Q. I am in the process of buying a property with 5 acres where I will keep my three horses. I’d like to offer them grazing year-round. It’s not particularly cold here in California, but the winters are wet. What can I do to help ensure they have viable grazing available throughout the year?
A. Congratulations on the purchase of your own horse property! I would encourage you to seek out and read a number of the resources available online for managing horses on small acreage. I grew up keeping horses on pasture year-round in a wet climate. It can be done but takes careful management and an understanding of how grass grows, as well as the optimum grazing conditions.
Grass Plant Growth
Unless you are somewhere with a very mild or hot climate, such as Southern California and Florida, most pasture grasses are cold-season, meaning spring and fall are their main growing seasons. Their growth slows in the summer, and they might go dormant for as long as four months in the winter even though they remain green.
Grasses generate energy through photosynthesis in their leaves. The resulting carbohydrate is taken and stored in the roots. The roots capture oxygen and water from the soil and, combined with the energy from photosynthesis, support leaf and stem growth. A healthy grass plant therefore has abundant and deep roots equal in size or greater than the amount of plant you see above the ground surface.
However, if horses graze grasses too short the plant will not have enough leaf material remaining to create adequate energy through photosynthesis to support it. In this situation the plant will draw on root reserves to grow. If grazing continues, the root reserve will become depleted and the amount of root may be less than the amount of plant material above the soil surface. Grasses in this state start to die, are easy to pull out, and get outcompeted by weeds. The result is an overgrazed pasture with bare ground between grass plants and possibly weeds. You can avoid this with good management, but it requires resting pastures once most of the grass is below 3 to 4 inches.
Horses are selective grazers, meaning given the choice they will typically choose to eat the shorter (and sweeter) pasture grass. This means horses will graze the same grass areas over and over while rarely consuming other areas of the pasture. At a glance it might look as though the pasture still has plenty of grass, when in reality it doesn’t.
Ideally, you should mow resting pastures to essentially “graze” areas of long grass and ensure they start their regrowth at fairly uniform height. You should also harrow resting pastures or have manure removed to reduce stale areas (horses typically do not eat where they defecate or urinate), as these will also result in long, unappetizing grass.
Horses shouldn’t graze on a rested pasture until most of the grass has reached a height of 6 to 8 inches. This allows the plant to replenish energy stores in its roots and grow enough for grazing to occur without damaging the grass.
Because of this need to rest pastures, you should look at your property and determine how many pastures you will need to have enough pasture to graze while resting others. The number of pastures and their sizes might also depend on whether your horses get along well enough to graze together or whether they need to graze alone.
You might achieve more uniform grazing with several smaller pastures than fewer larger ones. Smaller pastures increase stocking density and help force the horses to eat all the grass and be less selective in what they will eat. In this scenario, horses likely do a better job of using all the forage in the pasture.
How long it takes a pasture to regrow depends on the time of year. During the active growing seasons regrowth to 6 or 8 inches might only take a couple of weeks. However, in slower growing periods it might take more than a month. This is something you need to consider when determining how many pastures to create.
You might not be able to create enough pastures to house your horses while also allowing adequate rest periods. In this case you will need a sacrifice area, which is either maintained as dirt or covered with a weather- and wind-proof footing such as gravel, decomposed granite, etc.
A sacrifice area is a great idea, even if you do have the ability to provide your pastures with ample rest.
A sacrifice area also gives you a space to turn out horses should you need to keep them off pasture to manage their body weight. Additionally, when the ground is very wet it is best to keep horses off all pasture, because walking on wet grass not only damages the turf but also compacts the ground. If you can make an impression while walking across a pasture it’s too wet to turn horses out on.
Pay attention to how water drains on your new property and plan accordingly. Position high-traffic areas such as gates, shelters, troughs, and feeders where the ground is least likely to become muddy. For safety, use permanent fencing to enclose the perimeter; however, consider initially using internal temporary fencing, such as electric tape, so you can move it and experiment with potential pasture layouts before committing to permanent structures.
With a little knowledge of how pastures grow, how horses like to eat, the type of soil you have, and a well-planned sacrifice area, you can successfully provide your horses with a quality source of pasture to help meet their nutritional as well as behavioral and psychological needs.