Documents: Gardening From: Gardening From Alaska:

A Tale of Two Lawns
by Jeff Lowenfels
by Jeff Lowenfels

email: jeff@gardener.com

Jeff is the Past President of the Garden Writers of America, a columnist with the Anchorage Daily News, Host Alaska Gardens and Supporter of Plant a Row.


June 5, 2016

I have two lawns.

The first has never been fertilized or limed and hasn’t even been watered much over the years

It is as green as lawns come, soft to walk on, a joy to mow and incredible to behold. And for all the lack of attention paid to it, there are darn few dandelions. The robins are all over it and every time it rains, there are so many wormholes, it looks like the Nike golf shoe testing grounds.

Up until this year, the second lawn was also really green, but that was because it started out each spring (and finished up each fall after the first frost) with an application of liquid or granular, quick-release, high nitrogen fertilizer, whatever was on sale at the time with the first number in the label’s trilogy above 20. Every other year it was limed in the fall and more recently, because it started to need it, has even had a mid-summer feedings, too,

It, too, was green, but no robins hunted for worms on it. The nitrogen and phosphorous salts and the lime drove the worms away and killed the bacteria and fungi in the soil. Withhold the hits of lawn food and it would lose its luster as there was nothing else providing nutrients. And without the natural buffering by the soil life, the pH was always out of whack so there were occasional moss problems that had to be dealt with and increasing numbers of mushrooms.

In the first lawn, bacteria and fungi tie up nitrogen from grass clippings and leaves. This they release to the grass’ roots. The whole soil food chain is involved right up to the robins that eat the worms. As they search, robin’s spread some of the protozoa that eat the bacteria that release the nitrogen that makes the lawn green.

It is a beautiful system. Nature rules, feeds, waters and, even adjusts the pH. I only have to mow.

If your lawn is like my back yard, however, to stay green you have to feed it nitrates two or three times an Alaskan summer. We are now learning that the soil conditions these create make for weedy lawns that induce aphids into the birch tree and worse.

Moreover, the particular types of soil life needed for trees and shrubs to thrive in the lawn (fungally dominated) is missing and things you plant in the lawn are not performing up to par.

Moreover, without bacterial slime and fungi hyphae to bind soil particles, worms and microarthopods to create drainage, the soils become compacted, the lawn “blotchy.”

So here is my advice. Now that you have watered your lawn for a month, it is showing its true color(s). If you want it greener, now is the time to apply high nitrogen fertilizer, granular or liquid. The latter is easier because you can use the supplied hose-end sprayer. Do yourself a favor: cut the dose in half to see if that is effective before you put the second half on. Wait two weeks and see.

Or, better yet, switch your lawn from chemistry to biology and turn it into the likes of my front yard where all you have to do is leave the grass clippings on the lawn, mulch up the leaves in the fall instead of bagging them and, if you really see the need, occasionally throw down some low number, slow-release fertilizers.

To do this you have to restore the soil biota. You don’t have to rush. You can simply cut back on the amount of high nitrogen fertilizer you use every year until you use up what you have. Or you can apply dilute amounts of your favorite fertilizers over the summer. This is much less harmful to soil life.

However, here in Alaska, the quickest way to achieve freedom from constant lawn feeding is to stop using high nitrogen fertilizers, cold turkey, and apply a light covering, ½ inch or so of plain old, untreated, (no fertilizer or lime) Alaskan topsoil. Two or three cubic yards will do most any yard.

This top dressing provides organic matter to get life going again in the lawn soils. Consider, too, an application of bacterially dominated compost tea, 5 gallons per acre as a substitute or supplement.

You can also substitute soybean meal, (available at any feed store and at many outlets packaged by Whitney Farms-3lbs per 100 sq ft.)) or Cottonseed meal or Alaska White Cod Bone (local stuff) for the fertilizers you are now using. There are “gentle” fertilizers that feed proteins and carbohydrates to the bacteria so they can do your work for you.

In addition, you can add seaweed fertilizers for micronutrients and even mycorrhizal fungi; the latter especially should be mixed in with lawn seed when planting new lawns. These mycorrhizal fungi will extend the reach of your grass plants’ roots allowing them to mine for phosphates and micronutrients as well as water.

Either way, the choice is yours.

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