Supplement mulch with nitrogen

: After watching a video of orchards and the use of mulch around the base of the trees, I am considering ordering an electric chipper to deal with my tree and shrub trimmings. But, the chipper isn't cheap and I have heard that you should not use tree trimmings for mulch because the decomposition consumes nitrogen that would otherwise be used by the mulched plants. Any suggestions? Should I compost it first?

A: Decomposing mulch will consume nitrogen but it is nothing to be overly concerned about. You just add a little bit of nitrogen to the decomposing mulch either in the form of compost or agricultural fertilizers. You also can use the smaller chippings as the carbon source for your own compost.

Research your chipper carefully. I doubt that an electric chipper can do 2-inch limbs, but smaller stuff to about an inch will probably work. You will need to maintain it by keeping the blades sharp.

Maybe you can help your neighbors out if they are like-minded. Creating your own mulch and using it will be a cost savings to you in fertilizer and water, as well as reducing your work load and getting your plants to perform better.

Bob Morris is an associate professor with the University of Nevada Cooperative Extension. Direct gardening questions to the master gardener hot line at 257-5555 or contact Morris by e-mail at