Lawn Care Part 2 - Maintenance and Diseases
May 28, 2020
Last week we talked primarily about getting a lawn started and annual fertilizing. I had wanted to write the article on maintenance and diseases, but the topic, once again, got away from me and took on a life of it's own. So this week I'll do my best to stay on topic. The one thing I forgot to mention last week about fertilizing is that you should only fertilize in the spring and only once with a high Nitrogen fertilizer. If you use Nitrogen fertilizer later in the year it could slow down the lawn's move into dormancy because it will think it should still be growing. If it isn't dormant when the cold weather strikes, you have set yourself up for severe winter kill. Never a good thing. Any fertilizer used in the fall needs to be low Nitrogen and high Phosphorus and high Potassium to strengthen the roots and cells without promoting leaf growth.
Now back to topic. After your lawn is established, it's time to go into maintenance mode. Mowing height is more important than it would seem, especially for new lawns. About 2 ½" to 3" is a good lawn height. Four inches is even better. Any less than that decreases drought and heat tolerance and increases the lawn's susceptibility to insect damage, sunburned roots and, ultimately, weeds. Cutting grass too short will eventually damage your lawn. If you can attach a mulching blade to your mower, you'll direct the clippings back into the ground to improve the soil. Learn what the watering needs are of the grasses that you selected and follow that schedule with adjustments for the weather. You can continue to use the touch test. It works. If you have a soil with a higher clay content use a product such as Revive to break the surface tension of the soil so the water will penetrate deeper and faster.
Enjoy dandelions and don't try to get rid of them. To begin with, it's a losing battle. Dandelions will always be with us. It's a native plant and the seeds travel a long distance. They're the first food of the spring for our pollinators and gets them off to a good start for a productive season of pollinating our vegetables and flowers. Remember, no pollinators, no food. Not only are dandelions good for pollinators, but they're great for good soil management. They have deep roots and break up compacted soil so water and fertilizer can penetrate better. Growing dandelions is actually good for the environment and your lawn.
Water is the most critical aspect of lawn maintenance. And lawns take a lot of it to stay green and healthy. When you water, apply the water slowly so it soaks in to a depth of about 12 inches below the surface. That sounds like a lot of water, but it helps the roots stay deep so they don't dry out and you'll water less often. If the water is running off the soil, you're watering too fast. Sometimes you have to stop the water and let it soak in, then come back and start over. Remember, more water equals more growth and more growth equals more frequent mowing. Be conscious of the variety of grass you plant since it will determine the water requirement.
If you have a Kentucky Bluegrass lawn, or some of the finer fescues, you will need to de-thatch your lawn. Thatch builds up with these grasses and will inhibit water and nutrients from reaching the roots. A de-thatching blade on your mower will take care of the buildup. Or you can LIGHTLY power rake. De-thatching and power raking can be damaging to the lawn so you need to be careful. Core aerating is a better method and can remove up to 10 percent of the thatch. Leave the cores on the lawn to deteriorate and replenish nutrients. Thatch isn't an issue with the native varieties.
Lawns are subject to a variety of diseases, mostly caused by a fungus. Good lawn management can alleviate most problems, but occasionally a lawn will have a disease problem. Summer Patch and Necrotic Ring Spot are two that can be easily prevented by good lawn care. Both start out as circular patches of dead or dying grass. Summer Patch is smaller circles that begin as slow-growing, thin turf that will grow together into larger patches of straw colored grass as hot weather sets in. Necrotic Ring Spot starts as larger areas of dead grass that can be several inches to several feet in diameter. Soil compaction, heat, drought, and poor watering practices cause both. Thatch plays a big role in Necrotic Ring Spot. The good news is that they are preventable. Although you'll probably have to reseed the dead areas, alleviating the stress on the grass with regular, deep waterings, fertilizing with a good Phosphorus and Potassium fertilizer, and aeration will help turn these problems around.
Fairy Rings are most often seen in areas where the soil stays more cool and moist. They appear as rings of dark green grass, sometimes with dead spots. Occasionally, mushrooms will grow in the ring. Hence the name, Fairy Ring. They are usually small, but can be large. To alleviate Fairy Rings, open up the soil mechanically. That means aerate. If it's a very small area, you can aerate with a soil probe or other similar device that will remove plugs. If they're larger, you may need to rent an aerator. Then soak the spot with water for a month and fertilize with the appropriate fertilizer for the season. Fairy Rings aren't damaging to the lawn, but they do indicate a problem in the location of the rings.
Ascochyta Leaf Blight appears as straw colored turf with the tips of the leaves dying back. It's caused by winter drought (relieved by winter watering) and dull mower blades. The best thing you can do for this issue is sharpen the blades on your mower. Winter watering is a must regardless.
Molds and fungal issues usually show up as discolored leaves. They may be straw colored to yellow, tan or purple, most often as spots or blotches rather than full leaves. These will have to be identified individually in order to treat properly. However, GOOD NEWS! They can be prevented by good lawn management practices.
Nearly everything I've discussed here is caused when the lawn is under stress of some sort. Most often, alleviate the stress and you'll alleviate the problem. It's also important to point out that the native grasses are less prone to problems in a lawn. Once again, the type of grass you select for your lawn is important. Choose wisely and save yourself some headaches down the road. I encourage you to get your lawns in good shape this year. If the weather patterns hold, we could be in for a severe drought next year. A strong, healthy lawn will stand a better chance of surviving without problems. If you have any questions, ask a Master Gardener it's what we do.