During March and April, homeowner thoughts turn to the quality of their lawns. Lawn quality is measured in terms of color, density and uniformity. Soil conditions, fertilization, and watering are the factors that affect lawn quality. Of these, the condition of your lawn’s soil and your fertilization schedule have the greatest impact. It’s entirely possible that the grass will be unable to take up the nutrients provided by spring fertilization due to poor soil conditions. Is the soil beneath your grass hard and lumpy? Does water run off after the grass has been irrigated? Does it always seem “thirsty”, i.e. wilts by the next summer’s day? Is it not as green as it should be? If so, then your lawn is a prime candidate for core aeration.
What is Core Aeration?
Core aeration is a performed with a special machine that pulls out plugs of soil. This opens up the soil structure, allowing air, water and fertilizer nutrients to penetrate more deeply reaching the grass roots. Core aeration makes the soil more friable, “crumbly”, a condition allowing roots to grow down rather than up. When roots are growing up this is thatch. Friable soil also helps earthworms, nature’s core aerators, to better able tunnel through the lawn, moving more nutrients and water. Plus the casings they leave behind are excellent fertilizers. Mid-March through April is a good time to do this as the soil is usually softer from our spring rains, making it easier to core aerate.
Whether you perform the core aeration, or hire a company for the job, make sure the machine being used has the appropriate length tines and spacing. Soil scientists and turfgrass experts recommend tines are a minimum of 4-inches in length, with a spacing of 2- to 3-inches. If the tines on the machine are farther apart, it will need to go over the same area multiple times. First, make sure to mark off sprinkler heads – you don’t want to run the machine over them. Not only will that damage them, it will also damage the machine’s tines making it useless. Core aerate the lawn. The cores then can be either left to degrade naturally, or be broken up a day or two afterwards by simply mowing over them. Apply an organic lawn fertilizer at 2 — 3 times the recommended rate. The reason for choosing an organic fertilizer is that compacted soils are not only nutrient poor, they structurally weak, which is why they became compacted in the first place. Organic fertilizers contain materials that help build up soil structure. Because organic fertilizers have high amounts of insoluble nitrogen, this amount will last longer, allowing you to skip that midsummer feeding in July if you so choose. Once this has been done, water the lawn thoroughly to help move both the soil and fertilizer into the holes. The holes will eventually fill in, completely disappearing within month.
Why Spikes And Rollers Don’t Work
Do not aerate your lawn by sticking sharp objects into the soil that do not remove a core. These only push soil aside to create a hole. In other words, they actually compact the soil even more. So wearing spikes on your shoes while mowing or walking on the grass is not a good technique. Reducing “humps” in the lawn by rolling over them with a heavy roller only smashes the plants and compacts the soil. If you have a lumpy lawn, raise the surrounding low areas by spreading no more than 1/2-inch of topsoil mixed with compost, or humus. Do not use straight topsoil as it is too heavy.
Cultural practices, particularly fertilization is the next factor to consider. Common sense, including timing and refraining from overfertilization is key to lawn quality. Overfertilizing in one application causes an over abundance of grass to mow, weakening it and making it susceptible to disease and insects. Poor timing of fertilizer application increases the likelihood of infestation of Chinch Bugs. Take-All Patch is a serious fungal disease whose symptoms become only apparent in the heat. Controlling it is hard, and fertilizing the lawn too early defeats the control measures.
Timing, distribution, and application rate of lawn fertilizers must correspond to grass requirements. St. Augustine and Bermuda grass are heat loving plants, and will readily grow when both the soil and air temperatures are to their liking. Synthetic lawn fertilizers contain a high amount of soluble nitrogen. This means that it readily dissolves in water making it immediately available. EZ-Gro and Nitro-Phos make excellent lawn fertilizers, but fertilizing St. Augustine and Bermuda grass lawns with them earlier than when they are actively ready to grow is wasting money. Thus they should be applied when environmental conditions are to the grasses’ liking. This means that when the weather is consistently warm enough and the grass looks like it is starting to actively grow. Organic fertilizers can be applied earlier, because they contain high amounts of insoluble nitrogen. This means that it dissolves slowly in water thereby lasting longer. Plus, this insoluble nitrogen must be decomposed by the beneficial soil microbes in order to make it available to the grass roots. Again, you do not want to apply these too early either, because the grass is not ready to take up the nitrogen contained in them.
Last, but not least, moderately or heavily shaded areas should not be fertilized as much as areas receiving full sun. Grass growing in shady areas is more succulent and has a weaker root system than grass growing in full sun. Applying too much fertilizer will not make the grass grow more thickly in those areas, it will just further weaken it. A practical resolution is to plant those areas with shady loving plants such as Ardisia, Ferns, Dwarf Mondo Grass, Variegated Lirope, Impatiens, Torenia, Shrimp Plant, Australian Violet, Pigeonberry or others.