Organic gardeners often wonder how to kill grass and eliminate lawns without using herbicides—and without excessive work. There's an easy and natural way to do the job in preparation for opening up planting beds. It's a method that involves using newspapers to smother your lawn, which also gives you a chance to recycle the newspapers.
The job goes fairly quickly if you have a lot of newspapers to work with. But the smothering process takes several months to play out, so this method appeals most to gardeners who have time on their side. Lay the newspapers down in the fall if you want to be gardening in the spot by next summer.
Mowing Is Optional
Some gardeners who use this grass-removal method begin by mowing the grass, but this step is optional. The method outlined here will kill tall grass as certainly as it will kill short grass. The one argument in favor of bothering with mowing is that it's easier to get newspapers to lie flat on top of short grass than on tall grass. But either approach will work, so it's really up to you.
Laying the Newspapers
To kill the grass effectively, it's important to keep two things in mind as you lay the newspapers over the lawn:
- The layer of newspapers must be thick: about 10 sheets.
- Overlap each 10-sheet stack of newspapers with the next stack in the row. The overlap should be by a few inches. Likewise, when you start laying a new row, overlap it with the first row (so the overlapping occurs in both directions: up and down, plus left to right).
When you begin laying newspapers, you may find that you're wasting too much time opening up sections of newspaper and counting the sheets (to get to 10). But as you proceed, you'll naturally develop a quicker (if less precise) method.
You'll come to learn approximately how many sheets per section (be it sports or whatever) is the norm with the newspaper publisher in question. Once you get the knack for it, you'll simply start laying sections down, unopened. This will mean laying more individual "shingles" (to use an analogy to roofing a house), but it will speed up the process a lot. It's a shortcut that you'll develop a feel for once you get going.
Although spraying water on the newspapers (to keep them from blowing around) might seem like a good idea, wetting them actually makes the newspapers more difficult to work with. They'll tend to break apart too much when wet. So keep the newspapers dry while you're spreading them.
Since you'll be applying mulch as a final step, a better way to keep the newspapers from blowing is to keep a bucket of mulch handy, so that a bit of mulch can be applied on top of the newspapers immediately if the wind starts to become a problem.
Covering the Newspapers With Mulch
When you are through laying newspapers, go back and spread a layer of mulch (5 or 6 inches) uniformly over the newspapers. A thick layer of mulch will press the newspapers tightly against the lawn, which will smother the grass faster. Now that you're done working with the newspapers, spray some water over the entire area. This will further pack down the mulch and get the sod to rot faster.
Now you just wait (at least several months) for the layer of newspapers and mulch to kill the grass. Sod, newspapers, and mulch will eventually all break down, adding nutrients to your soil. At that point, you'll be ready to start gardening in the space.
Newspapers Versus Cardboard
Many gardeners would like to convert a lawn area to a flower bed (without using herbicides) or start a vegetable garden from scratch, but the thought of rototilling, digging sod out by hand, or even renting a sod-cutter can be daunting. This is especially true if you have a large lawn area.
Killing grass by laying newspapers on it is a great solution for some gardeners, but others find even this method a bit too much work. Since a sheet of cardboard from a box that you break down (corrugated cardboard) covers a greater area all at once than a sheet of newspaper, and since cardboard's thickness means you don't have to stack it 10 sheets deep, some naturally wonder if laying cardboard's a better solution than laying newspaper because of how quickly the job goes.
One of the objections made by experts to cardboard is that it's more impervious than newspaper. So it greatly restricts how much air and water makes it down into the soil. This would be bad news for any plants growing near it.
But this is a classic case of the need to consider context before drawing conclusions. In the context of mulching between the shrubs and/or perennials in a flower bed, using cardboard would be a terrible idea. But if you simply wish to kill your grass so that you can open up the area to plant something else later (after the cardboard has broken down), that objection against cardboard doesn't hold water.
A more serious objection to cardboard will be raised by organic gardeners. While most newspapers nowadays are safe to use in the garden, the type of cardboard found in shipping boxes is more complex and more problematic.
Corrugated cardboard is made up of a liner board on top, another liner board on the bottom, and the corrugated medium in the middle. Glue holds the sheet together. A cardboard shipping box may also have a waxy coating on it, tape, sticky labels, inks to produce lettering or decorative features, etc.
A stickler for organic gardening would be hard-pressed to track down the materials used in each step of making corrugated cardboard to certify that they are all organic. A compromise solution would be to use cardboard only in areas where ornamentals will be grown. Also, if you have lots of cardboard to choose from, choose the type that has no dyes on it and no waxy coating.
These considerations aside, killing grass with cardboard works very much the same way as killing grass with newspapers:
- Lay the cardboard down on top of the grass.
- Cover the cardboard with mulch.
- Hose down the whole area.