Successfully converting a wooded area into a pasture requires a lot of planning and decision making. Such a conversion can be pretty expensive, and so it is best to do it correctly the first time. Successfully established pasture areas will have high quality grass, strong perimeter fences, cross fences, sunshine with some areas of shade for the horses, water, and an unrestricted flow of fresh air. If possible, the area should be large enough to accommodate normal ‘horsing-around’ activities.
Planning for Your Pasture
The first step in the conversion process is to identify areas on your property with the potential to support high-quality pasture. Look for areas with gentle slopes to reduce the potential for erosion when the land is cleared or is being grazed. Soil productivity is an additional consideration. Identify areas with deep, well-drained and highly productive soils to maximize yield of grasses. Exclude sites with environmentally sensitive features such as wetlands and the banks of streams.
Once your potential pasture site(s) have been identified, test your soils to determine the existing fertility and pH (acidity) of the soil. Fertile, slightly acidic soil is ideal for grass production. Test a soil sample for each site you are considering converting to pasture, making sure that the soil sample represents the entire area.
The Virginia Tech Soil Testing laboratory will test your soil for a small fee. Sample boxes, soil test forms and instructions are available in Fairfax County at your local library. Soil conditions must not be too wet or too dry when samples are collected. Collect soil samples with a sampling tube, auger, trowel or spade from the average root zone of grasses, 2 – 6 inches below the surface. At least five sub-samples or cores should per taken per acre and at least 20 sub-samples or cores should be combined to make up each soil sample. Cores or sub-samples should be thoroughly mixed in a plastic bucket before the sample box is filled with the soil.
Preparing the Site
Once you have determined the best location for your pasture, the actual physical activity starts with selective thinning (cutting down) of mature trees, and the removal of stumps. Trees and shrubs should be prioritized for removal in the following order:
- All trees and shrubs poisonous to horses, including red maple, chokeberry, common elderberry (American elder), golden chain tree, and buckeye.
- Trees that block sunlight from the pasture.
- Young trees instead of mature trees.
- Damaged trees over healthy trees.
- Trees on flat areas over those on steep slopes to minimize erosion potential.
Consider saving trees to provide shade for the horses, stabilize slopes, or to create a screen or buffer for the pasture. The trunks of saved trees should be protected using chicken-wire or wooden tree fences.
Install silt fences along the lower (downslope) limits of disturbed areas with the potential to erode and cause pollution in adjacent water bodies or off-site.
A cool-season perennial grass and legume (less than 25%) mix is recommended for horse pastures. Cool-season pasture grasses include orchard grass, Kentucky bluegrass and fescue. Consider the advantages and disadvantages of each grass species (see table) as you select the mix for your pasture.
Pasture seed mixes should contain legumes such as clovers or alfalfa. Legumes reduce bloating in horses and they convert atmospheric nitrogen to a form that is readily available for uptake by the grasses. In addition, legumes will increase the vegetation density of your pasture and crowd out unwanted weeds. As long as the amount of legumes in the seed mixture is kept at 25% or less, they will not cause excessive drooling among your horses.
For the seed mix, choose certified seeds to ensure a high rate of germination, good seedling vigor, and a lower percentage of weed seeds in the batch.
Preparing the Soil and Planting
Cool season grasses can be seeded either in early spring or late summer. The key is to ensure that the new plants develop mature roots before extreme winter conditions or adverse summer heat sets in. Late summer seeding is preferable because it takes advantage of the grasses’ normal fall root production period.
Before you plant, you will need to correct the nutrient and pH levels of the soil and prepare the seedbed. Plant nutrients are essential for seedling development and growth. The primary nutrient needed at the early stage is phosphorous which stimulates root and shoot growth. To add nutrients, broadcast fertilizer following the concentration and nutrient ratio recommendations in your soil test results.
Establishing and maintaining the appropriate soil pH (acidity) is essential for plant nutrient availability. The required pH level for optimal uptake of plant nutrients varies depending on the type of crop. The ideal pH for cool season pasture grasses ranges from 6.0 – 6.2. However, wooded areas usually have lower pH levels (more acidic soils) and require the addition of large amounts of lime to correct the soil pH. Acid soils (low pH conditions) can also be an indication of the presence of toxic levels of aluminum, iron or manganese in the soil. Liming reduces the toxic effects of these elements and improves the availability of essential nutrients such as phosphorous.
Agricultural limes don’t readily combine chemically with the soil so it takes a large amount (tons/acre) to significantly change the pH. To apply the lime most effectively, plow the amount recommended to a depth of 4 – 6 inches.
Once you have corrected the soil acidity and nutrient levels, you are ready to prepare the area for seeding. The pasture seedbed should be firm to allow uniform, shallow placement of seeds with an even coverage and to provide good seed-soil contact. Seeds should be planted no more than ¼ of an inch deep. The seeding rate depends on the type of seed mix you choose to grow. Your local Soil and Water Conservation District can help with rate recommendations.
Planting into a conventionally tilled seed bed usually proves to be more effective than no-till seeding. Both of these methods work better for grass species than frost seeding, which involves broadcasting seeds toward the end of winter while the soil is still frozen. Frost seeding relies on winter’s freezing and thawing cycles to work the seeds into the soil and is more successful with legumes.
If you are planting a relatively small area, spread hay or straw mulch to provide a more conducive environment for grass seeds to germinate and young plants to thrive. Mulching also reduces top soil and seed wash-off in case of a storm event.
Releasing horses too soon onto a newly established pasture for full-time grazing is a common reason for pasture failure. New grass must be allowed to develop deep, mature root systems before being exposed to the stresses of full-time horse grazing and trampling. Although brief periods of “flash” grazing can be supported by a new pasture, for the first year following establishment it is best to harvest the grass as hay while the soil settles and achieves adequate compaction. If the horses can’t be kept off the new pasture for the first year, consider dividing the pasture into two separate areas. One section is sacrificed and opened to grazing, while the other section is left to establish.
Regular soil testing, every three years, will provide you with current information on your pasture’s nutrient and lime requirements. In between soil tests, maintain adequate nutrient levels by fertilizing your pasture once every year, preferably fertilizing cool season grasses in the fall when root growth is strongest. Lime is typically re-applied once every three years to maintain adequate soil acidity.