how often to mow horse pasture

Asked June 4, 2016, 1:38 PM EDT

you guys have been great answering questions about my horse pasture in Twisp. Here is another one: I have 5 irrigated acres and am grazing 3 horses. no cross fencing or rotation. it is all going well and they are eating most of it but just for pasture health shouldn't i mow and rehab parts of it? how many times per growing season should I mow it? in other parts of the state i mowed maybe once or twice per year but we lived on the west side with tons of rain then summer drought so i don't know how to handle an irrigated pasture. i'm just think for pasture health and weeds and all it should be mowed at least once. what kind of strategy would you suggest? i really don't want to get into many rotating sections but i could maybe cut it in half and mow half and let that rehab. they are not overgrazing it at all , if anything they aren't quite keeping up. let me know.

Okanogan County Washington

1 Response

Hi – you are either “over-landed” or “under-horsed,” which are nice problems to have! This situation is quite rare for horse owners. Rotational grazing is always the best practice for long-term plant and animal health. When you allow horses access to all areas of a field, they keep grazing (overgrazing) their favorite part. They eventually kill those desirable plants and undesirable plants (turf grasses and weeds) come in. If you can divide your pastures into 5 separate paddocks (one acre each) and rotate the horses through them, you will see much better plant vigor and health. Also, rotation will help you reduce the number of parasite larvae the horses are ingesting. Do you have any interest in making hay on this area? If so, you could fence off 2 to 4 acres and let that grow up to haying size. It may be difficult to find someone willing to make hay for a reasonable price on such small acreage, though.

Mowing is needed when animals can’t keep up with plant growth. Plants “want” to grow to maturity, set seed, and shut down for the season. We want them to stay vegetative because that form is more nutritious (more protein and digestible fiber). We keep them vegetative by mowing before they head out. I can’t tell you how often you need to do this—it will depend on your irrigation and the weather. You can easily assess by taking a look, though. In most cases, you would mow or graze when grass plants are 6-8” tall and only mow/graze down to 3” (take half, leave half). The plant’s energy reserves are stored in the bottom 3” of the stem, not the roots, so overgrazing really sets plants back. Grass plants respond to grazing/mowing by sending out more tillers (stems) and making the pasture thicker, capturing more sunlight and making the field more productive. Mowing will also stimulate new and more palatable growth on the plants the horses don’t tend to eat and it will help control weeds if you mow before they set seed. Harrowing the pasture is a good idea, too—it distributes manure (fertilizer) more evenly and reduces the taboo areas where horses refuse to graze.

Yes, it would help to divide your pasture into at least half; the more sections the better! A forage and pasture specialist in our state recommends 365 separate paddocks—a semi-joke, but it helps get the point across.

Have you considered putting more animals on your property to make use of all the grass? You could finish some steers or lambs or lease out a few acres to a neighbor who wants to do so. You could also board a few horses for added income if you so desire. You’d have to take care introducing new horses to your horses, though; contact your veterinarian for advice on how to do so.

Best wishes,