Dear Iris

Cardboard helps transform lawn into planting space

By COLLEEN T. BELL, Master Gardener Intern | Apr 19, 2012

 

Photo by: JULIE JOHNSTON/Ledger photo  

 

Trees are being planted at the Maasdam Barns using the cardboard method.

My goal is to phase out turf grass except for pathways between beds of a wide range of edible fruit and nut trees, berries, herbs, and flowers (some edible). It’s easy to transform lawn space (or just about any flat space that’s a good garden site) into planting space with little to no digging and no rototiling. Use cardboard!

Why cardboard? Cardboard blocks light and air from turf so it dies. It does let water in and that helps the grass break down. This creates a 4- to 6-inch layer of compost, which attracts worms that will eat the wet cardboard. It’s amazing how loose and “plantable” the soil is within a few months. The worms naturally aerate the soil, which makes it easier for things to grow. The roots need oxygen. (When we rototill, it not only destroys any worms, it breaks down the soil structure, and it takes a long time to build up again. It causes compacted soil.)

This is especially useful for fruit trees because their young roots grow laterally just below the surface. Take away that competition of turf to give them a good start in their new home.

How to do this? If planning ahead, water the area for the new growing space. Mow as close to the ground as possible. Then layer and overlap the cardboard over the entire area to be planted. Leave no grass showing, please. Be sure to remove tape and staples that won’t decompose with the cardboard. Water thoroughly.

The second step is covering the cardboard with about 2 to 4 inches of compost if possible and topsoil if necessary for weight. Water again, thoroughly. This facilitates decomposition and holds the cardboard down.

The third step: Cover area with a layer of mulch to retain moisture until your living mulch is established. This mulch will vary depending on what you are planting.

When you plant in the new bed always leave at least 3 to 6 inch breathing space between cardboard and stem. Don’t let wet cardboard be up against any growing thing, please! Pull the cardboard away from the tree trunk or plant. Tear it out or tuck it under.

If you haven’t done this technique ahead of the time of planting your tree, it’s OK to do it all at once when you plant the trees or soon after. Follow the tree planting instructions as usual. Then mulch with cardboard!
This technique also is useful for making a new flower or vegetable bed. Follow the same instructions for any size bed. If there are a lot of smaller plants in a row just cut a strip out to plant. Then I use folded multi layers of newspaper to go between the small plants because its easier to work with around small plants.

Here is how to use it for fruit trees:  Create a circle about 5 to 6 inches in diameter. Figure the center and measure a 3-foot string and draw a perfect circle to be covered with cardboard. Ideally when you plant your fruit or nut trees, plant a circle of daffodils around the trunk. They are poisonous, so the critters won’t burrow up to the trunk to snack. Do this when you plant the tree. Transplant them from places where they have gotten too crowded. Once you have planted, don’t walk in that circle. It compacts the soil. If you need to get close use a board or stepping stone.

Now the tree needs some company! Plants that will support and aid in its growth and survival! Permaculture design uses the term guild to describe such a group of plants. Comfrey is a good example that fills several functions. The Fairfield Public Library has several books on permaculture and edible forest gardening.

Colleen T. Bell is a Master Gardener intern, a graduate of the permaculture design program and owner and manager of Earth Wisdom.