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questions
DISESE
>> What are cinch bugs, and how do I get rid of them?
>> What are grubs, and how do I get rid of them?
>> Why does my grass develop yellow patches after I mow?
>> Why do grass patches turn yellow and die shortly after fertilizing?
>> After the snow melted, pale yellow patches trimmed in pink appeared in my lawn. What's the problem?
>> Why are circular straw-brown spots roughly 8-to-10 inches wide appearing in my lawn?
>> My yard has large, circular patches of brown grass. The leaves first appear water-soaked, but dry and turn dark brown. What should I do?
>> Why is my grass turning gray?
>> Why is my grass pale green in color and growing more slowly than usual?
>> My lawn has turned a bluish-green color and footprints make a lasting imprint. What's the problem?
>> Why does my grass look like it's been dusted with flour?
>> Why is my grass thinning out?
>> Why does my grass become thin and develop bare spots in heavily traveled areas?
>> A number of circular patches are forming in my yard. The centers remain green, but the edges are dying. What should I do?
lawn mowing
>> What should I do with all my grass clippings?
>> How low should I mow my grass?
>> Can I cut off too much grass in a single mowing?
>> Can I leave grass too tall?
>> How often should I mow my lawn?
>> What happens if I mow the lawn too often?
>> Do I need to mow my grass as often in the spring as in the fall?
>> Does it matter what time of day I mow the lawn?
>> Does it matter what pattern I use to mow my yard?
thatch
>> Why does thatch harm my grass?
>> How can I remove my thatch?
>> When should I de-thatch my lawn?
>> How often should I remove thatch?
Fertilizer
>> Why should I fertilize my lawn?
>> What kind of fertilizer should I use?
>> How do I read a fertilizer label?
>> When should I apply my fertilizer?
>> Why shouldn't I fertilize my grass in the spring?
>> When is the best time of day to apply fertilizer?
>> How much fertilizer should I apply?
>> What happens if I under-fertilize my lawn?
Answers
Improper mowing is probably the cause. You're probably removing too much of the grass leaf at each mowing.
You should either mow more frequently so you never remove more than one
third of the leaf blade, or you need to level out your yard's high spots because
the mower is cutting too low as it goes over bumps.
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- Q: My grass blades are turning yellow between the veins, but the veins themselves are remaining green. Why?
You're looking a common lawn problem: iron deficiency. Usually, you'll find this condition in soils with high pH. That' s because in acidic conditions, iron tends to form compounds that plants can' t use. If high pH isn' t the problem, your iron deficiency may be caused by excess phosphorus, a poor root system, over-watering or use of water that has high levels of bicarbonate salts.
You should spray the lawn with a liquid iron supplement. If acidic soil is the root of your problem, drop the pH by adding ferrous sulfate or ferrous ammonium sulfate.
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If the grass bordering these yellow areas is a healthy green color and the yellow areas don' t spread, fertilizer burn is to blame. Whenever excessive amounts of these materials contact grass, they cause the blades to dry out and die.
You can prevent burn by picking up spilled fertilizer, applying fertilizer according to label directions and thoroughly watering the grass after fertilizing to wash it into the soil.
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- Q: After the snow melted, pale yellow patches trimmed in pink appeared in my lawn. What' s the problem?
You' re probably looking at Fusarium patch (pink snow mold). Generally a problem in late winter or early spring, this grass disease usually attacks lawns wet from snow, rain or poor drainage.
Grass blades are usually light tan and stick together, and a white cottony growth may cover the blades. By the time you observe Fusarium patch in the spring, it' s usually too late to apply a fungicide. That' s why proper lawn management is so important.
To reduce the danger of this disease, keep your yard mowed and aerated in the fall, and avoid excess fall nitrogen applications. Frequent mowing can help control the problem too.
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If you' ve had dogs in the area, you' re probably seeing dog urine injury. To correct the problem, water the affected areas thoroughly to wash away the urine. While this won' t completely eradicate the brown discoloration, surrounding grass will eventually fill the affected spots.
To prevent further problems, try to keep dogs off the lawn. If canines can' t be blamed, you may have dollar spot or Fusarium blight.
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- Q: My yard has large, circular patches of brown grass. The leaves first appear water-soaked, but dry and turn dark brown. What should I do?
If you live in a warm, humid area, you may have brown patch. This fungus attacks lush, tender growth, so you' ll usually find it in yards with excessive nitrogen. Often only the blades are affected and the grass will recover. However, severe infections can kill your grass.
To stop brown patch, you' ll need a fungicide with chlorothalonil and at least three treatments spaced seven-to-10 days apart. To prevent it, avoid heavy doses of nitrogen fertilizer, keep your thatch under control and aerate your yard regularly.
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If your grass blades are covered in an orange powder, and the reddish-brown lesions underneath don't rub off, you've got rust. The fungi to blame are usually active during humid weather. Grasses under stress from nitrogen deficiencies, moisture shortages or close mowing are most susceptible.
Rust develops slowly, so in many cases frequent mowing's, adequate water and an application of a high-nitrogen fertilizer can stop the problem. Frequent mowing can help control the problem too.
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If the tips of your blades are pale yellow or gray, perhaps with red or yellow margins, and you see tiny black dots, you can bet its septoria leaf spot. Also known as tip burn, this fungus can infect most northern grass species. The combination of cool, wet weather and unfertilized lawns usually bring on the disease.
A fungicide with mancozeb will control the problem, but you may need three or more treatments. Frequent mowing can help control the problem too.
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Odds are that a nitrogen deficiency is to blame. You'll need to apply a lawn fertilizer to boost soil nitrogen levels.
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- Q: My lawn has turned a bluish-green color and footprints make a lasting imprint. What's the problem?
If the grass recovers during the evening, but darkens and wilts under the daytime heat, your lawn is under drought stress. You'll notice drought damage first along sidewalks and driveways (the hottest and driest areas of the lawn).
Water your lawn immediately.
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Powdery mildew is probably to blame. This fungus-caused disease makes white or gray mold appear on grass blades. As the disease progresses, leaves turn yellow, wither and die. Slow (or non-existent) air circulation, shade and high humidity contribute to the problem.
Chemical controls are available, but your best bet is prevention. I suggest you plant shade-tolerant grass varieties, follow nitrogen fertilization guidelines and selectively prune shrubs to increase air circulation.
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More often that not, thinning grass is a sign of heavy thatch. If your thatch layer is thicker than ½ inch then it's probably slowing grass growth by restricting the movement of water, air and nutrients in the soil.
Remove thatch from your lawn. To get your lawn off to a healthy start by removing thatch build up.
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Compacted soil is the culprit. Aerate heavily trafficked areas annually.
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- Q: A number of circular patches are forming in my yard. The centers remain green, but the edges are dying. What should I do?
This tell-tale "frog-eye" pattern is caused by several fungi. Called Fusarium blight, this is generally only a problem from June through August. Two of the most susceptible grass varieties are bentgrass and Kentucky bluegrass. Lawns are particularly susceptible to the disease when they are under stress from drought. Once these fungi go to work in your yard, you may have trouble stopping them.
Your best bet may be to re-seed with resistant grass varieties. Even then, I'd suggest treating the whole lawn with a fungicide c03/01/2008rol is difficult to achieve.
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Most of the time, the best thing to do with grass clippings is simply leave them alone. Grass clippings less than one inch in length filter down to the soil surface and decompose quickly while forming a nutrient-rich mulch.
It's the longer clippings that tend to remain above the lawn, giving your yard an unsightly appearance and smothering the grass beneath. These clippings should be removed.
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Optimum grass height varies by region - and by grass type. For example, creeping bentgrass spreads by stolons and should be mown below a 1/2 inch. In fact, if you mow this grass variety too high, it may develop thatch problems. Conversely, Canada bluegrass won't tolerate close cuttings and needs to be kept above 2-1/2 inches in order to survive.
Here are some general mowing guidelines for many of today's most popular grass varieties: Recommended Mowing Heights
Grass Cool Months | Warm Months | Final Mowing
Cool Season Canada bluegrass 3 in. - 4 in. - 3 in.
Kentucky bluegrass 2-1/2 - 3 - 2
Annual bluegrass 1/2 - 1 - 1/2
Tall fescue 2-1/2 - 4 - 2
Fine fescue 1-1/2 - 2-1/2 - 1
Annual ryegrass 2 - 2-1/2 - 2
Perennial ryegrass 1-1/2 - 2-1/2 - 1
Velvet bentgrass 1/4 - 1/2 - 1/4
Warm Season St. Augustine grass 2 - 3 - 1-1/2
Bahiagrass 2 - 3 - 1-1/2
Centipedegrass 1 - 2 - 1
Buffalograss 1-1/2 - 2-1/2 - 1
Bermudagrass 1/2 - 1 - 1/2
Zoysia grass 1/2 - 1 - 1/2
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Yes! Never remove more than a third of your grass height at one time. Cutting your grass too short can severely limit its ability to manufacture food and resist weed invasions.
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Yes! Grass that's too tall can promote thatch build-up, encouraging insect and disease damage. For best results, keep your lawn mowed to its optimum height.
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Mow frequently enough that only a small portion of the green leaf is lost at any one clipping - ideally 1' a week so that no more than one-third of the leaf blade should be removed.
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Cutting a lawn too often, particularly with the blade set low, exposes the lower portion of grass leaves to bright sun, burning them. If this happens repeatedly, grass reacts by developing shallow roots. Shallow-rooted lawns are particularly prone to disease and weed problems. In addition, poor rooting does not provide enough nutrients to the grass leaves. A lawn with shallow roots may eventually die out.
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No. Mowing frequency varies by the season. In the spring, established lawns should be mown as soon as the grass greens and begins to grow.
In the summer, close mowing (especially during hot weather) can weaken some grass varieties. As autumn approaches, cool-season grasses begin to grow faster and produce more clippings. Conversely, warm-season grasses begin to slow down. Adjust your mowing habits accordingly.
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I believe that early evening is the best time to mow. The late start gives grass blades time to recover before they're exposed to daytime heat and wind. Mow with a razor sharp blade, and never mow wet grass.
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Surprisingly, yes. It's actually best to mow your lawn in different directions. That keeps grass from developing permanent ridges, ruts or becoming compacted from constant traffic. Be sure that your clippings are thrown toward un mown grass when using a rotary mower as they'll be chopped and pulverized better.
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Thatch appears right at the soil surface and looks like a layer of straw. It's composed mainly grass parts that live underground, but also includes lawn clippings and other un decayed material. In healthy soil, the plant parts decompose quickly into humus, but in soil that is compacted, over-watered, over fertilized or under populated with earthworms and soil insects, you end up with thatch.
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Thatch causes a number of problems for your grass. Thick thatch layers contribute to drought stress because water has a hard time reaching the soil and runs off instead of sinking in. Numerous insect pests live and breed in the thatch layer. In humid climates, thatch harbors fungal diseases. Light can't easily penetrate thatch, making grass spindly. The bottom line: a thick thatch layer is a sign of a sick lawn.
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You'll need a mower that has a de thatching attachment. The large quantity of organic material brought to the surface from using a de thatcher should be removed from the lawn.
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The best time to de-thatch is just before a lawn has its most vigorous growth of the season. That means de-thatch warm-season grasses at the beginning of warm weather in late spring. Conversely, the prime time for de-thatching cool-season grasses is late spring or early fall.
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The actual frequency depends on the type of grass. The best way to determine if your lawn needs to be de-thatch is to closely examine it. If your lawn has more than 1/2 inch of thatch, you should consider removing it.
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When properly fertilized, a lawn maintains good color, density and vigor and it does not easily succumb to insects, weeds and diseases.
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Your lawn will have the best overall health and vigor if it's given a complete fertilizer (containing nitrogen, phosphorus and potassium) at least twice a year. Additional iron, applied if needed, helps give the lawn a dark green color.
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The label on fertilizer bags lists the percentages of the three primary nutrients (nitrogen, phosphorus and potassium) as a series of three numbers called the fertilizer grade. A common lawn fertilizer grade is 23-3-6. In this case, the fertilizer contains 23 percent nitrogen, 3 percent phosphorus and 6 percent potassium.
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Contrary to popular beliefs, most lawn fertilizer should be applied in late summer and fall. By fertilizing in the fall rather than spring, your lawn stays green longer in the fall, greens-up earlier in the spring, maintains higher energy reserves in the summer, and perhaps most importantly, increases its tolerance to summer stresses such as disease.
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Early spring applications of nitrogen cause a surge of top growth. I'll grant you, that makes the lawn look nice in the spring, but it depletes the plant's energy reserves. Consequently, when summer stress periods occur, plants are weaker and less able to survive. It is recommended to apply fertilizer in late October or early November, when top growth is minimal but soil temperatures are still warm enough for nitrogen absorption. With this fertilizer schedule, plants resume growth and green up early the following spring without the excessive shoot growth associated with early spring nitrogen applications.
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If it's liquid, from sun up to 11:00 a.m. If it's dry, wait until the dew is gone (but before 11:00 a.m.) and be sure to water it.
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Fertilizer recommendations are usually based on the amount needed to meet your yard's nitrogen requirements. To determine the amount of fertilizer required to apply one pound of nitrogen to 1,000 square feet, divide 100 by the percent of nitrogen in the fertilizer. Here are some nitrogen guidelines for specific grass species.
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The lawn is not only less attractive, but it's also much more susceptible to environmental stress such as drought.
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