No-Till Alternatives to Silage Tarps
After this week’s article about how “we really need to talk about” the potential toxicity of pthalates, a lot of people we’re asking for alternatives to the polyethylene tarps. And our suggestions may not be what you expect...
It is important, however, to start by asking ourselves what tarps do for us and what we hope to achieve by using them.
First, growers use tarps for a few very specific reasons: when we’re starting a new garden, when flipping whole plots, to terminate cover crops, for cleaning up cultivation mistakes (slowly raises hand), and for keeping a plot ready to plant so nothing grows there and it doesn’t erode (see the contradiction).
The net effect of tarping (or occultation, if you’re feeling fancy) is that it helps germinate some weed seeds, cleans up crop residue, and basically offers you a ready-to-go garden with minimal effort and minimal tillage. Conversely, it may cause some compaction and anaerobic issues. And if they are polluting the soil—which, again, we need more testing (I am actually contacting labs as I write)—and will inevitably pollute the environment, then what can we use in their stead?
Two Different Polys
There is a difference between polyethylene and polypropylene. The woven polypropylene tarps are, to my understanding, less likely to contain the pollutants like phthalates (pronounce “thal-ates” or more fun “f-thal-ates”). Though the microplastic—eventually nano-plastic—issue still exists, this could be a simple alternative. Heavier and generally more expensive, but an easy option.
Assuming you want to get away from tarps entirely, you can simply plow and form your permanent beds however you intend. We have talked about this a number of times, but tillage may—for those low in organic matter or rich in clay—be a good overall approach if done properly. Add good compost, good organic matter, all the minerals you need, then till. Sure, you’ll have to stay on top of the weeds during the first few seasons, but eventually the weed pressure will decline.
You also have the option of mowing intensively, adding thick cardboard or paper mulch, then covering with thick compost and woodchips in the paths (see Richard Perkins for great advice on this).
This is where it gets more tricky and/or labor intensive. We have a whole plot of garlic coming out right now. What do I do about the residual weeds that are thrilled about the newfound sunlight?
Using our farm for an example, the weedwhacker bed flip is an option, but we’re talking ten 100ft beds, so that’s not a small job. Also, we can pull the weeds as we pull the garlic, but we will definitely miss some. We could cultivate out any weeds we miss and expect a little cultivation to come, but the plot should probably be planted immediately. Our plan right now is the pull weeds, lightly cultivate, and plant immediately to a cover crop before fall carrots. Why not build a little soil in the interim? Which leads us to…
Terminating Cover Crops
Tarps are amazing at terminating cover crops. Truly a game changer for no-till growers to be able to throw a tarp over a cover crop and have it do all the work. But what other options are there? There is always rolling and crimping, but that is tough on a small scale and timing has to be damn-near perfect. You could mow the cover and immediately transplant, but in beds where carrots are the end goal—dense direct seeding—what then? A tight mowing of the right cover crops (Sudangrass will grow back, for instance, buckwheat will not), may be a good place to start. Then, direct seed and flame weed in five days (this is what I will likely do,I’ll keep y’all posted). But, if the mulch is desired, what about pressing it down—maybe a la Frith Farm or with a roller of some sort—then flaming it immediately to kill the tender stems? I have also thought about the weedwhacker/schythe option for terminating it at the base, then raking it aside into the paths and seeding. That may be a little messier and labor-intensive overall, but an option none-the-less.
It’s easy to see how complicated and nuanced dealing with cover crops in a no-till system can be, especially without the use of tarps, but we think cover crops perform important functions for the soil, enough so to keep working on methods of incorporating them into the small-scale, no-till, hypen-friendly, market-garden effiiciently and effectively.
One could also mow, cover with cardboard or something organic, then more compost, but that is an expensive proposition to do year after year and one we don’t recommend. A bed should ideally be set up one time and then amended as needed. Setting up a new bed after every flip would not likely be profitable.
Something Conor Crickmore has done a great job of highlighting is that a tarp is, at best, a placeholder. If you need a placeholder, you may be farming too much land, or not farming it well enough. Your placeholder should, within reason, always be plants. “Keep it planted as much as possible” is a critical no-till principle for maximizing photosynthesis. If you screw up a plot it’s a sign of bad management (I point the finger at myself here, too).
Although tarps can help correct mistakes, they should not be relied upon. I believe it would not be the worst thing for my farm to simply remove the option entirely and learn to farm better. Will I get into a pickle from time to time? For sure. Will I continue to repeat the same mistakes without the big polyethylene eraser? That is far less likely.
What about hay and straw?
If you can get weed free hay and straw then go nuts. If you can’t, then you may end up with the same issues you are trying to cover up. I like straw (I’m calling about some today), but it has to be seed free.
What are some of the methods you’re employing to reduce your reliance on tarps? Let us know int he growers community.
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