How to Prepare Soil for Kentucky Bluegrass Seeds
Not only will a poor soil cost you extra money keeping your lawn watered, but also makes for a poor looking lawn. As a rule: healthy lawns grow in healthy soil. Many people dump loads of fertilizer onto their lawn (another extra cost) to make it as green as possible and mask their soil’s shortcomings. But this is a short-term, habit-forming fix. A well-prepared soil, combined with the best genetic-color Kentucky bluegrass seed varieties available, will save you time and money and give you the best chance at a picture-perfect lawn.
A good soil is well-structured. The better the structure the easier it is for water to absorb and percolate deep into the soil profile. Clay soils are dense and compact easily, making them slow to absorb water and nutrients. This makes them prone to losing water to runoff and evaporation before much of it gets down to the roots. Sandy soils allow water to move through the soil too quickly and evaporate from the soil too easily. In a well-structured soil, water is held deeper in the soil and is protected from summer evaporation. This encourages your lawn’s roots to grow down deeper than they would in a poor soil, giving them access to additional water and nutrients which are out of reach of shallower rooted plants.
Healthy soils need various components such as organic matter, diverse particle sizes and enough pore space to hold oxygen and water. Poor soils suffer from a shortage of most or all of these components, but organic matter is the solution to every one of them. Decomposing organic matter provides nutrients for your grass seed and also increases the diversity of soil particles (instead of the evenness of a pure-sand or pure-clay soil). The various particles from the added organic matter create a matrix of space between the soil particles that allow water and oxygen in and give roots room to grow. Taking extra steps before you plant your Kentucky bluegrass seeds will produce a healthy soil, giving you a thick, lush lawn needing less water and fertilizer.
- Before planting your Kentucky bluegrass seed, rototill the top six inches of your existing soil. This adds oxygen and breakups any compacted areas that restrict water absorption and root growth.
- Till in organic matter such as black topsoil, compost, shredded yard waste (leaves, grass clippings, etc.) or an organic matter-based, slow-release fertilizer.
- Add any additional soil amendments as suggested by your local county extension agent. Your local agent may recommend you get your soil analyzed first. Follow their instructions on where and how to have your soil tested.
- When mowing your lawn, don’t bag the clippings. Instead, set your lawnmower to its ‘mulch’ setting. Lawn clippings provide your Kentucky bluegrass with a steady input of organic matter throughout the growing season that will slowly decompose on the soil surface.
- Have your lawn aerated at least once a year (twice—fall and spring—if you have high-clay soils). Aeration breaks-up compacted soils, opens up space for new growth, creates a pathway for oxygen to enter the soil, helps thatch and clippings to decompose and allows water to infiltrate into the soil easier.
- Top-dress your lawn with black topsoil, compost or any other fine-particle organic matter that can be easily worked down to the crown of the grass. Even sand—either alone or blended with topsoil or compost—can be a helpful top-dressing to improve soil structure (especially in high-clay soils). Top-dressing your lawn shortly after aerating, before the holes have had time to close back up, can be particularly beneficial. Note: It is important never to top-dress a light sandy soil with a heavier top-dressing. This will cause soil interfacing and restrict root depths.