From sod to garden

Right now I'm devoting most of my time to pruning and mid-winter garden projects. But I came across a response I wrote a while ago to a question (not on this blog) about the best way to remove sod. If a January answer does not seem timely (you can't use a sod-cutter when the ground is frozen or sodden), it is not completely off topic either -- spreading cardboard and mulch in the winter in anticipation of spring is perfectly suitable. Thus, I am discussing it here and now. Originally I described three ways, each with its advantages and needs. There really are five, but four and five are half-way measures. The three main ways -- cardboard and mulch -- sod cutter -- rototiller -- requires some heavy lifting, literally. The lightweight ones -- killing sod, and over seeding -- are kind of just partial answers, with their own array of plusses and minuses.

While there are a number of compelling reasons to get rid of lawn, don't eliminate sod to eliminate work (like mowing, weeding, and edging). BEFORE you get rid of that lawn, have a plan in place for what you will install in place of the lawn that you remove. AND, be ready to carry it out almost immediately. Any untended patch of ground devoid of lawn becomes a patch of weeds, three times harder to maintain.

This is not to say that eliminating a lawn is a pointless task. Lamentably, a lawn never mows itself. Sometimes lawn IS a pest -- especially along the edges. But IMHO, the best reason to eliminate lawn is when its job as a placeholder is over and you are ready to expand the garden. If you malign your lawn because of the weeds growing with it, or only because you don't like to edge it, keep in mind that when the sod goes away the weeds may not, and then it is harder to control and contain. To read about one of my favorite lawn weeds to hate, and how I made peace with my lawn by controlling the weed, see my blog on eliminating hairy cat-ear, (Hypochaeris radicata).

Ok, thanks for reading.

1) Cardboard and mulch

With this you have to gather supplies, sometimes a lot. Usually this techniques is very effective if done deep enough. "Mulch" can be anything from leaves and grass clippings to garden soil to composted manure to wood chips, depending upon what you are planting. I have done this many times and, despite the following cautions, I like it a lot.

The greatest caution is that really bad weed roots -- bindweed or quackgrass -- may flourish under the cardboard. The lawn is the biggest weed in the garden, mostly an easily managed weed -- until it isn't.  I like to cut a trench along the cardboard edge so that the remaining lawn does not invade and become a weed. You can plant small things in it right away, but it takes half a year for the sod to break down and even longer before worms, moles, ants, etc start to naturally till the soil and merge the margins.

Planting small stuff and veg and annuals on top of cardboard is not a problem. But you do not want to plant larger plants on top of the cardboard, nor will you want to cut through the cardboard and sod after dumping all the mulch on it. Instead, dig a hole in the sod for the big plants, and then put down the cardboard and mulch everywhere else. The mulch eventually breaks down and settles.

How deep you plant is kind of tricky. If you plant too high, the shrubs can end up with their roots exposed as the mulch disappears. Along the native shrub edge we inherited, where this cardboard and mulch system was used, we have some shrubs standing high on their roots, looking like a miniature mangrove forest minus the salt water. If you plant too low, the crown can be buried under too much mulch.

2) Sod cutter

Sod cutters are a brute of a gas powered machine, with a vibrating sod-cutting blade.  Ahead of cutting the sod you need to have mowed the lawn.  Then you fire up the sod cutter, then walk behind the beast as it cuts free a perfect sod strip.  You can roll up the strips and move them elsewhere. The undersoil is unaffected, meaning it is ready for mulch -- but you still need to chop or till the underlying soil before planting.

A sod cutter is best where the lawn / sod is an even surface, with few tap-root weeds -- mostly turfgrass and turf-type running-roots such as clover.  It is not as suitable on a weak lawn with many tap toot weeds, and not workable in soft wet conditions.  It does reduce the amount of grass that resprouts as weeds, and leaves a very finished look.

I really like a sod cutter when extending an existing shrub bed where either mulch or tilling would look awkward / lumpy. After a bit of  practice it is kind of fun and easy. If the sod is in good shape you can give it away, maybe even sell it and recoup some (all) of your rental costs.

3) Tiller

There basically are two types of tillers, front and rear tine. Front end tillers are cheaper, lighter, and somewhat more maneuverable, but they bounce more (and you with them) and the end results are rougher. A rear tine produces results that are smoother, more "professional".  If the soil is rocky or with lots of big roots you  will still have a good work-out. Either way, you are chopping grass and weed roots into the ground that have the potential to resprout, and of all the techniques requires the most follow-up vigilance. The big advantages are that with  a tiller you have the least amount of materials that you either haul in or haul out, and as you till you can blend in various amendments.

After tilling the soil, one can plant a cover crop, discussed further in the next section on overseeding.

4 Overseed / plant

One can modify a lawn by overseeding it with different grasses and forbs.  It is not the most effective or efficient, but can be a simple, interesting solution if one has a certain level of tolerance.  One can choose a mix of flowers, or cover crops, or leafy greens.  Certain "ecology" lawn mixes include a mix of flowers and low herbs that tolerate occasional mowing. Mostly these are not techniques that eliminates the lawn, but they can alter it.  

A person can even plant winter wheat or other winter grain in the lawn; it will change the soil texture and possibly the plant make-up.  As a means to grow grain, it is amusing if perhaps not the most effective: the grain will mature in summer, by which time the lawn grasses will be probably also be quite tall and also germinating seed.  

One can experiment in what and when one plants.  After planting, consider tilling up the old sod several months later, or vice versa -- i.e. till first then plant a cover crop.

5 Chemical death

There are a number of herbicides available from fairly benign -- Acetic acid 20% (household vinegar is acetic acid diluted to 5%) -- to rather nasty.  For what it is worth, in my book Gyphosate (Roundup©) is somewhere in between nice and nasty, but rarely a first (or 2nd or 3rd) choice for sod elimination.  

In every case, herbicides are far safer when the instructions, such as application conditions and product dilution, are followed.  Of those who ignore the instructions, homeowners tend to be the worst in part because no applicator license and oversight is required.  Even if you do not need an applicator license, consider reviewing the pre-license applicator materials.

if you do kill the sod chemically, you still have not eliminated the sod, simply killed the plant growth.  Before planting you will still need to cut through or rototill the sod; if you simply are top-dressing the old sod with a mulch this step can be skipped.