Orchard grass (Dactylis glomerata) is a highly valued cool-season perennial grass used widely across agriculture. This robust species is frequently utilized for creating productive pastures, high-quality hay, and effective erosion control. Its popularity stems from its high forage yield, excellent palatability for livestock, and its ability to thrive in well-drained soils. Determining the correct amount of seed to plant per acre is foundational for establishing a healthy stand. The specific seeding rate must be calculated based on whether the grass is planted alone, its intended agricultural use, and the chosen planting method.
Baseline Seeding Rates for Pure Stands
The starting point for determining planting quantity is the rate for a pure stand, meaning orchard grass planted without any other species. For a dense, monoculture stand, the general recommendation ranges from 8 to 12 pounds of seed per acre (lbs/acre) when using a mechanical drill. This rate ensures sufficient plants establish quickly to suppress weed competition and achieve maximum forage density.
Growers must account for the quality of the seed lot by calculating the Pure Live Seed (PLS) percentage. PLS represents the actual percentage of viable seed within the bulk bag. It is determined by multiplying the seed’s purity percentage by its germination percentage and dividing by 100. For example, a seed lot with 90% purity and 85% germination contains 76.5% PLS.
The standard bulk rate of 8 to 12 lbs/acre often corresponds to a target of approximately 4 pounds of PLS per acre for optimal establishment. Ignoring the PLS calculation can result in an under-seeded field, leading to a thin stand prone to weed invasion. Therefore, the final pounds of bulk seed needed per acre is the recommended PLS rate divided by the PLS percentage of the purchased seed.
Adjusting Rates for Mixtures and Intended Use
The baseline rate is significantly modified when orchard grass is planted in combination with other species, particularly legumes like alfalfa or red clover. Planting orchard grass in a mixture requires a reduced seeding rate. This prevents the competitive grass from dominating the slower-establishing legume companion. If the grass is seeded too heavily, it can quickly out-compete the legume, resulting in a grass-heavy stand that requires nitrogen fertilizer sooner.
When mixed with a legume, the typical orchard grass rate is reduced to a range of 2 to 8 lbs/acre, often falling on the lower end depending on the desired final composition. For example, a common high-quality hay mixture might involve planting 3 to 4 lbs of orchard grass alongside 18 to 20 lbs of alfalfa per acre. This ratio encourages a balanced stand where the alfalfa provides nitrogen fixation and the grass offers a fast-drying, high-fiber component.
The intended use of the stand also dictates the final density and rate. A field managed for frequent, high-quality hay harvests targets a higher plant density and requires a rate near the upper end of the recommended range. Conversely, a field intended for light, continuous grazing may tolerate a slightly lower rate, focusing on persistence rather than maximum yield. For critical area treatments or erosion control where maximum ground cover is the goal, the seeding rate may be doubled compared to a standard drilled rate to ensure rapid soil stabilization.
Successful Seeding Methods and Timing
The planting method directly influences the final quantity of seed required per acre due to varying efficiency levels. Drill seeding is the preferred method for establishing forage stands because it places the seed at a precise, uniform depth, leading to better seed-to-soil contact and a higher germination rate. Due to this efficiency, drilling requires the lowest amount of seed to achieve a successful stand.
Broadcast seeding, where seed is scattered across the soil surface, is less efficient, as many seeds fail to make sufficient contact or are left exposed. To compensate, the seeding rate must typically be increased by 25 to 50% compared to the rate used for drilling. Following broadcasting, passing a cultipacker or roller over the field is necessary to press the seed firmly into the soil surface for successful germination.
Regardless of the method, the seed must be planted shallowly, ideally between 1/4 and 1/2 inch deep, as tiny seeds have limited energy reserves. Planting timing is optimized during one of two periods: early spring or late summer. Late summer plantings, made six to eight weeks before the first hard frost, are often the most successful due to cooler weather and less weed pressure. Early spring plantings must be done as soon as the soil can be worked to allow seedlings to establish a deep root system before summer heat and drought.