Many people ask me about mulch, and mulch is really a very broad topic. There's a lot of different kind of mulches. There's wood mulch, there's even rubber mulch. You could use stone as a mulch, you can straw as a mulch. Mulch just means a top layer of some kind of matter, organic or inorganic, that's going to protect the soil, keep the moisture in, and keep the sun from hitting the soil so that weeds don't sprout. A very common mulch that many people use is a hardwood mulch, say a cedar mulch. A lot of people like that because it breaks down very slowly and it looks attractive. It's less likely to feed the soil though than if you use something a little bit more organic. We like to use raw wood chips, although not too many, because they're free. We get them when we cut down a tree and we shred the branches and then rather than take that to the dump, we use it as mulch and it feeds the soil slowly as well as inhibits weeds. Now, when you're mulching a tree one of the keys that you want to make sure is that you don't get the mulch up too close to the trunk of the tree because if you pile the mulch up around the tree bark small animals like voles can come in and strip the bark off of the base of the tree. It also invites a place for insects to work their way into the tree.
So what you want is say one to three inches of mulch, probably two is an ideal number, around a circle around the tree. You want to leave the area just by the tree trunk free so that that has plenty of air circulation and it doesn't give small animals and insects a chance to get at your tree root. So Hal is going to demonstrate now how to mulch a tree.
So now we have a nice thick layer of mulch around the tree that's going to keep the moisture in the soil and prevent weeds from sprouting. You'll notice that it does not touch the tree trunk. That's the ideal there. And let this mulch sort of decompose a little bit before you add more. Some people go out year after year, keep topping off the old mulch until the end up with something we call "mulch volcanoes" that are sort of inclined up against the tree. That's really bad for the tree and it's unnecessary. One final word: mulch and compost are not the same thing. Some people are confused. Compost is organic material that is already broken down and will feed the soil. Mulch is something that either will not break down or will break down slowly and feed the soil later, but it is in a raw state now. So use mulch where you want mulch. If you want to feed the soil use compost or a material that's already broken down. And that's my tips for mulching.