I don't think watering could cause that big of a problem relative to the rest of the lawn.

Grubs - pull up some of the grass and check the root around for the bugs. If you can't see em, it isn't a problem.

RE: How do I know if its fungus, grubs, soil, or water problem? (

I agree with the soil test. But also you should not water at night. This breeds fungus especially in hot summer months. If you don't want to do a soil test you can put down some corn meal or cracked corn approx 10 lbs per 1000 ft. This should take care of any fungal problems in approx 3 weeks.

RE: How do I know if its fungus, grubs, soil, or water problem? (

As for watering, you need to do the tuna can test. Its the only way to show you how much water your actually applying per zone/time. Read the link below.

You want to shoot for 3/4-1" per week.

Here is a link that might be useful: How to Calibrate Your Sprinkler System

RE: How do I know if its fungus, grubs, soil, or water problem? (

I'm interested in this one. It looks to me like watering was the obvious problem. I wish you had mentioned where you live, but if your temps are over 105 from June through Aug, that pretty much narrows it down to a band from Las Vegas south through Indio to Calexico and east to New Mexico. I grew up in temps like that (before the SoCal smog cooled things off).

Your problem area is on a slope. Slopes, hills, and mounds drain water fast. With your low humidity, high temp, and on a slope; your grass is not getting enough water. The only way to really keep moisture on that would be with a soaker hose running continuously at a trickle. Rather than do that, I would let the grass die out and do something else.

It also looks like you have the wrong grass for your zone. It looks like fescue in the pictures. It should be bermuda if you absolutely have to have a grass. At this point I would plant xeriscape plants on the slope. I don't think you can water it enough under your conditions. If you don't want xeriscape plants, then you could mulch heavily in there and plant pretty much whatever you want that is adapted to your area. Keep the mulch on, though.

When people come here and report a "clay" soil, they usually have clay but without a healthy population of microbes, especially fungi. The people with healthy soil don't usually report having clay. The fungi will help your soil retain moisture, but you have to have moisture for the fungi to survive. That's where the mulch comes in.

As for the rest of the lawn (not on slopes), you should water deeply and infrequently. In your case, twice a week is probably infrequently but three times is pushing the limit. The idea is for the surface of the soil to dry out between waterings so weed seeds will not germinate. No problem with twice a week in your area. As for duration, 20 minutes is not nearly long enough. I water from 1-3 hours per zone. Last night I watered 6 hours because I've been away for 3 weeks and my wife doesn't water that long. Once you have a healthy population of microbes, your soil will not allow runoff, so even with 6 hours, it all soaked in. As for your yard, unless your sprinkler pours out the water, I would start moving up toward 1 hour (from 20 minutes). Watch your grass for signs of wilting. If it wilts, water immediately but water more heavily (longer) until you can go from one watering to the next without wilting. With a clay base, once you get the microbes going, you might be able to stretch it out to once a week watering, even with your heat.

Watering at night is probably not a problem in your area. Our water restrictions in San Antonio require night time watering year round. I've been doing it for a couple years and have not had any more problems than when I watered in the day - and I was expecting problems. Then again I'm on an 100% organic program and fungus diseases are not much of a problem, so your mileage may vary.

RE: How do I know if its fungus, grubs, soil, or water problem? (

I agree it looks like you have the wrong grass type for your climate. No cool season grass like fescue, rye of KBG can take that amount of heat for that long. Only Bermuda can take that with minimal water.

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