Xtremehorticulture

Xtremehorticulture of the Desert

Design and Installing Lawn Irrigation Not As Easy As It Looks

Leave a Comment / brown spots, lawns, turfgrass /

Q. We installed a lawn 18 months ago, but it has a difficult time during summer months. I aerate it, fertilize it and I know the drainage is good because the landscaper installed the system to our HOA requirements. I water twice daily, six days a week around 5 AM and 9 PM. There is a decent amount of shade and the yard faces south. Even the heavily shaded areas have problems. What can I do differently? Brown patches in lawns during hot summers will quickly show irrigation weaknesses. Notice these patches are also close to the patio where people walk. This area should probably be core aerified annually due to traffic. A. I looked at your pictures and the lawn looks good in most places except for a few small brown areas. Brown spots during summer months frequently point out weaknesses in the irrigation system. In your case the brown spots are also in front of the patio where there is alot of human traffic. Areas like this should be core aerified annually. Hollow tine aerifier             My first suspicion is the irrigation system and was not installed or maintained properly. Let’s cover the basic “must dos” when installing and maintaining an irrigation system. Water pressure The operating water pressure MUST be within the operating range of the sprinkler nozzles. Frequently this is 15– 30 psi. Some expensive sprinkler heads have built in pressure regulators, but lesser expensive ones may not. If the water pressure is too high, fogging or misting will occur out of the nozzle. If the sprinkler head is “fogging”, then brown spots will occur in weak areas. If pressure is too high, reduce it with a pressure regulator. If water pressure is too low, remove any pressure regulator, change it for the proper one or install a booster pump to increase the water pressure. Head to head coverage Water must be thrown from the nozzle far enough to reach neighboring sprinkler heads. Sprinkler heads must be installed at distances specified by the nozzles. These distances are meaningless if you don’t have the right water pressure. Sprinkler nozzles Sprinkler nozzles specify the operating pressure range, allowable spacing between sprinkler heads and precipitation rate in inches per hour among other things. These nozzles must be matched to each other. If someone maintains the irrigation system and replaces a nozzle with the wrong kind, it will produce brown spots in underwatered, weak areas.             Curved areas and re-curved areas of the lawn are the most difficult to water. There are adjustable nozzles that can be used but it will always be a weak irrigation area subject to brown spots.             Never water early at night like at 9 PM. If your lawn is healthy and it has a good irrigation system, one irrigation per day during summer is all that most lawns need IF the sprinkler system was designed and installed correctly. Irrigation should finish just before dawn. If you must water late in the day, apply water so that the grass leaf blades dry before it gets dark.             Don’t rake or catch the grass clippings when mowing. Most mowers now are “mulching mowers” with a special blade and deck design. Returning the clippings to the lawn substitutes for one fertilizer application each season.

Design and Installing Lawn Irrigation Not As Easy As It Looks Read More »

Turfgrass Dead Spots. Irrigation Problem?

Leave a Comment / brown spots, drought, irrigation, sprinkler problem, watering problem /

Brown spots or dead areas in lawns can be common during summer months. It might be a disease, but then again, it could be something else. There is a sprinkler head in the center of the green spots. The three primary reasons that lawns develop brown spots or dead areas are due to irrigation problems, the development of diseases and insect damage. Irrigation Problems. How many times have I heard, “I know the sprinkler system was installed right. I did it myself.” Just because you did it yourself, does NOT mean it was done correctly. If it was done correctly did you design it for “head to head” coverage? Did you size your pipe taking into account all of your nozzles gpm and friction losses? Did you make sure the pressure of your  First sign of an irrigation problem is that smokey-grey color in your lawn when it gets hot. system falls within the manufacturers recommended pressure range for your nozzles? I can go on. If you understood these terms and took them into account then maybe you did it right. Pressure too high. Sprinkler in the center of that little green spot of grass Any weaknesses in your sprinkler system will show up when temperatures hit 110F and 15% humidity. Lawn water use will exceed 4/10 of an inch of water every day. The first thing you will notice when temperatures start to get hot are smoky-grey patches start to show up in your lawn. Then the brown spots or patches start to appear and they are often not clearly defined. Oftentimes they are smack dab between the irrigation heads when heads are not spaced appropriately, nozzles are mismatched, heads are not perpendicular to the lawn or you use 2 inch popups when you should use 4 inch. Sometimes these brown patches can be right next to the head if the pressure of your system is too high and the sprinklers “fog”. In order to clear up the problem or you use the wrong type of nozzles. Little bit of drought and disease mixed in this lawn. ·       Know the operating pressure of your sprinkler system. ·       If mowing at two inches or above use four inch popup sprinklers. ·       Space sprinkler heads and select the right nozzles to provide head to head coverage (water from one nozzle should reach the neighboring nozzle and vice versa). ·       Size irrigation pipe to provide water flow through the pipe not to exceed 7 feet per second when operating. ·       Use a system pressure regulator (if operating pressure is to high) or a booster pump (if operating pressure is too low) so that operating pressure falls within pressure range recommended by sprinkler nozzle manufacturers.

Turfgrass Dead Spots. Irrigation Problem? Read More »

Brown Spots Probably Disease Problem on Tree Photinia

Leave a Comment / anthracnose, brown spots, photinia leaf spot disease /

Q. Can you tell what the problem is with my patio tree and what I can do about it? The leaves are all covered in brown spots. I am not sure which plant it is. A. From the looks of the plant it seems to me to be a photinia pruned as a patio tree. From the pictures you sent with the black spots on the leaves I think it is either photinia leaf spot disease or more likely, anthracnose. Neither one do we see much here.             Both diseases can attack photinia and Majestic Beauty hawthorne so if your tree is either one of these, this might be the problem. Majestic Beauty is particularly prone to anthracnose while the smaller shrub-type hawthornes usually are not.             Unhealthy plants are MORE likely to get a disease than healthy ones.  Anthracnose usually makes dark brown or tan spots that look like irregular targets with concentric irregular rings in them.             Poor air circulation and wet leaves will make this disease worse. These diseases are thought to spread when leaves are wet or if you spray them with a hose to keep them moist. So irrigate only at the base of the tree and do not spray the leaves.             The tree and the interior of its canopy need air circulation to stay dry. Prune out entire limbs from the trunk or branches so that air can move through the canopy and not stagnate.             Leaf spot disease is caused by a different fungus and can re-attack the tree year after year if you don’t pick up diseased leaves that have dropped and dispose of them.             The disease is less likely to be active when it is hot out. So if you have to spray the foliage then avoid doing it during the cooler months. Do it during the summer in the morning hours.             I noticed something on the bottom of your leaves when I magnified the picture you sent. Aphids? Soap and water sprays on the undersides of the leaves will control them. Do it every three days for about four applications.             Your tree is not in the best of health. Apply iron chelate in the form of EDDHA and a good flowering tree fertilizer now, in very early spring, and once again later in the season.

Brown Spots Probably Disease Problem on Tree Photinia Read More »

Brown Spots in Pear and Apple Flesh Could be Lack of Calcium

4 Comments / Anjou pear, apple flesh, bitter pit, brown spots, calcium sprays, corky spot, Keifer pear, Mutsu apple, pear flesh /

Do you have an apple or pear tree that is about 10 or 12 years old, giving you delicious looking fruit ball when you bite or cut into the fruit, you see corky, brown spots in the flesh? If you do, this could be a sign that your fruit trees will need to be sprayed with calcium when the fruit is young and during its formation. Corky spot in Keiffer pear This disorder is called bitter pit in apple but called corky spot when it occurs in pear. The root of the problem is the same; not enough calcium getting from the soil to the developing fruit. Established fruit trees take a lot of nutrients out of the soil each year for the developing fruit. It would seem unlikely in our desert soils that are full of calcium that a lack of calcium would be a problem. But it can be. Established fruit trees continually mine nutrients from the same areas of the soil each year. Once a tree becomes established where irrigations are limited to a certain area, the root systems do not continue to explore the surrounding soil. They continue to mine these elements where they are. Corky spot in Comice pear Calcium is relatively insoluble. In other words, even though there is plenty of this element in the soil it does not easily dissolve into the applied water before it is taken up by the plant. Producing fruit, and a lot of it, draws heavily on the supply of calcium the tree can find in the soil. Over years the available calcium supply diminishes. If the soil does not allow calcium to dissolve when the plant needs it, calcium deficiencies occur. If you look closely at the fruit there can be telltale indicators that bitter pit or corky spot is present without cutting into the fruit. I look for dimples in the skin. If you look closely at these dimples you will see that they do not “ripen” or turn from green to its mature color like the rest of the skin. If you don’t look closely, you will miss it. Greenish dimples on the surface of the fruit can be a dead giveaway that corky spot or bitter pit has affected the fruit. Cutting the dimple away will expose the corky spot just under the surface. Normally this calcium deficiency occurs on some apples and some pairs but it is less likely on others. In our climate in the Las Vegas Valley I have seen it develop on Mutsu apple and Anjou, Comice and Keiffer pears. To remedy the problem you will need to spray on the fruit as it is developing, calcium sprays. I usually buy food-grade or aquarium-grade calcium chloride. I dissolve about 3-5 pounds of calcium chloride in 100 gallons of water. To convert, there is 16 ounces or 454 grams in one pound. Dissolve the calcium chloride thoroughly in warm water and add a liquid detergent or some sort of spreading agent to help the calcium entry through the skin of the fruit. Spray on the fruit as soon as you see the fruit beginning to develop. Make five applications of the spray about one week apart. Avoid spraying when temperatures are high. Spray in the early morning hours. Real wedding the fruit lightly with pure water after the spray has dried will help more of the calcium to enter the fruit. These five applications of calcium chloride applied along with a sticker/spreader when the fruit is still young will help to prevent bitter pit or corky spot from developing.

Brown Spots in Pear and Apple Flesh Could be Lack of Calcium Read More »

What Do I Do? My Lawn Has Dead Spots in Summer

Leave a Comment / brown spots, disease, insects, lawn, turfgrass /

This lawn is starting to recover. Just the dead spots remain. Wait until mid September or even October before you begin to remove dead grass. Leave it there for mulch to prevent weeds like bermudagrass from getting started. If you had dead areas develop in your lawn and you are pretty convinced the damage has passed then it is time to wait until fall to repair it. Three types of problems lead to dead spots in the lawn: insects, diseases and irrigation problems. It is pretty easy to determine if the problem has passed. If it has passed, the grass surrounding the damaged area and throughout the rest of the lawn area will appear healthy and rapidly growing. All that will remain of the damage are the brown spots surrounded by healthy, vibrant, green grass. Whatever you do, DON’T rake up the dead grass now and reseed or resod. Dead spots in a lawn are ugly. But what can be worse if you are not careful is to open up your lawn to a weed invasion, particularly bermudagrass, if you try to clean up these dead spots now. Wait. Wait until Fall, around mid September to mid October, to rake it up and reseed or resod. If you try to reseed it now you will fail. Even laying sod right now will be difficult to keep alive. But if you rake up that dead area and expose the bare soil to sunshine and irrigation, bermudagrass WILL seed itself right into those spots. And then you WILL have a problem. Leave the dead grass alone and let it “mulch” or cover the dead area, protecting it from invasion by bermudagrass.

What Do I Do? My Lawn Has Dead Spots in Summer Read More »

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

Leave a Comment / brown spots, disease of lawn, dying lawn, turfgrass /

            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.

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

Summer Lawn Disease on Tall Fescue Right Around the Corner

Leave a Comment / brown spots, dead Joshua tree, disease, dying lawn, fusarium blight, necrotic ring spot, summer blight, tall fescue /

Starting usually in late June and through the hottest months of July and August, tall fescue can experience the development of brown spots that can rapidly expand from six inches to more than a foot across. Summer patch, once known as Fusarium blight or Frog-eye, is caused by the fungus Magnaporthe poae. Symptoms start to appear when warm summer weather begins. Brown patches emerge during the heat of the summer, often in conjunction with summer rains and higher humidity. In southern Nevada, outbreaks vary from lawns that are highly maintained to those that are poorly maintained. Symptoms are more pronounced on highly maintained turfgrass. Infested sites seem to be prone to environmental stresses that arise from heavy thatch accumulation, mowing turfgrass too low, high nitrogen fertilizer schedules, light and frequent watering schedules, compacted soils and poor drainage. The disease can be spread by maintenance equipment and infected plant material. Even though drought seems to encourage its development, it is frequently found in wet locations. Obviously any type of management that reduces turfgrass stress during the hot summer months will help to curtail development of this disease. Appropriate fertilizer applications, aeration, removal of thatch, deep watering, and mowing higher will go a long way in preventing this disease from occurring. Chemical treatment is an option for summer patch control but the key is to start early. Appropriate systemic fungicides should be applied beginning when night temperatures remain above 70° F. Using the wrong fungicide or high nitrogen fertilizers may actually aggravate the problem. Symptoms The disease organism survives from one season to the next on diseased roots and stems from the previous year. The development of summer patch is highly dependent on the right environmental conditions. Elevated soil temperatures (75o to 85o F) and high soil moisture provide an environment where the disease is more virulent. Disease starts as scattered light green patches 1 to 5 inches in diameter as pathogens attack the roots and crowns of susceptible plants. In the early stages, young roots may appear healthy, although dark brown hyphae may be present on these tissues when seen under magnification. Vascular discoloration and cortical rot occur as the disease progresses. Damage to roots, crown and stem by the disease restrict water uptake and plants begin to appear drought stressed. By midsummer, plants with increasing levels of infection die due to heat and drought stress resulting from their damaged roots and stems. At this stage, roots and stems of plants showing dieback have a dark brown rot. Circular or crescent shaped patches of dead and dying plants are formed by the spread of the pathogen, root to root, from an initial infection site. Several of these patches can coalesce into a patchwork of dead grass in a serpentine pattern, scattered with clumps of healthy grass.  Patches of dying plants create doughnut shaped depressions that can grow to two feet across and turn dull tan to reddish brown and give the affected area a pockmarked look. In some cases, an apparently healthy green patch of grass will be completely surrounded by a ring of dead grass creating a “frog-eye” appearance. In advanced stages where large patches may appear entirely dead tufts of green grass frequently remain in the dead grass, remnants of the earlier “frog-eye”. Since the pathogen survives in infected root and crown tissues, the disease is likely to reappear next year in the same areas with increasing intensity. New patches may be formed after the transport of contaminated roots or root debris from turf maintenance equipment such as power rakes, vertical mowers and aerators. Preventive Management. To minimize the risk of summer patch, it’s helpful to minimize stress on the lawn. Primary stresses include excess thatch, inappropriate fertilizer or incorrect timing of fertilizer applications, high temperatures, low mowing heights, and soil pH extremes. Always apply a balanced N-P-K fertilizer and don’t apply any fertilizer during the June-August stress period. Fertilizers should be applied at half rates as needed. You don’t want the turfgrass underfertilized or overfertilized which may add to stress or increase susceptibility. Avoid heavy early spring and summer applications of fertilizer high in nitrogen. Develop a fall fertilization program supplemented with a half rate summer fertilization program. Deep water prior to summer heat to encourage deeper root systems. Seed heat tolerant perennial ryegrasses such as Palmer, Prelude and Brightstar. Syringe (short applications of water) during the heat of midday during July and August. Core aerate in early fall or mid spring. Remove thatch by aeration, vertical mowing or power raking. Increase mowing height to 3 inches during the hot summer months. Susceptibility to this disease increases as mowing height decreases. Overseed with improved cultivars. When summer patch is severe or when fungicides are not an option then the only remedy is fall overseeding or resodding after the disease has subsided. At this time there are no tall fescue cultivars that have been identified as resistant to summer patch. Treatment with Chemicals. Fungicides may be required for control if summer patch has been a problem in previous years. Apply treatment 3 to 4 weeks before symptoms are likely to occur in late spring when temperatures are in the 65° to 68°F range. Systemic fungicides such as Rubigan, Banner or Bayleton should be applied when night temperatures don’t fall below 70 F. Irrigate after application. Apply fungicide starting in June occur in late spring when temperatures are in the 65° to 68°F range. Systemic fungicides such as Rubigan, Banner or Bayleton should be applied when night temperatures don’t fall below 70 F. Irrigate after application. Apply fungicide starting in June. If this is too difficult, look for a product that says it controls Fusarium blight or summer patch and follow the directions for application precisely. The label is the best source of information. It is NOT a bunch of bologna. They want it to work so you will buy it again and recommend it to others. Remember, nearly all fungicides are PREVENTIVES, not curatives. Fungicides normally protect the

Summer Lawn Disease on Tall Fescue Right Around the Corner Read More »