How to Grow a Chemical-Free Lawn and More Soil Science

Hand-crank cyclone spreader
Hand-crank cyclone spreader
Hand-crank cyclone spreaders are an easy way to apply grass seed and amendments to your lawn.
©David R. Clark, CNLP 2022

A lush, green, healthy lawn can be an asset to your home landscape and it’s just a rake away from perfection!

After our long, cold winters here in Western New York and Southern Ontario, many folks view the annual greening of our lawns in spring as a true sign that the snowy months are about to become a memory. Or so we hope…

The most important thing one can do for a truly great lawn (and for other garden areas) is to perform a soil test. What this procedure gives you is a current snapshot of not only what the nitrogen, phosphorus, and potassium macro-nutrient levels are in your soil right now, but it also gives you the pH level, which is more important than the N-P-K as it affects nutrient availability in the plant root zone. Plan to perform a soil test in March, once the soil thaws. Test kits can be purchased at your local garden center.

The pH scale is read from 1 ->14, with 7 being neutral, below 7 being acidic, and above 7 being alkaline. Our local soils are rarely highly alkaline. Most turf (lawn) grasses grow best in a slightly acidic environment with a pH range of 6.2 -> 7.0. Soil pH can be lowered by half a point—from 7.0 to 6.5, for example—by increasing soil nitrogen. Adding compost, manure, or organic soil amendments like alfalfa meal to the soil can help drop pH over time by increasing bacterial populations. Organic matter “buffers” soil, especially sandy soils. Soil acidification also makes life more difficult for many weeds. Weeds are early successional plants that evolved in thin, alkaline soils. In acidic soils, many weeds are weaker competitors.

Espoma Garden Lime to raise soil pH.
©David R. Clark, CNLP 2021

Work lime (to raise pH) or sulfur (to lower pH) at least 6 inches deep into the soil for the best and quickest results. Please note that lime and sulfur can take up to 2 – 3 months or longer to react with the soil. Sulfur works best during the warmer months of the year, as it needs the soil biota (the living bacterial and fungal portion of soil) active. If your soil test shows a neutral pH of 7.0, and you want to lower it to 6.5 -> 6.8, you would need to add 7 pounds of sulfur per 1000 square feet (1.2 pounds per 100 square feet). A soil test should be performed 3 months after application (June) and may require that the soil be treated again (September). Mid-August into September is the best time to renovate your lawn.

If your lawn is infested with crabgrass, the use of a pre-emergent herbicide in spring will prevent the seeds of this pest from germinating. Corn gluten meal is a good alternative to traditional chemical pre-emergent herbicides. Plan to apply the corn gluten when your forsythia shrubs are in full bloom. Allow a 6-week window after applying corn gluten before over-seeding your lawn, as it will also keep grass seed from germinating!

What about fertilizer? I bet your soil test shows that you have little to no nitrogen (for leaves and shoots), a deficient level of phosphorus (flowers and roots), and a deficient level of potassium (tubers, roots, and fruits). Fertilizer bags have numbers on the label such as 5-10-5, 10-10-10, etc. These numbers represent the percentage of nitrogen, phosphorus, and potassium respectively. Good lawn fertilizer has the approximate numbers: 10-16-20.

Benefits of grasscycling: Grasscycling supplies about 20-30% of the fertilizer requirements of most grasses. Leaving your clippings on the grass after mowing is beneficial as they return nutrients back to the soil. However, it is only beneficial if you follow proper watering, mowing, and fertilizer guidelines. Avoid over-fertilizing as it can cause vigorous shoot and stem growth, which contributes considerably to thatch buildup.

What about mowing? This is my least favorite, but necessary landscape task, when I would rather be outside planting beautiful flowers and keeping up with other more important gardening tasks. Dull mower blades rip and shred the grass leaf blades, providing you with a brownish cast to your lawn, even with the best care. Keep your blades sharp. Raise the mower deck to no less than 2 ½”…better to 3 or more inches. Lawns with a 3” leaf blade length shade the plant crowns and soil surface, conserve moisture, and reduce weed infestations, including ground ivy.

Here is a Lawn Care Schedule:

  • March- perform soil testing.
  • April – weed management: apply pre-emergent corn gluten meal, and Borax (to control ground-ivy: (see Mid-August to October entry)
  • Late May – apply fertilizer, right around Memorial Day.
  • Summer- lawns need 1” of water per week to survive, and 2-3” of water per week to grow. Water in the early morning hours to reduce disease opportunities. Irrigate to 1” depth, 2-3 times per week. DO let your lawn go dormant during the hottest part of the summer. Not only will you avoid getting sun-burn and heat stroke, (and enjoy a margarita on yourdeck), this summer dormancy is ok for turf grasses. Don’t worry- it will green up once temperatures fall and moisture becomes available. One of the best choices of drought-tolerant grasses are fine fescues. One of the worst choices of drought-tolerant grasses is ‘Kentucky Blue”.
  • Mid-August to Mid-September: Re-seed and /or renovate your lawn. Apply Milky-Spore and/or Grub-Ex to control grub and Japanese beetle populations. Do not treat you lawn routinely with insecticides.
  • Mid-August to October – Control broadleaf weeds. Our good friend “Creeping Charlie” or Ground -Ivy, Azadirachta indica, is a difficult lawn thug to eradicate. Borax, commonly found under the trade name of “20 Mule Team Borax” applied at the rate of 20-30 oz. (by weight)/ mixed in 1 gallon of water and applied as a spray, may provide control, although most turf professionals recommend using a commercial herbicide.
  • November – Thanksgiving Day is the best time to fall fertilize your lawn. So, put the turkey in the oven, and get out there and fertilize!
  • November forward – curl up with a good gardening book, and enjoy your winter holidays. We’re gonna do this again next year!

References

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