Do you ever notice how some of your neighbors have perfectly green and flawless lawns? The most frequently asked question I am asked is, “How do I get my lawn to look healthier?” Creating a beautiful lawn is simple if the lawn is kept healthy. Just follow these simple guidelines (or find a good lawn service and make sure they follow them) and YOU will be the envy of your neighborhood. First a review of Plant Physiology 101...
Fertilizing:
For established lawns, I recommend that you do the most fertilizing in the late summer months and in the fall. This will keep your lawn greener longer in the fall and will allow for an earlier greening in the spring. Late season fertilizing will promote higher levels of plant energy reserves in the following spring and summer months and will also give your lawn better tolerance against summer stresses and diseases. When fertilizing, divide the fertilizer needed for your lawn in two and cover the area twice, alternating directions of your applications. This will help prevent streaking and burning. Always water your lawn immediately after fertilizing. If you are good at predicting weather, you can fertilize right before a steady rainfall. Make sure you sweep up any fertilizer that spills or is over sprayed onto paved surfaces to prevent it from ending up in our beautiful waterways!
When fertilizing your lawn, there are normally three nutrients to consider: nitrogen (N), phosphorus (P), and potassium (K). Of course, there are other nutrients that are necessary for healthy lawn growth, but nature usually provides them in ample amounts.
Nitrogen:
Nitrogen helps the grass to grow and also produces the rich, dark green color. How much nitrogen is needed? Every lawn is a bit different. The more a lawn is watered, the more nitrogen is needed during the growing season. Grass clippings that are allowed to fall back onto the lawn provide some nitrogen, but usually not enough to keep up with the needs of a growing lawn. It is usually necessary to add additional nitrogen by fertilizing. Nitrogen fertilizers come in soluble materials (quickly available to lawn) and slow release materials (slowly available to lawn). The water soluble fertilizers make the nitrogen available immediately and a sudden growth spurt will occur, followed by a fast depletion of the available nitrogen. If this type of fertilizer is used, it will be necessary to make frequent applications to see a uniform growth over a period of time. If too much of this type of fertilizer is used at one time, your lawn could “burn”. The slow release nitrogen materials depend on the temperature of the soil, microbes, and moisture to gradually decompose the materials and make the nitrogen available to the plants. This occurs over a longer period of time. Hot weather and ample water will increase the absorption of the nitrogen. Most good fertilizer products on the market today have a combination of fast and slow releasing nitrogen so you will see immediate benefits and long lasting results.
Phosphorus:
Phosphorus stimulates early root growth. It binds tightly to the soil particles which means that it stays in the soil for a long period of time. If your soil has a sufficient supply of phosphorus, as most metro area lawns should, you probably won’t need to add supplemental phosphorus. In fact, as this compound contributes to algae growth in our lakes and streams, phosphorus has been banned in the seven county Metro
Potassium:
Potassium helps in the synthesis of some plant components and in the regulation of many physiological processes. In a nutshell, if your lawn is low in potassium, it will be prone to diseases and environmental stresses. Like phosphorus, it binds tightly to the soil particles so it is broken down and utilized very slowly. If your lawn has a sufficient supply of potassium, you most likely will not need to add supplements of this nutrient. If your lawn is low in potassium, which is typical in sandy soils, it is very important to add potassium to your lawn to maintain optimum health.
Confused? If your lawn is not healthy, I recommend that you have your soil tested to get an accurate diagnosis of the problem. If your lawn seems to be responding to your efforts, keep up what you are doing and continue showing off your gorgeous green!
Mowing:
Mowing on a schedule will keep your lawn thick, smooth, uniform, and will keep the weeds at bay. Weeds don’t want to compete with a healthy lawn! How often should you mow? It depends on how fast your lawn is growing. You should mow no more than 1/3 of the length of the grass at each mowing. So to keep a healthy 2-3” lawn (can be slightly shorter for fast growing lawns), your lawn needs to be cut before it has grown to 3-4” long.
Watering:
Fortunately, turf grasses can survive the dry periods we experience in Minnesota
Aeration:
Aeration is the removal of small cores of soil from the lawn. This helps reduce compaction of the soil and enables the grass roots to expand into the soil. Aeration also helps create a more durable lawn that is more resistant to disease and drought. The plugs of thatch and soil will break apart and disappear into your lawn after a few weeks. Thatch is the accumulation of tightly meshed, dead and living stems and roots that build up between the surface of the soil and the grass. If the layer of thatch becomes more than 1/2” thick, your lawn’s root system can be compromised. Disease and insects can take advantage of a weaker system and dry spots may appear. Aerating your lawn is a very effective way to get thatch to decompose and reduce thatch build-up. Meanwhile, the aeration holes will begin to fill with actively growing roots resulting from the additional oxygen, moisture and nutrients provided by the aeration process.
Aerate a new lawn in spring and fall for the first few years, then at least one time per year once the lawn is more established. With repeat aerations over time, your lawn’s root system will become more dense and grow deeper into the soil. You should be able to increase the time between waterings without your lawn showing wilt and stress. And your lawn will have a greater tolerance of heat, drought, and disease.
Controlling Weeds:
Maintaining a thick, healthy, green lawn is the best weed control there is. A lawn that is properly fertilized, mowed, watered, and aerated will defend itself against weed infiltration. If a few pesky weeds crop up, use herbicides to kill them.
The best way to control annual grass weeds such as crabgrass is to use preemergent herbicides in areas where crabgrass was observed the previous year. These chemicals kill the plants just after the seeds germinate. To be effective, it should be applied by May 15 in a normal year (if you can figure out what a normal year is!).
Broadleaf weeds, such as dandelion, plantain, clover, or creeping charlie can be controlled by selective postemergent herbicides without damaging the grass plants. Apply when the weeds are young. Take care not to overspray onto desirable broadleaf plants, flowers, shrubs, trees.
Most perennial grass weeds such as quack grass or tall fescue can be controlled with chemicals by using nonselective postemergent herbicides. These chemicals kill all plants, including the grass, so reseeding may be necessary. Always carefully read and follow all instructions on the herbicide label before using.
Take your shoes off and enjoy!
