Prepare for Planting - Cardboard and Mulch

Do you have a garden bed that you plan to ReWild (or otherwise re-plant) in Spring or Fall?

As they say, an ounce of planning is worth a ton of fixing. Starting your planning a few weeks early will save you many many hours of unnecessary weeding grief.

Here is how you can plant and maintain the new design easily, without “old” plants or weeds popping their heads back up.

  • Step 1: Eradicate the plants that are already in the bed. Pull out the ones you can, and neatly trim others to ground level.

  • Step 2: Lay down cardboard on top of the plot. This will prevent weed seeds and persistent grasses from popping back in Spring before your new plants establish.

    • If this is a small planting then just use cardboard boxes that came from Amazon or Walmart, or wander by the grocery store dumpsters. Be sure to pull out all the little plastic before you lay the cardboard on the ground.

    • For bigger plantings, Costco is one of the best places to get Cardboard. Costco sheets are flat, don’t have any staples, dyes or markings, don’t need to be “unboxed” and ready to lay out

      • Go back to the loading dock, and ring the bell to meet the supervisor on staff. Explain that you would like sheets of cardboard that they are throwing away. Often they have a bunch back there. Sometimes, they may ask you to wander the aisles and pick it up yourself. We have picked many may sheets on prior visits.

    • Estimate cardboard based on the area of your yard. One sheet from Costco is about 10 square feet. Get some extra so you can overlap sheets when you lay them down. Gaps are not good.

  • Step 3: Put down mulch on top of the cardboard

    • The mulch holds the cardboard in place. Check out this article for what mulch is and your options for mulching.

    • Ideally, pick a double or triple-shredded hardwood mulch that has been composted to kill all the weed seeds. There’s nothing wrong with using natural mulch. The best is triple-shredded mulch is best but not easy to find. Be sure to leave at least 3” clear from the crown of the perennials.

      For areas with shrubs/trees, you can use wood chips. This we recommend to get before the foliage leafs out. If going this route, most tree services will be glad to drop them for free but make sure to ask for hard wood chips only.

    • Avoid dyes on the mulch. It’s all going to break down into your garden.

    • Go for about 3” of mulch. How many bags/cubic yards does that translate to? Use this handy dandy mulch calculator to figure it out!

    • For small areas, you can buy by the bag. For larger areas, avoid the plastic and cut costs by ordering wood mulch by the cubic yard and getting it delivered.

  • Step 4: The cardboard will kill existing plants over a fwe weeks and the mulch will break down in about a year. Come spring or fall, you are ready to plant.

    • When you plant, push aside the mulch and make a hole through the cardboard, digging into the soil.

    • The best way to make a hole is using a drill and a plant auger. How? Watch this video … and yes, Home Depot, Amazon and your local hardware store will likely carry the plant auger.

    • Add soil or compost into the hole, if necessary, and place your new plant in the space.

    • I usually leave an inch or two between the mulch and the plant to prevent dampness on the stem.

  • Step 5: Make a design and plant to the design. For ease of maintenance and improved beauty, plant groups of the same species in eye-catching “flows” rather than mix everything up (unless you’re making a meadow!). Design makes it much easier for you to spot “unwelcome volunteers” that got between your plants in a pattern.

    • Leave space to get in and weed!

The advantages of using cardboard/mulch to prepare the ground are that the cardboard naturally acts as a weed barrier for the coming year, while the mulch breaks down and provides a great layer of humus to fertilize the soil.

When you rewild your yard using this technique, you don’t need to fertilize, and the need for weeding is cut down to almost zero. (Never quite zero - nature, and especially dandelions, will find a way around everything you do …)

Cardboarded, mulched lawn with native plants placed in drilled holes.  (Yes, you have to wait till they grow out!)

Cardboarded, mulched lawn with native plants placed in drilled holes.
(Yes, you have to wait till they grow out!)

The same garden after 2 years