Using Paper Mulch to Suppress Weeds in the High Tunnel

March 26, 2025

These days, we’re all looking for more ecological ways to suppress weeds in our farms and gardens. Weeds are, undeniably, one of the biggest problems that chemical-free growers face, especially on plots like ours. Our 1-acre flower field was previously a meadow full of invasive (and non-invasive) perennial weeds with relentless root systems. This means we spend a lot of time not only physically battling the weeds but also planning how to prevent future weeds from spreading.

There are a myriad of ways we sustainable growers manage weeds without chemicals, including: hoeing and hand pulling, using landscape fabric, strip tilling, flame weeding, using silage tarps, sheet mulching and deep mulching, to name a few methods. One other weed control method I was cautiously optimistic about using in our high tunnel last year was paper mulch.

In this post, I will discuss my experience using paper mulch to successfully suppress weeds in our high tunnel beds, along with using cardboard to suppress weeds in the paths. Paper mulch, it turns out, works incredibly well in covered growing spaces and I’m excited to report on the results!

soil prep and bed layout in the new high tunnel

In late 2023, we constructed a 96’ x 30’ high tunnel (or, rather, I hired a local Amish crew to build it for me, and they got it done in just three days. Sometimes paying other, more skilled people to do hard things can be very wise!)

In Spring 2024, we began soil prep and bed layout in the tunnel. Initially, the ground inside the tunnel was covered in thick perennial grass and cover crops so we decided to do an initial till with the tractor. Before tilling, we threw bags of leaves, that had been collected in the fall, onto the soil to be mixed in. Since we are a low-till farm, this was the first and last time the soil in the high tunnel will ever be tilled.

Tilling cover crops in the high tunnel. This will be the only time this soil is tilled.

After tilling, we dug the pathways and broadforked the beds.

After tilling, my partner, Jesse, and I dug the pathways 2-3 inches deep and added the excess soil to the planting beds, which raised the beds up, similar to the permanent raised beds in our field. Our 30-ft-wide high tunnel has (6) 30- to 36-inch beds with 24-inch paths in between the beds and a 24-inch pathway border around the sides and back edge of the tunnel. The front 12 feet of the tunnel (part of which is shown as cardboard in the above photo) is an open space that we use to store tools and supplies, and it is an area where we can sit and have lunch on rainy days.

After digging beds, we used a broadfork to help break up the hardpan clay layers of soil underneath the tilled layer.

Using cardboard mulch in pathways

A few of the most obvious ways to suppress weeds in a high tunnel are using landscape fabric or organic mulches such as wood chips or straw. Since I have a never ending supply of cardboard (I can get free cardboard anytime from my florist friends), I decided to line the pathways with cardboard before covering them with wood chips (which I also get for free from a local arborist). This method did a superb job of keeping weeds down while the cardboard added an extra-effective layer of weed suppression. I will continue to manage pathways in the tunnel this way until something better comes along… though I’m not sure anything better will!

As our pile of wood chips has dwindled, I’ve resorted to buying bags of poultry bedding, which are pine wood shavings (lightweight wood chips), to fill in the paths where the wood chip mulch has started to break down. I’m hoping we will get another free wood chip dump this year to avoid having to buy bagged mulch, which is a much less sustainable option.

Here, you can see some beds with paper mulch and pathways with cardboard and wood chips.

Using paper mulch on planting beds

I decided to use paper mulch (this exact roll of paper) on three beds in the tunnel last year. The photos below show the permanent eucalyptus bed being planted using paper mulch. Here, I rolled the paper out onto the bed, poked holes into the paper and planted using a dibber (my favorite planting tool!), then covered the paper with a thick layer of wood chips. Irrigation drip lines run on top of the wood chips.

Planting eucalyptus into paper mulch.

A dibber works great to poke holes and plant into paper mulch.

This is the paper mulch I use — it is a contractor paper. Paper rolls sold as garden mulch will always cost more:

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In two other rows, where I planted tomatoes, marigolds, and celosia, I laid the paper mulch on top of the soil then covered it with a 1-2” layer of compost. Adding soil, compost or wood chips on top of the paper is necessary to keep it in place during wind storms. This is necessary even in a high tunnel — the sides are open on most days and it can be quite windy in there.

Permanent eucalyptus bed covered with wood chips.

Annual plantings are planted with paper mulch then covered with compost. Marigold bed on the right.

Does paper mulch work to keep weeds down?

I was completely stunned that in the tomato, marigold and celosia beds, hardly a single weed had grown through the paper mulch all summer. I only had to hand weed those beds once, in the planting holes around the transplants as they were getting established. The paper did the most amazing job of keeping weeds down and I will never plant without it again! Meanwhile, in the dahlia bed where I did not use paper mulch, the weeds had to be managed consistently using hoes and hand pulling.

The marigolds have grown splendidly in the paper mulch. To the left, the pathway was not mulched with cardboard.

A ground beetle’s eye view shows absolutely no weeds growing in the marigold bed.

Does paper mulch work outside in the field?

Paper mulch works so well in the high tunnel because the growing space is protected from rain. In covered growing spaces, rain is not able to constantly wet the paper and degrade it. As such, in the uncovered field, paper is not as effective — I’ve tried using it in the field with dismal results. Alternatively, you could try using this thicker card stock paper roll, which will be a bit trickier to plant into, but will hold up longer.

Cardboard works well in uncovered fields open to the elements, especially when it’s used to mulch around established perennials. Cardboard can also be used as a sheet mulch in the fall by layering cardboard on top of the planting bed, then adding compost on top of the cardboard, and letting it break down in place over winter. By spring, you’ll have a lovely, cushy, weed-free patch of earth to plant in.

Corrugated cardboard rolls can be purchased, but I encourage you to source used cardboard instead of buying new. Cardboard is ubiquitous and flower shops are always happy to get rid of it.

What happens to paper mulch when the season ends

The beautiful thing about paper mulches and cardboard is that they are biodegradable and can be left in place. This is another reason why using paper mulches is so great — it takes less work because you don’t have to remove them, and they add organic matter to the soil that microbes and earthworms will enjoy decomposing.

I hope this shed some light on your questions about paper mulch! It’s 100% worth using in the covered growing space. The cost of the paper mulch is WELL worth the cost of labor spent on weeding. I’ll be suppressing weeds with paper mulch and cardboard probably forever!

peace, love, and compassionately controlled weeds.

Fran Parrish