Applying a light covering of straw over newly sown grass seed significantly aids in successful lawn establishment. This organic mulch acts as a protective layer, shielding delicate seeds from environmental stressors like heavy rain, strong winds, and birds that can displace the seed. The straw also helps regulate soil temperature and retains the moisture required for germination and initial root development. Understanding the correct material selection and application technique transforms this simple step into a powerful tool for growing a dense, healthy lawn.
Selecting the Proper Material
Choosing the right material is essential, as using the wrong kind of mulch can introduce significant problems. The correct choice is straw, consisting of the hollow, dried stems of cereal grains like wheat, oat, or barley after the grain heads have been removed. This material is lightweight, fluffy, and generally free of viable seeds, preventing the introduction of competing plants. You should specifically look for “weed-free” straw to minimize any chance of unwanted seeds sprouting.
It is crucial to distinguish straw from hay. Hay is made from the entire flowering body of grasses or legumes like alfalfa and is primarily used as animal feed. Hay bales are heavily laden with seeds that germinate readily, leading to weeds and grasses that compete directly with the young turf seedlings. Selecting a clean, golden-colored straw ensures you are providing protection without planting a future weed problem.
Calculating the Coverage Density
The goal of applying straw is to create a thin, protective veil over the soil surface, not a dense, insulating blanket. The correct density is achieved when approximately 50% to 75% of the soil remains visible through the straw layer. This light coverage, often described as a “thin veil,” allows sufficient sunlight to reach the soil and emerging seedlings for photosynthesis and growth. If the straw layer is too thick, it will smother the seeds, blocking light and trapping excessive moisture, which can lead to seedling death or fungal disease.
A single standard square bale of straw should be sufficient to cover an area ranging from 500 to 1,000 square feet when applied lightly. Using too little straw leaves the grass seed vulnerable to being washed away by rain or eaten by birds, making the protective layer ineffective. Aiming for a consistent, light application ensures the mulch retains soil moisture and stabilizes the seedbed without inhibiting the young grass plants.
Applying the Straw Evenly
Achieving a uniform application requires preparing the straw bale first. Instead of spreading the bale whole, break it apart and loosen the tightly packed material, or “fluff” it. This separates the individual straw pieces, preventing the formation of heavy clumps that would smother the grass seed.
Work in small, manageable sections, taking a generous handful of the loosened straw at a time. Distribute the material using a gentle broadcasting motion, scattering it lightly over the seeded area. It is beneficial to work backward out of the area to avoid disturbing the freshly spread straw and underlying seed. Consistency is paramount, so check the coverage frequently to ensure the bare soil is only partially obscured. After the straw is down, lightly patting it with the back of a rake can help settle the material and establish better contact with the soil, preventing it from blowing away in the wind.
Post-Application Watering and Removal
Once the straw is applied, the initial watering settles the seed and the mulch layer. The area requires a deep, gentle soaking to saturate the top inch of soil without causing water runoff that could displace the seed and straw. The straw then modifies the watering schedule by reducing the rate of water evaporation from the soil surface. This moisture retention is a primary benefit of using straw.
The new seedbed must be kept consistently moist with light, frequent watering sessions until the grass germinates and reaches a height of about two to three inches. This often means watering two to three times a day for short durations, ensuring the top layer of soil stays damp but not saturated. The straw does not typically need to be removed; when applied thinly, it decomposes naturally over time, adding organic matter to the soil. Once the grass is established and has been mowed a few times, any remaining straw can be lightly mowed over, allowing the clippings to further break down the mulch.