Weeds, the bane of any gardener or farmers growing season. There are several different mitigation plans you can utilize from weed killers to old fashioned hand pulling, but if you can stop them from coming up from the start that will cut down on needing to use any of the other options. That is where silage tarps come in as a great option for those wanting to cut down on extra labor, later on.

Tarps, also known in agriculture as “silage tarps”, are one of the most underestimated tools for small farms and gardens. It may seem like a overly simple piece of plastic but, using tarps can really lead to dramatic gains in efficiency while improving soil health. Their immediate and rapid action aligns perfectly with the intensive nature of small-scale farming and large scale gardening. When considering how to manage weeds, using tarps is a game-changer. Plus, they are a clever way to incorporate green manure without tilling and can accelerate your bed preparation.

What is a Silage Tarp?

Composed of UV-treated Polyethylene plastic, silage tarps can be used to cover the soil to reduce weed pressure and to help prepare the soil before planting. They are black on both sides and can be bought in any store that sells agricultural supplies or equipment. They are used to cover up silage in dairy operations (hence their name: silage tarps). They are durable and as long as they are well-maintained, they can be reused year after year.

Now, while that might sound like you can utilize the basic black tarp you might get for covering a load in a truck as it is cheaper, please take note of how things break down. Silage tarps are built and treated to be out in the sun and weather much more so than your standard tarp is and while costing more initially will not need to be replaced nearly as often or start to fray as a standard tarp would when used in the same manner. So, if you are going to utilize these in your garden it will be best to use the right kind of tarp so that you save money and waste in the long run.

How does it help with weeds?

Silage tarps are a smothering style of dealing with weeds, also known as occultation. The term, derived from the verb “occult”, means to “cut off view” which really sums it up: by cutting off the light from reaching the soil, you deprive weeds of light. Weed seeds germinate under the tarp and then die because they cannot photosynthesize.

To achieve this, you can use 6 mil (thousandth of an inch) opaque black tarps that is placed on your seedbeds. Then left for long periods, at least a minimum of two weeks in the summer and a minimum of three weeks for the other seasons– the tarps create warm, humid conditions in which weed seeds germinate. However, due to the absence of light and air movement, the young weeds are killed quickly. By covering the beds with tarps, you can deplete the energy supply of certain invasive weeds and in time, this gets rid of the problem.

If you have beds that aren’t going to be cultivated immediately, you can also use tarps to cover them at different periods during the growing season. For example, if you use a bed to grow early carrots in the spring and then use the same bed in the fall to grow squash, there will be a few weeks during that period where the bed will be unused. To avoid an invasion of weeds, after harvesting the carrots, you will place a large black tarp over the bed and leave it there until you are ready to plant the squash. Once you’re ready to lift the tarps, you will quickly see the benefits of how they diminish weed pressure on subsequent crops.

How do silage tarps help with green manure?

Tarps are also a great way to effectively incorporate green manure into your beds while maintaining the quality and biodiversity of your soil. They fit well into a minimum-till cropping system because they allow green manure to be incorporated into the soil without tilling it. Simply pass the flail mower over the green manure (as one would do with crop residues) and then place the tarp over the beds. This practice speeds up the decomposition of the green manure by creating ideal conditions to stimulate the activity of the soil microorganisms. Hence, tarps are essential for a diverse market garden with fast crop successions.

Starting the growing season early with Silage Tarps

For Alaskan gardeners one of the largest benefits of using a silage tarp is the season extension option as we look to grow more with less. This is a method that needs to be implemented during you fall clean up and winterization garden prep.

Covering your gardens with tarps in the fall also reduces the time needed to prepare your beds in the following spring. Thanks to the protection of the tarp, there will be less water accumulated in the soil. As soon as temperatures warm up, remove the tarps and you’ll be ready for cultivation and planting much quicker!

Really, the only challenges that can be seen are that they are not easy to move around. To overcome this, all you need is enough tarps to have 2 per 10 (100’) bed garden – then you won’t have to carry many at one time. If this works for you, then find some tarps to support your minimal tillage system and watch the benefits unfold!