The How and When of Pasture Renovation

Western Washington and more specifically, Snohomish County, has an ideal climate for growing grass. One of the reasons for this is due to our temperate climate with plenty of rainfall. For example, the city of Snohomish averages 50 degrees Fahrenheit and has about 275 frost-free days per year. This is accompanied with about 35 inches of annual precipitation.

Grass species well-suited to our area are typically perennial ryegrass, tall fescue and orchard grass. However, there are many more grass species that may be better suited to your soils and intended use. If your pasture or hayfield is not performing as you would like, or is mostly taken over by weeds, it may be time to think about giving your pasture a new lease on life.

Renewing an old pasture is easier and less expensive than establishing a new one. Often, pasture grass health and yield can be improved by increased management including controlling weeds, adhering to recommendations from a soil test and managing your livestock’s use and time out on the pasture.

First - Evaluate What’s Growing There Now

One of the first steps is to evaluate the current management of the site. What is growing there now is what is best adapted to how the site is currently being managed. If the area is reseeded, but the management does not change, the site will soon return to its present condition. Management changes might include adding cross fencing to allow more intensive grazing and creating a winter confinement area. Grazing when grass plants are dormant and soils are saturated in the wet winter months leads to compaction, weed infestations, increased mud and runoff to surface water (creeks and streams) and poor, damaged grass stands.

Next – Decide When to Reseed

One can reseed a pasture anytime in spring or early summer but it’s recommended to approach this task in the fall. This is mainly because, in the fall, grass plants will have more time to become established, allowing for earlier grazing in spring or summer (depending on your site conditions and how quickly your grass establishes). Taking a soil test to determine nutrient and lime requirements is key to the success of your new seeding.

If lime is needed, fall is a good time to apply lime based on results of your soil test. This extra time allows for the lime to react chemically with soil particles and buffer the pH in time for spring growth. Planting in spring is possible as long as the soil is not too wet to be worked. As most people are aware, weather patterns in Western Washington frequently include a fair share of precipitation, which can prevent field work. A late spring or early summer planting is possible if irrigation is available in case conditions are dry.

Selecting the Best Forage Species

Forage species selection is important for the long-term success of the planting. If species are selected that are not best-suited for the site or intended use, the seeding will fail over time and the process will need to be restarted. Things to consider are: type of livestock using the pasture, climate, your soil type, availability of nutrients and level of pasture management.

Pastures that receive a high level of management can use a species such as perennial ryegrass, as it may be more challenging to grow. Pastures receiving less intensive management would be better suited to tall fescue, in either wet or dry conditions. Orchard grass is well adapted to our coastal environment as well as shady areas, and is an excellent choice for both horse and cattle pastures. 

If you are wondering whether to seed only one or multiple species at a time, multi-species mixtures can be managed successfully under intensive grazing systems. For less intensive grazing systems or for hay production, a simple mixture with only a single grass and a single legume species may be best suited to your site.

The drawback to multi-species mixes is they differ in palatability, seasonality, yield potential and response to growing conditions. This can result in patchy conditions due to selective grazing by livestock.

And Then There’s Weeds!

Controlling weeds or unwanted grass species at planting time and afterwards is critical to the success of your new seeding. Mechanical methods such as mowing or clipping are effective and are sometimes referred to as one of the best methods of weed control. Annual weeds generally grow faster than seedling grasses and legumes so they become taller, shading out your desirable species. Clipping above the growing forage grass and removing the weed’s growing points can stunt or even kill undesirable plant species. As the forage grass becomes more established, it will soon out-compete the weed population.

Although it is often more expensive, another option is the use of selective herbicides. In a new planting without the presence of legumes, a broadleaf herbicide can be used to control broadleaf plants/weeds. A wide range of herbicides are available for use. For current control recommendations or more information, consult the current edition of the Pacific Northwest Weed Control Handbook or call a licensed consultant.

Starting Fresh

If you have decided to completely renovate your pastures and start fresh, something to keep in mind is to only renovate about 25 percent of your fields in one year. This is because livestock will still need pasture to graze or you may be planning to make hay for future use. Also, a new seeding is not always guaranteed to emerge as planned. A newly seeded pasture may take nine months to a year to become established enough to tolerate grazing. Winter flooding or dry conditions can also damage or kill a new seeding before it is established.

If your newly seeded pasture is growing well and it looks like it would be an appropriate time to turn your animals out, use the ‘Pull-Test’ to help determine plant readiness. This is done by grabbing a single forage plant and giving it a sharp tug. If you can pull out the plant, so can your livestock. Don’t turn your animals out until your grass passes the pull-test. Even then, allow only light grazing until your pastures are well established.

To Summarize - Renovate vs. Starting Over

Methods to try before completely starting over:

  • Control undesirable plants by clipping, intensive animal grazing, chemical control or rest from grazing
  • Based on your soil test, fertilize and lime to stimulate existing desirable plants and to adjust the pH
  • Over seed the existing pasture with desired grasses and legumes

For more information on forage species and adaptation by use and soil type, refer to WSU Extension bulletin - EM 8645 by F. Lundin (1996) and bulletin 1870 - Pasture and Hayland Renovation for Western Washington and Oregon by Fransen and Chaney (2002). For more information on reseeding pastures in our area or to receive a free site visit, contact Snohomish Conservation District resource planners at