
Using grass clippings for mulch deals with a common dilemma for the modern gardener. The lawn is pretty, nice to walk on, but it’s not my favorite part of the yard to care for, yet, if I don’t do something about those dandelions, they will infest my vegetable and flower gardens. If I don’t mow and edge the lawn, it will go to seed in my garden or spread via roots. Grass is a pernicious invader. Fortunately, the southwest Idaho climate makes using grass clippings for mulch an undemanding exercise.
We have tried just leaving the mowed grass on the lawn, but we probably always wait too long to mow (who has time to mow every 4-5 days?), so it clumps in piles. This kills the grass attempting to grow underneath, leaving us with dreaded “spotted lawn.” Since mulch is so useful, I have chosen to designate the lawn “a mulch factory.” Here are the simple steps to using what it produces:
- Dump your grass clippings throughout the garden while in the middle of mowing. It saves you the trouble of bagging it.
- Go back within 24 hours and spread the clippings to a depth of 1-2 inches. In Idaho, they will generally be dry in a day or two, even if you have overhead sprinklers in your garden.
- If you don’t get to spreading it right away, it will begin to mold and stink and remind you… however, I go ahead and spread it then, too.
- Repeat as often as you like, as long as the first layer has dried!
The clippings in my yard have always decomposed without me taking extra measures, usually within a year. If the layers have been spread too thick for the topmost to decompose, that top layer helps with weeding by creating a sort of net which can then help with removing the first spring weeds and winter debris.
I know there is some concern about decomposing grass clippings depleting the soil of nutrients for the growing plants, but I haven’t found this to be a problem. In fact, the garden beds that have primarily had grass clippings for mulch have had unexpected soil improvement. The only mixing and turning of the soil with the clippings, or decomposed clippings, was when weeding was done. I gave up rototilling a few years ago. I do use other compost, too, but not necessarily over the whole garden. It’s hard for me to get the whole acre thoroughly covered with any one thing –

In addition to retaining and supplying moisture, and aiding with weed control, the dry grass clippings help protect ripening produce from rotting or getting eaten by bugs that inhabit the ground. The dry clippings provide a soft, airy layer for things like tomatoes and peppers to rest on. For some reason, the insects are not inclined to crawl up through the layer.
Do not use grass clippings if the grass has been recently treated for weeds. Your garden plants are in the weed category for lawns. I wait 2-3 weeks, which means I usually do have some clippings to bag until the waiting period is over. Maybe I can figure out a way to mow in time to at least leave these clippings on the lawn, to get the most from the treatment. If you don’t treat your lawn for weeds, you may be inadvertently planting weeds in your garden beds.
Grass clippings may not be the first choice mulch for your showplace flower garden that can be seen from the street, but even there, grass clippings can be spread, then covered with another mulch after they dry. Make good use of all that nitrogen that is being stored in the grass! Let the kids use your mulch factory to play soccer on, having the peace of mind that comes from knowing it is working for you at the same time!
