How to Hold Silage Tarps Down
February 1, 2024
As a follow-up to my post on How to Use Silage Tarps to Kill Weeds, I want to go over how we prevent our silage tarps from blowing away in the wind. I’ll also share some hard-learned lessons about using silage tarps on the farm as a no-till approach to soil preparation.
If you want to get into Silage Tarping to kill weeds and prep planting beds on your farm, you’ll need to first make sure you’re using the correct kind of tarp and that it is made of thick, high quality plastic. Silage tarps are non-permeable plastic and do not allow any water through, unlike Landscape Fabric (also a great tool to keep weeds down on the farm, but we use landscape fabric for different reasons - read about our Pros and Cons of using landscape fabric here).
High-quality Silage Tarps can be purchased easily on Amazon from the Farm Plastic Supply Co Store.
I recommend the following two silage tarps, depending on the size you need:
challenges of using silage tarps on the farm
The biggest challenges of using Silage Tarps on our farm have been the following. I will spend the rest of this post discussing the points below. I hope you find my experiences helpful for planning your own silage tarping adventure.
Holding the tarps down in 60-mph winter winds (it took us a few bad experiences to figure out what works best)
Moving the tarps around (big tarps are extremely heavy, which is why I recommend using no larger than 20’x100’ Tarp for two people)
Moving concrete blocks around when moving the tarps (we use concrete blocks to hold our silage tarps down… more on that below)
Storing silage tarps when not in use (they take up a ton of space in storage and are a pain to fold up after being covered in stinky water and soil, so we’ve decided its best to just keep moving them around to different parts of the field with a cover cropping rotation)
Preventing punctures/holes in the tarps
Accepting that voles love living under the tarps and there’s no changing that
how to hold silage tarps down
The biggest question I asked myself before even buying a silage tarp was, What am I going to use to hold these silage tarps down in crazy winter winds? It seems that most farmers like us, who are using silage tarps as a form of organic weed control, use Sandbags to hold their silage tarps down. I understand why Sandbags are an obvious choice — sand is heavy, filled sandbags aren’t that hard to move around, sandbags are UV-treated so they last a few years, and they’re just generally what people suggest to hold anything down. If you are going to use Sandbags, I suggest Sandbaggy as a good brand — I’ve bought them for other needs.
Related: How to Plant Clover Pathways
I am a contrarian at heart, and I knew sandbags weren’t going to work for my silage tarping system. No way was I going to have a load of sand dumped on my property, then spend a ton of time and energy filling the sandbags only for them to eventually deteriorate in the sun after 5+ years of exposure. That didn’t seem effective for cost, time or resources — essentially, sandbags didn’t fit into my lean farming goals.
It’s important to note here that using soil from your farm or garden isn’t best practice for filling sandbags, for multiple reasons. First, digging up soil and moving it out of a growing space or open land is an active form of soil erosion. Second, soil is not as heavy as sand and won’t do a good enough job keeping the sandbags down anyway.
I decided that using concrete blocks would be the best option for holding the silage tarps down. Concrete blocks are heavy enough, generally easy to move around (we throw them in the bucket of our tractor to move 12 at a time), they won’t break down, they’re useful for many other things, concrete blocks are reusable, and most of all, they come ready-to-use and don’t require filling with sand.
Related: How to DIY a Seed Starting Setup
I ordered concrete blocks for delivery from my local Home Depot. Delivery cost $80 flat fee, which I was more than happy to pay because I don’t have a pickup truck to move the blocks from the store myself. When Home Depot delivers, they have a skid loader that they can drive to wherever you need the blocks dumped on your property. It was so convenient!
using concrete blocks to hold silage tarps down
When using concrete blocks to hold your tarps down, it’s important to order big, heavy blocks. I started out thinking the 16 pound half-blocks would do the trick. Boy was I wrong. You must buy the full size concrete blocks to hold silage tarps down, no matter the size of the tarp. You also need full-sized blocks for holding down landscape fabric. I ended up buying these exact 33 pound concrete blocks and they work amazingly for holding my silage tarps down in even the most menacing wind storms.
How many concrete blocks do you need to hold silage tarps down? We space our blocks 4 feet apart, around the entire perimeter of the silage tarp. If the silage tarp spans more than 20 feet in one direction, we will also add a row of blocks down the middle of the tarp.
will heavy stones hold a silage tarp down?
If you have heavy stones or rocks on your property, you could use them to hold your tarp down if they are heavy enough. Remember how I underestimated the amount of weight that would be needed to hold a silage tarp down in the middle of a wind storm. Your rocks must weigh a minimum of 30 pounds (35+ is better) to be used to hold your tarps in place.
Related: How to Fix Soil After Using Chemical Fertilizers
how to move a heavy silage tarp covered in rainwater
The biggest challenge with moving silage tarps is that they become covered with rainwater (and snowmelt, in the winter). The water on top of the tarp is heavier than you could ever imagine. When there is ample water on your tarp, you will need a willing, gracious crew to help you dump the water off the tarp so it can be moved.
The best way to deal with a silage tarp that is full of water is to just work methodically and slowly, with three to four people. Start on one end of the tarp and have each person stand in a different spot along the edge. Work together to pull the tarp up and try to move the water to a low spot where you want it to drain, preferably off your planting beds. If your planting beds become sopping wet with water, you won’t be able to prep your soil and plant right away. Building permanent raised beds helps with drainage.
If you are working with a huge silage tarp (spanning more than 50 feet in one or both directions), you may actually need to poke holes in the tarp or cut the tarp in half with scissors in order to drain the water. In the wet seasons, the amount of water a silage tarp can hold should not be underestimated!
Related: Why is Tilling So Bad?
Moving a silage tarp covered in water — perennial weeds were not entirely killed
Water from silage tarp flooding the field. I had to puncture holes in this tarp to drain the water out.
how long do silage tarps last?
Silage tarps are made of UV-protected plastic, but as anything that is exposed to harsh outdoor elements, they will not last forever. With good care, it is said that silage tarps will last at least 5 seasons (I have been using mine for 3 seasons, so if/when they last longer than 5 seasons I will update this).
how to prevent holes in silage tarps
You can take better care of your silage tarps by preventing punctures. I have learned the hard way that sharp weeds that are growing out of the ground will actually punch holes in the tarps. For instance, if you mow old brush/weedy areas before laying tarps, there will be many dead sticks (which are actually dead weeds) poking out of the ground. Those dead weeds will absolutely poke holes in your tarp. I’ve prevented this from happening by pulling out the biggest dead weeds/sticks by hand before laying the tarp down. Yes, it is a lot of work, but that extra effort is worth it because silage tarps are expensive, not to mention they are a petroleum-based product that we don’t want to have to replace every year due to negative carbon impact.
Related: Organic Fertilizers for Flower Farming
It goes without saying that if you toss your rocks or concrete blocks onto the tarp, you are more likely to puncture the tarp. So don’t throw the blocks — set them down gently. Likewise, stepping on top of your silage tarp when it is lying on the ground will also cause sticks and sharp rocks to poke through it.
Lastly, voles will eat holes in your silage tarps if you store them folded up in an area where rodents have access. You should store your silage tarps above ground on a shelf where voles and mice cannot climb up and build nests inside. I’ve also had voles eat holes in my silage tarps out in the field, but this only happens if you have your silage tarp folded onto itself while tarping a smaller area.
Holes in silage tarps can be repaired with this Waterproof, UV Black Duct Tape.
You can also tamp large weeds down using a long wooden board. My farm helper, Jess, and I did this in an overgrown weedy patch before throwing a silage tarp on it. Tamping the weeds down prevented the weeds from puncturing the tarp. See how we did this below.
Tamping overgrown weeds down with a wooden board before silage tarping
dealing with voles under silage tarps
If you have voles on your farm like I do, they will gravitate toward living underneath any landscape fabric or silage tarps that you have out on your field. Silage tarps keep voles protected and warm over the winter, and also protect them from predator birds. I have had so many issues with voles eating my crops that I’m finally throwing my hands up and not caring anymore if they live under the silage tarps. In order to keep their populations down, I would recommend using simple snap traps around the edges of the silage tarp — but you will have to check these daily for dead voles, so I personally don’t do this because I don’t have the time to spend.
Related: Outsourcing Compost and the Risks Involved
Once you pull the silage tarps up, the voles will scatter for another protected place to live. They could scatter to a neighboring silage tarp, landscape fabric, or they could run directly to your crops where you definitely don’t want them making new nests. I have lots of thoughts on dealing with voles on the farm, and once I write a post on that I will link it here.
I hope my experiences with silage tarps have been helpful for you! I certainly love using them for an organic way to control weeds on the farm. Definitely read my post about Using Silage Tarps to Kill Weeds if you haven’t already.
peace, love, and concrete for the win,
Fran Parrish
