Water Requirements

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Pdrizzle
Posts: 25
Joined: June 19th, 2017, 1:06 pm
Location: Northern Utah
Grass Type: Kentucky, Rye, Fescue mix
Lawn Size: Not Specified
Level: Not Specified

Water Requirements

Post by Pdrizzle » April 27th, 2018, 11:38 am

I live in Northern Utah which received very sporadic and infrequent rain in the summer. I've switched my lawn over to an organic feeding and weed prevention program with very pleasing results. The lawn came in twice as thick and green as it had in previous springs.

We are now entering the irrigation part of the year (we've gone two weeks with no measurable rain) and I'm a little confused on the watering guide provided by the state's Slow the Flow campaign. I understand we want infrequent and deep watering to achieve one inch of water per week to keep the grass growing. I have pop up sprinklers only that water at a rate of about .5"/20min. Should I water for 40 minutes to achieve the 1" requirement or should I break that up into two irrigation sessions?

Also, once we get to July we will have heat waves that last about a week and exceed 100 F...should I water more than the 1" per week? Or is that sufficient to beat the heat?

Lawn is a Kentucky Blue grass, rye, fescue mix. Here is a picture of our backyard taken two days ago.
Image

bpgreen
Posts: 3871
Joined: January 3rd, 2009, 2:28 am
Location: Utah (Wasatch Front)
Grass Type: Western, Streambank, Crested wheatgrass in front (with blue grama added in the heckstrips), sheep fescue in back; strawberry clovetr in both
Lawn Size: 3000-5000
Level: Experienced

Re: Water Requirements

Post by bpgreen » April 27th, 2018, 12:08 pm

I looked at the slow the flow website and found a map that said how often watering might be needed in various counties, but didn't see anything that recommended an inch at a time once a week. Where did you find that? I think an inch a week is generally a good approach.

Unless your lawn is starting to show signs of stress, you may want to check the weather forecast and hold off on starting to water. In my zip code, weather.com is showing a 60% chance of rain Mondya

What kind of soil do you have? It seems like there are two extremes in Utah, with nothing in between. Either heavy clay that the water has trouble penetrating, or loose sand that the water runs right through.

I've got the heavy clay, and when I first started trying to water deeply, I think I could only water for about 10-15 minutes before the water would start running off (it takes me longer than you to get 1/2 inch of water, also).

I'd set the irrigation system to run for 10 minutes per zone, then have a half hour to let it soak in, then another 10 minutes, then another half hour to soak in, then another 10 minutes. As time went on, I could extend the amount of time watering, because it was able to soak in more deeply.

I also set the sprinklers to run starting just after midnight, so I lose less to evaporation. Don't worry about any guides that say that watering at night will lead to fungus. It's dry enough here, that the water won't keep the lawn damp enough for that to be a problem (unless you're watering several times a day).

I think I may be putting down an inch at a time now (for the full cycle of three times per zone), but I wasn't getting nearly that much when I first started watering deeply. If you can't get an inch to soak in, then water less than an inch, and water twice a week (if the water is running off, it doesn't do any good to keep watering). After a while, the combination of increasing the organic content of your soil and proper watering should allow you to water more deeply, so you'll be able to get an inch to soak in.

Once it starts getting hot and dry, watering once a week probably won't cut it with a traditional KBG, Rye, Fescue lawn. We lose too much to evaporation.

It's probably still better to water deeply, because the water that soaks in more deeply won't evaporate as fast. I say probably, because I think roots tend to get shallower as it gets hotter, and it doesn't make sense to water past where the roots are. You may want to water a little less deeply. You'll likely need to water more often. I don't think I ever got to the point where I could water KBG once a week all summer, but I think I was able to get by with twice a week. My lawn is now mostly native grass, so I won't start watering for another month or so and will then only water a couple of times all summer.

Pdrizzle
Posts: 25
Joined: June 19th, 2017, 1:06 pm
Location: Northern Utah
Grass Type: Kentucky, Rye, Fescue mix
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Re: Water Requirements

Post by Pdrizzle » April 27th, 2018, 1:53 pm

Sorry, I conflated two sources...the lawn maintenance article on this site said 1", the slow the flow site only listed irrigation increments of .5. 1 irrigation = .5, 2 irrigation = 1, 3 irrigation = 1.5, etc.

Heavy clay...so heavy in fact that my daughter and I dig into the soil, pull out clay, make pots and fire them in the backyard fire pit. They aren't too pretty but they work as clay pots!

Thanks for the tip on the lawn fungus...I was worried about that last year and trying to time it perfectly to the sun rising...glad I can forget that.

Lawn looks good right now, no stress that I can see. I am planning on applying GrubEx to deal with some grubs in the back yard that will require watering. I will test the sprinklers then. My 1/2" per 20 min is only what the sprinklers can produce not what my lawn will soak up. We'll see what the test results are and change accordingly.

Thanks for your wisdom, much appreciated.

bpgreen
Posts: 3871
Joined: January 3rd, 2009, 2:28 am
Location: Utah (Wasatch Front)
Grass Type: Western, Streambank, Crested wheatgrass in front (with blue grama added in the heckstrips), sheep fescue in back; strawberry clovetr in both
Lawn Size: 3000-5000
Level: Experienced

Re: Water Requirements

Post by bpgreen » April 27th, 2018, 2:52 pm

Lawncare in Utah definitely comes with its own challenges.

One mistake that a lot of people make (especially people with secondary water) is to overwater and to water too often. The best approach is to watch for signs of stress (grass starts to turn pale, it doesn't spring up quickly when you walk on it, etc) and water when you see the stress first start to appear. Too many people just set their sprinkler systems up to water every day and never adjust based on the needs of the lawn. I've read that the most common lawn problems here are caused by too much water.

Pdrizzle
Posts: 25
Joined: June 19th, 2017, 1:06 pm
Location: Northern Utah
Grass Type: Kentucky, Rye, Fescue mix
Lawn Size: Not Specified
Level: Not Specified

Re: Water Requirements

Post by Pdrizzle » May 1st, 2018, 1:05 pm

bpgreen...thanks for the tips. I ran the irrigation system late last week to check on absorption and time to generate 1/2" of water. The weakest zone in the system took 25 minutes to generate 1/2", the others were in the 19-20 minute range. In all zones but the Hell Strip the turf absorbed the full 1/2" without running off. The Hell Strip is an absolute mess, the developer planted Maple trees and sod there. The Maples are beautiful but the soil there is hard, weedy, and very difficult to work with. Water ran off after just a few minutes. I noticed on your profile you've got blue gamma planted in your "Heck Strip" (very Utah, made me chuckle :)). How has that worked for you? Would the low water requirements for the grass impact the Maple trees planted there? I want to keep the trees but I feel like the KBG turf there is an absolute energy drain and completely worthless. Any ideas? I'd love to get your feedback.


bpgreen
Posts: 3871
Joined: January 3rd, 2009, 2:28 am
Location: Utah (Wasatch Front)
Grass Type: Western, Streambank, Crested wheatgrass in front (with blue grama added in the heckstrips), sheep fescue in back; strawberry clovetr in both
Lawn Size: 3000-5000
Level: Experienced

Re: Water Requirements

Post by bpgreen » May 1st, 2018, 2:18 pm

I think I called it a heck strip as a joke because I'm in Utah. I've actually planted blue grama throughout the lawn since I last updated my grass types. One drawback to having it mixed in like that is that blue grama thrives in hot dry weather so it grows taller than the rest of the lawn in summer, but there's not enough of it that I feel like mowing the lawn just to get the patches of grama.

I'm not sure how blue grama would do under maple trees. It's a warm season grass and likes a lot of sunshine. The maples may shade it too much. Also, blue grama will stay dormant a lot later than cool season grasses (I've mowed a couple of times already, and the grama is still dormant).

I wonder if a fine fescue would be a better choice. Fine fescue generally doesn't need as much water, light, or fertilizer as KBG. If I remember correctly, it also doesn't have deep roots. Instead, it has shallow roots that fan out, so it gets water from near the surface over a large area (that may be specific to sheep fescue, which isn't a real common turf grass). One potential drawback to fine fescue is that most types of fine fescue are bunch grasses and only spread slowly via tillering (putting up new shoots right next to the existing plant). The exception to that is creeping red fescue, which spreads via rhizomes, but not nearly as well as KBG.

Do you know what type of maples they are? Unless they're a variety that stays small, the hell strip is a horrible place for them. I don't understand why so many people plant big trees in hell strips (especially trees that have lots of big roots near the surface). They look fine at first, but as they grow, their roots spread and push the sidewalk up.

Another thing to watch for is iron chlorosis, which causes the leaves to turn yellow, or yellow with green veins. Some maples (silver maples especially) are not very well adapted to high pH soil, and are susceptible to iron chlorosis.

There are a few ways to treat iron chlorosis. You can spray the leaves with water soluble iron. This will cause an immediate green up, but it's short lived (weeks at the most). It can also discolor sidewalks and driveways. And when the highs get above about 80 degrees, it can cause the leaves to burn. Another option is to water in EDDDHA chelated iron around the drip line. This takes a little longer to take effect, but can keep the leaves green for a longer period of time (I think a month or more). With our soils, you need to make sure it's EDDHA chelated iron, not EDTA. Unfortunately, EDDHA is harder to find and is also generally significantly more expensive. You can also incorporate soil sulfur into the ground around the drip line. You'll want to put it relatively deep in the soil (I use a bulb augur too drill holes several feet deep). Soil sulfur works by turning into sulfurous acid, countering the alkalinity of the soil. It can take more than a month to take effect, but the effects can last for several years. You may find pellets or nails that you can put directly in the trunks of the trees, but I would advise against that for a couple of reasons. I tried it early on and I'm not convinced that it made much of a difference. And drilling holes in the trunk (or pounding nails in) causes stress to the tree.

Pdrizzle
Posts: 25
Joined: June 19th, 2017, 1:06 pm
Location: Northern Utah
Grass Type: Kentucky, Rye, Fescue mix
Lawn Size: Not Specified
Level: Not Specified

Re: Water Requirements

Post by Pdrizzle » May 1st, 2018, 3:57 pm

bpgreen....again thank you for your wisdom and willingness to share. I'm quite certain the sidewalks will be destroyed by the Maples in our neighborhood. The entire development has two maples in front of each home, except where the original maples planted were Silver Maples and the homeowner removed them because of the unsightly yellow leaves (iron chlorosis as you suspected). I'm thinking I'll probably just mulch the turf between the trees and hand water the Maples by hand until I'm emotionally ready to take them down and replace them with something a little more appropriate for the location. Thanks again, I enjoyed reading your responses.

bpgreen
Posts: 3871
Joined: January 3rd, 2009, 2:28 am
Location: Utah (Wasatch Front)
Grass Type: Western, Streambank, Crested wheatgrass in front (with blue grama added in the heckstrips), sheep fescue in back; strawberry clovetr in both
Lawn Size: 3000-5000
Level: Experienced

Re: Water Requirements

Post by bpgreen » May 1st, 2018, 4:58 pm

As an aside, I was outside a little earlier and the recent warm weather has actually caused some of the blue grama to start to come out of dormancy. This is probably the earliest I've seen that happen.

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Dchall_San_Antonio
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Location: San Antonio, Texas
Grass Type: St Augustine
Lawn Size: 5000-10000
Level: Advanced

Re: Water Requirements

Post by Dchall_San_Antonio » May 4th, 2018, 6:16 pm

I'm going to toss out my standard water recommendations and then make some comments for Utah.
Watering: Deep and infrequent is the mantra for watering. This is for all turf grass all over the place. Deep means 1 inch all at one time. Put some cat food or tuna cans around the yard, and time how long it takes your sprinkler(s) to fill all the cans. Memorize that time. That will be the time you water from now on. My hose, sprinkler and water pressure takes 8 full hours to fill the cans. Your time will likely be less. I like gentle watering. As for watering frequency, that depends on the daytime air temperature. With temps in the 90s, deep water once per week. With temps in the 80s, deep water once every 2 weeks. With temps in the 70s, deep water once every 3 weeks. With temps below 70, deep water once a month. Note that you have to keep up with quickly changing temps in the spring and fall. This deep and infrequent schedule works in Phoenix and in Vermont, so it should work for you. The reason for deep and infrequent is to grow deeper, more drought resistant roots and to allow the soil to dry completely at the surface for several days before watering again. If it rains, reset your calendar to account for the rainfall.
While this concept of deep and infrequent watering works around the country, some adjustments need to be made for extreme humidity and extreme aridity. You can start with the temperature guidelines and adjust. Other adjustments need to be made for soil types. If you live in gravel soil that holds no water, then you have to water more frequently. Clay would be different on the other end. In any case, daily watering like you find in Florida and California, is NEVER appropriate. Phoenix is not as arid as it used to be, but I have a friend there who waters his St Augustine 3/4-inch every 3-4 days but only after the temps get above 110 degrees F.

You mentioned grubs. Grubs are usually not a problem until late summer. If you suspect you have grubs, dig up a square foot of turf and count the grubs you find. If you find fewer than a dozen, then the lawn can handle that. If you find an uncountable mass of grubs, then the organic solution is beneficial nematodes. Those things have to be applied to fairly moist soil, so with your aridity, plan for it. My usual suggestion is to apply BN on the 3rd day of a 4-day rainstorm. BN need the moisture to move about. Once it dries, they are stuck.

As for your hell strip, you might mulch it for now and leave it alone for the season. The mulch will improve the moisture content of the soil even without watering it. The improved moisture content will help the soil microbes populate and improve the soil for you. Then in the late summer you could consider seeding some of bpgreen's patented mix of prairie grasses out there. I believe one of his lessons learned was to kill out all the turf grass before planting prairie mixes.

Pdrizzle
Posts: 25
Joined: June 19th, 2017, 1:06 pm
Location: Northern Utah
Grass Type: Kentucky, Rye, Fescue mix
Lawn Size: Not Specified
Level: Not Specified

Re: Water Requirements

Post by Pdrizzle » May 8th, 2018, 2:45 pm

Dchall...

Thanks for the watering tips. Considering the clay soil and aridity I will go for as long as I can without run-off with a 1 inch ceiling as frequent as necessary based on air temperature. Should be about 40 minutes based on my current system and pressure.

Last summer I pulled up a section of grass (about 2 square feet) where I suspected some grub damage and found two grubs. I didn't do anything in the fall expecting the lawn to take of itself. For the most part it did. There are two patches of dead grass about the size of a large dinner plate each that I think are from grub damage last year. I pulled up the dead grass and threw down some seed earlier in the spring.

A few weeks ago I noticed little circles (about 10 in number) of dead grass about the diameter of a baseball spread over a 10 foot by 2 foot section of the yard. I assumed it was additional grub damage but maybe I'm wrong. I pulled up the dead grass and found no grubs. I prepped the soil and planted grass seed.

Curious if you think the damage is something other than grubs.

Thanks as always for sharing your wisdom with a novice like me.

BTW your advice that you offered to me last year regarding fertilizer worked like a charm. Grass was thick and green from the word go this spring. Thanks so much!!

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Dchall_San_Antonio
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Re: Water Requirements

Post by Dchall_San_Antonio » May 17th, 2018, 2:58 pm

Glad I could help. Glad I could help to repeat advice I've received in this very forum.

If you can post a close up picture of the dead grass we might be able to identify a fungal disease. Close means 3 inches away, preferably on a cloudy day or in the shade.

Pdrizzle
Posts: 25
Joined: June 19th, 2017, 1:06 pm
Location: Northern Utah
Grass Type: Kentucky, Rye, Fescue mix
Lawn Size: Not Specified
Level: Not Specified

Re: Water Requirements

Post by Pdrizzle » May 17th, 2018, 6:39 pm

Dchall...I have already pulled up the dead leaves and any root material that came with it, turned the soil a bit added compost from the bin and planted new seed. It doesn't seem to be spreading beyond the original area. I'll take pic of what it looks like now, may not help but maybe it will. If the spots show up anywhere else I will take pictures and post them here. Thank you.

Pdrizzle
Posts: 25
Joined: June 19th, 2017, 1:06 pm
Location: Northern Utah
Grass Type: Kentucky, Rye, Fescue mix
Lawn Size: Not Specified
Level: Not Specified

Re: Water Requirements

Post by Pdrizzle » June 5th, 2018, 2:02 pm

Dchall_San_Antonio wrote:
May 17th, 2018, 2:58 pm
Glad I could help. Glad I could help to repeat advice I've received in this very forum.

If you can post a close up picture of the dead grass we might be able to identify a fungal disease. Close means 3 inches away, preferably on a cloudy day or in the shade.
Just to close the loop on this one, the spots have not returned and the reseeded areas are doing good. Whatever it was the lawn seemed to take care of itself.

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