Using Cardboard as Garden Mulch.

I may be a registered member of the Mulch Supporters Club but I never understood the Permaculture fetish for wet paper.

More trouble than it's worth.

Laying out the beds at the Vetiver plantation sure enamoured me to cardboard as a mulch understory and now it looks like I'm addicted.

Cardboard, after all, is mashed up wood chips...and it's available any and everywhere. More so, in fact, than newspaper.

So I started using cardboard keenly and experimentally in the kitchen garden.9779368456?profile=original

The DIY is simple.

  1. Using a piece of cardboard of a size that can cover the soil around a seedling -- place it on the soil surface or even over any weeds.
  2. 'Nail' the cardboard into place with a tent peg. (You will pull the peg out when the seedling's growth consolidates).
  3. Using a stabbing tool that enlarges  to a broader gauge than its point, stab a hole in the cardboard and through to the soil underneath.
  4. Wiggle the tool about to widen the hole diameter both in the cardboard and the soil below. Make it wide enough to easily accommodate your seedling.
  5. Insert your seedling into the hole to plant.

Short star posts, chisels, sharpened sticks or dowels will work well  as stabbers.

You can plant in any pattern  or any distance between plants according to your preferences.

(Image above left :Seminole Pumpkin seedling on a cardboard mulch platform)

9779368685?profile=original9779369282?profile=original The cardboard  may not look House & Garden  'neat' but that will be temporary as the plants will grow to cover and shade it. Thereafter, it will rot down.

Indeed, once you have hosed the plants in and soaked the area the cardboard will adapt to the contour below.

I've already had some success with this method. It certainly makes for easy work and ticks  a lot of mulching boxes.

The primary perspective -- that now rules my planting approach -- is not to disturb the soil, or  do so as little as possible.

A good stab into the earth is a benign intervention. A good DEEP stab will also prepare the soil for the roots to follow.

A great idea when planting Daikon radish seedlings as in this image to the right.

Don't forget to recover your tent peg once the cardboard has settled over the earth and the seedling has taken off.

The tent peg will hold the cardboard in place as you pierce it to plant -- and later prevent any gust of wind from lifting the board and blowing it away.

In the plantation we also drop some manure into drilled holes -- so something akin to that may be an appropriate protocol in the kitchen garden as well.


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  • I do not put the cardboard  on the garden but was putting through shredder  and composting  but it wore out and now put in a container of water and pulp up and place where walk in garden  and eventually breaks down.

    If you can get Styrofoam boxs they are very useful   as if use as a planting container  kills the vegetation under or place inverted  on the ground  and will be left with bare ground after a few weeks and think the worms and insects remove vegetation in sheltered environment.

  • 8981306858?profile=RESIZE_710xI found that using my stabbing tool and the tent pegs, water flows toward the stabbed hole because it indents the cardboard as well as making a hole.

    Mind you, as my weapon suggests ( image at right) I'm a serious stabber.

    I could sign on as a mercenary with it or hunt ferals. Perhaps you have seen me in one of the Game of Thrones battle scenes? I'd also make a good Orc.

    I'm not throwing grass mulches on top initially, but there are mulches below the cardboard -- including  a green (living) mulch of scurvy weed.

    Like Sara Lee, my beds are layer upon layer of  mulch freebies going back years.


    I don't go outback without it. Serves 2 main functions:

    1. It stabs the earth to create planting holes
    2. it has a shaft just high enough for me to use to pull myself up from a kneeling position when down there planting. Very reliable for all that upping and downing and bobbing about.

    Unfortunately cardboard doesn't suppress all weeds as there are always weak spots, especially after some breakdown.Even plastic weed mat has a half life. But for annual seedlings it is a useful cover blanket to the soil.

    I always find that 'weeding' -- inasmuch as I can embrace the habit (it is not really my cup of tea) --  is nigh impossible around seedlings without dislodging the plants you seek to protect. Once there I defer to the survival of the fittest scenarios -- and this is why I appreciate the benign  invasiveness of Scurvy Weed. It's so very shallow rooted and pulls away with a light tug without uprooting other plant species.

    I started using cardboard on top of Scurvy Weed because the seedlings I plant get a longer window to do their verdant thing. I pull and drop the Scurvy weed. Lay cardboard on top and the rest, is as I say...

  • I use cardboard a lot as a base under mulch as weed suppressant (or at least slow down the onslaught...). I've found though -as Dave mentions below- planting into cardboard 'mulch' not ideal when watering seedlings. Basically, if you are a lazy waterer like me, or if you are relying on rain capture, the bit you need watered doesn't really get enough without targeted watering. Termites do love cardboard though so keep that in mind as you would with other termite food. We use rocks and bricks to hold the cardboard down on the edges until it sinks in. Cardboard is also great into the compost bin and under paths. Just be sure to not use that shiny cardboard with lots of inks - not all inks are garden/food friendly. You can save that to make recycled paper ;)

  • One complication with cardboard mulching is that if you use a thick board it won't easily collapse and bend to the soil contour after wetting. This can leave a gap between the cardboard and the earth. If you have snails or slugs they'll love  such easy-find accommodations.

    So if you think this may be a problem, stamp down the board and keep wetting it until it loses structure... or use more tent pegs to push it down. You can also soften the cardboard by piecing it all over so that the holes weaken its firmness.

    I've found that weighing down the board with rocks, bricks or pieces of wood isn't worth the effort as those loads protect the cardboard from the weather, obstruct water flow and slow cardboard breakdown while taking up planting space on the board's surface.

    I should also add that freshly laid cardboard isn't very permeable so water will tend to flow to the lowest point -- usually where the stab hole is located and the seedling is planted. This time of year -- when it can be so dry --think of dew run off.

    Even as it beaks down, the smooth edge of cardboard will direct water flow to its lowest point -- especially if the inundation is heavy. Very useful if you hand water your garden beds.

  • I found a different use for this wonder material as weed suppressing mat.  The narrow high part of the building site was infested with the inedible asparagus fern, wandering dew and a vine I call Cumberland's Curse.  Whilst I got the most of it, I was dead concerned it would come back.  So, I drowned it in cardboard.  Now, I'm not actually planting in the soil so I covered it with lots of straw and did not poke holes in.  I am putting 100 liter grow bags on top to plant in.  Eventually, the cardboard and straw will breakdown and help build the soil. Hopefully, I will have smothered the life out of any bits of weed under it first.  

  •  I really am impressed with idea Dave and if we hadn't planted out our vegies on Saturday I would have used it, but next time I will. I really can see the potential of using the cardboard. 

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