Xtremehorticulture

Have A Lawn in Las Vegas? I Feel Your Pain.

            If you still have a lawn in the Las Vegas valley, I feel your pain. Lawns seem like they are a dying breed in our valley. But rest assured, they have their place even if you feel a bit slighted. This is a disease problem. You can tell because it is scattered through the lawn and the pattern cannot be tied to the irrigation system directly. It is also possible it could be an insect problem but not likely if it is tall fescue.             Lawns provide a great deal of comfort in a desert landscape. It is the only plant surface that is durable to foot traffic and stays a cool 95F even if temperatures soar to 115F or more. Since our body temperature is normally around 99F, a lawn remains cool to your touch. Asphalt, cement and synthetic grass will hit 160 – 170F in full sunlight on a balmy 105F day. I know. I measured it.             Lawns have their problems particularly this time of year. If you miss an irrigation, have a plugged or broken irrigation head, or a poorly designed or installed irrigation system you will see the results now as brown spots popping up which may die. A lawn in this inhospitable climate without a really good irrigation system is disaster. See how the spots are distributed through the lawn? Disease or insects because it is a random pattern. See how the grass looks healthy around the spots? The disease timing for treatment with a fungicide has passed. Fungicides are preventive, not curative. You have to catch it earlier to use a fungicide.             Then there are diseases and insect problems as well. Those with a tall fescue lawn will see fewer insect problems but there are a couple of serious disease problems that popup this time of year. They usually start appearing in late July or in August, oftentimes when the “summer monsoons” enter the valley from the south.             The biggest culprit for fescue lawns is humidity coupled with high temperatures. The humidity at the lawn level is entirely different from the humidity you feel. As I used to hear Linn Mills say, “Never put your lawn to bed wet.” How true. Never, never irrigate your lawn in the summer with only a few hours to dry out before it gets dark. Irrigate any time after 2 am but before the sun comes up. This is drought. If you look at the centers of the dark green spots you will see sprinkler heads. The sprinkler heads were spaced too far apart or there was inadequate water pressure to give head to head coverage.             Other things that reduce the humidity at the lawn level and reduce disease problems are to avoid thick, dense lawns during the summer months; if you fertilize in the summer use very light applications during the hot months; dethatch your lawn (it thins the lawn and lets humidity escape) in September or October when fewer weeds will try to invade; mow a bit shorter during the heat to let moisture escape.             I will post some pictures of common lawn problems on my blog. Come take a look.

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This Thing in My Lawn and Dwarf Fig

Q. This thing is throughout my lawn and I don’t know what it is. Can you tell by the picture? I also want a dwarf fig and the local nurseries do not carry them. I looked on the web and found several and wondering what one you might recommend. A. The lawn grass picture is not something that I recognize immediately. The first two things that come to mind are the mushrooms that pop up in lawns after some rains and during the cool times of the year and earthworms surfacing and pushing up soil.             It is hard to see it from the picture but the mushrooms make the most sense. These do not look like typical mushrooms since they don’t have the caps that normal mushrooms have and so homeowners immediate response is to say no it’s not a mushroom.             These mushrooms come from decaying organic material in the soil like woody soil amendments were buried or even dying roots from trees and shrubs. Sometimes they look like vomit (sorry for being coarse) on the lawn or wood mulch. They will disappear with the heat and as they exhaust the supply of wood in the soil.             If it is the mushroom then just destroy the mushrooms with a rake turned upside down. If it is earthworms, jump up and down for joy (not on the lawn) and punch some more holes in the lawn with an aerator. I don’t think I was much help on this one.             Blackjack fig is a good one and stays somewhat small and I see it in most nurseries.

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Small Dark Green Circles on Lawn

Q. I have nice green circles on my lawn. Yes, I have three dogs!  The lawn was put in about nine months ago as sod.  It suffered from minor fungus last summer and those areas were resodded about three months ago which you can see in my photo.  About a week ago I added a nitrogen only fertilizer.  Do I need to add something else to the lawn?  I would like the lawn to look green like the circles which I assume are a result of my dogs!  Or is this some other issue? A. Thanks for telling me you have the dogs. You must read my column. Green spots or small circles can be from dogs. If it is from dogs, the spots are usually 6 to 10 inches in diameter with a smaller circle of dead grass in the center. Dog urine damage to lawn. If the lawn had been fertilized with a high nitrogen fertilizer at Thanksgiving the circles would not be as notieable             The concentrated dog urine kills the grass in the center of the green spot due to its concentration but acts like a high nitrogen fertilizer as it becomes more dilute further from the dead grass. The diluted dog urine causes the grass to become greener and grow more rapidly. So the dark green grass surrounding the brown dead center is frequently taller than the surrounding grass.             If it is warm outside, an application of high nitrogen fertilizer plus one or two mowings to remove the brown dead tips of grass should even the color out through your lawn. Nitrogen is the primary fertilizer responsible for having a green lawn. The other is iron. You cannot substitute one for the other. Nitrogen also stimulates growth. Adding more nitrogen means mowing more often.             Your lawn is very dense in the picture. This might also contribute to disease problems. You might try reducing your fertilizer applications to about half of what you are applying now to decrease its density and help improve air movement through the grass. This might help reducing disease potential when it is hot outside.             You could also try mowing your lawn a bit shorter in the summer months, no shorter than 1 1/2 inches. This might also help reduce disease potential. Make sure you are irrigating your lawn in the early morning hours, not at night where the water can sit on the lawn for several hours before it evaporates.             I have a class coming up on lawn care management on Sunday, February 26 at noon at Plant World Nursery.

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Fall Lawn Replacement in the Hot Desert

 Upper surfaces of grass blades can help identify which type of grass it is: L to R, Kentucky bluegrass, perennial ryegrass and tall fescue  Q. I need advice. We planted about 100 square feet of sod a couple of years ago. It had been doing quite well. I believe it was over fertilized 5-6 weeks back.. It is now very brown and not responding to watering. I plan on replacing it with new sod once it cools down. My question is, can I put the new sod over the old or pull out the old and re-prep the sub base? Any advice would be appreciated. Sod removal using a sod cutter A. You didn’t say what kind of sod it is but I am assuming it is tall fescue. Tall fescue represents about 98% of all lawn grasses in the Las Vegas area due to its tolerance, for a cool season grass, to our high summer temperatures. Before you do anything make sure it is dead. Tall fescue can appear dead but if you see any green at all at the base of the dead grass then it may just have died back. Tall fescue is very drought resistant even though it uses a lot of water. It can dieback when water is not available and sit there for quite awhile appearing dead and then re-emerge from grass that looks dead and start growing again. This might take a couple of weeks of applying water after it turned brown. It might then be a bit sparse and you may have to seed into the grass again to get it to fill in those bare areas that didn’t make it. Power rake, aka dethatcher aka verical mower used for removing thatch, slicing stolons and improving water penetration to turfgrass or lawn. However, if it did turn brown due to a heavy fertilizer application then that is salt damage and tall fescue is not all that good in its tolerance to salt and then it is very probable you are right. You have two alternatives in replacing the sod. One is to rent a sod cutter and cut the old sod out leaving behind a ready made surface for resodding. Or you can try digging it out by hand and leveling the surface in preparation for the new sod. A lot of work. You will not be able to put new sod on top of the old sod. The old sod will leave an “interface” that will cause all sorts of problems for the new sod. There is still yet another alternative worth considering. The dead grass is a perfect seedbed for seeding a new lawn. In about late September to mid October mow your dead lawn as short as you can and use your bag on the mower. Don’t mulch the dead grass back into the dead lawn. Next rent a power rake, sometimes called a dethatcher, and dethatch the dead lawn deep enough (you can adjust it) so that when you make a pass or two you can see soil between the dead grass blades. It is important to see bare soil throughout the dead lawn. Patchy look to a lawn when a coarse textured grass is seeded into a finer textured grass. An example would be seeding K31 or Kentucky 31 tall fescue (a pasture grass) into bluegrass or even a turf-type tall fescure with a finer texture Purchase good quality tall fescue grass seed, 100% tall improved tall fescue and not Kentucky or K31 tall fescue, the cheap stuff. Apply a starter fertilizer such as 16-20-0 or any fertilizer high in the middle number(in this case 20) but having some of the first number (in this case 16). Seed at about 10 to 12 lbs of seed per 1000 square feet and topdress it with topdressing or steer manure with NO MORE than about 1/8 inch of topdressing. It is best to do this with a roller for applying this stuff. You can rent one from most rental places. Irrigate about three times a day for a few minutes each cycle. Irrigate long enough to wet the topdressing but not long enough to cause it to run off of slopes or puddle. Do this about 8 am, 1 pm and 6 pm. Your biggest challenge will be keeping the pigeons and other birds off of your seeding. Reduce your watering to once a day when you see grass emerging usually in 7 days or less. A wild idea would be to not use tall fescue but a different grass seed that has high tolerance to heat in our area and a much softer feel to it. These are the heat tolerant perennial ryegrasses. They are superior to tall fescue in feel and water use but you have to get the right kind of perennial ryegrass. Some perennial ryegrasses are very heat tolerant and others are not at all and will burn up when it gets hot in the summer. One of the best of the perennial ryegrasses is a combination of Palmer and Prelude perennial ryegrasses. It has been used on golf courses for nearly 30 years now here and does very well in the heat. You can mow it short as close as ½ inch or less (if you seed at the right rate for this kind of cut) or even up to two inches. It is soft to the touch, unlike tall fescue which has tiny hooks on the edges of the leaf blades that can cause “itchiness” some people think is an allergy which it is not. The problem is that it is only available in 50lb bags. This seed blend is available in Las Vegas from Helena Chemical Company but it will be pricey in that quantity. I could not find it on the internet in smaller quantities.

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