Can I use that Silt in my ditch?
We’re thinking of adding the silt from our irrigation ditch into our raised planters. Is this good to use? Should we add some compost to it? How much should we add, or will this even work?
You have to be a little careful using that sediment. It can sometimes be very salty which is a bad thing. If you have piles of it from a past year and there’s a white crust on it, it’s probably better to pass on it.
If you want to be sure, take a sample out to the CSU Extension office, and they can do a salt test for you.
There are times when it isn’t all that bad of a soil. There’s a good amount of organic matter in it, and the texture is usually pretty good, though there are times when it has a lot of clay, which isn’t all that helpful.
The mineral part of soil is made up of three different particles: sand, silt and clay. The difference between them is size. Sand is the coarsest, clay the finest and silt in between. A “perfect” or “loam” soil has a nice balance of all three.
Our native soils tend toward clays, which make them poor draining and poorly aerated. The sediment in the bottom of the ditch is usually sandy and/or silty since the clay tends to wash away in the water.
You can get a rough idea what is in that sediment by moistening it to make mud and rubbing it between your thumb and fingers. If it’s gritty, there’s a good amount of sand in it (that’s good). If it’s smooth and “buttery” there’s a good amount of silt in it, (also good) but if it’s sticky then it’s clay and you’ll need to add more compost to the soil.
If your sediment isn’t salty, then adding some compost to the sediment would be a good idea. I generally like to add one part organic matter by volume to two or three parts soil. If the sediment seems heavy with clay, you may consider even going one part organic to one part soil to lighten it up.