Planting clover (a Trifolium species) in Oregon requires careful timing due to the legume’s need for specific soil moisture and temperature conditions for successful germination. Whether used as a ground cover, a lawn alternative, or a functional cover crop, clover’s establishment period is delicate. The goal is to provide the seeds with sufficient water and moderate temperatures, allowing them to anchor their root systems before facing the stress of summer heat or winter frost. The success of a clover planting project is determined by aligning the seeding schedule with Oregon’s diverse regional weather patterns.
Benefits of Planting Clover in Oregon
Clover offers numerous advantages for Oregon gardeners and land managers, starting with improved soil fertility. As a legume, clover fixes atmospheric nitrogen into the soil through a symbiotic relationship with Rhizobia bacteria. This process can supply 50 to 150 pounds of nitrogen per acre, reducing the need for synthetic fertilizers and preventing nutrient runoff.
The extensive root systems of varieties like red clover break up compacted soil and increase organic matter. This improves soil structure, enhancing water infiltration and reducing surface erosion during wet winter months. Clover is also drought-tolerant once established, maintaining a green color through drier Oregon summers. Additionally, the plant’s flowers attract beneficial insects, supporting local pollinator populations.
Timing Your Clover Planting by Oregon Region
The state’s geography creates two distinct planting schedules separated by the Cascade Mountains, making a single statewide recommendation impractical. Western Oregon, including the Willamette Valley and Coastal regions, experiences mild, wet winters and dry summers, offering two primary windows for successful seeding.
Western Oregon
Early spring planting, typically from March through mid-April, allows the clover to establish itself during increasing temperatures and reliable moisture. Late summer or early fall planting, generally from mid-August through September, is often preferred. This autumn window provides seedlings with cooler temperatures and consistent natural rainfall, minimizing the need for supplemental irrigation. Fall planting gives the clover a head start over aggressive spring weeds, allowing it to develop a strong root system before winter dormancy. For cover crops like crimson clover, seeding before October 1 is recommended to ensure establishment before the first hard frost.
Eastern Oregon
Eastern Oregon, encompassing the High Desert and mountainous areas, has a shorter growing season with harsher, colder winters and a greater risk of late-spring frost. Planting should be delayed until late April or May, after the soil temperature has consistently warmed and the threat of a hard freeze has passed. This timing maximizes growth during the brief summer while avoiding freezing temperatures that cause winter-kill or frost heaving. Early fall planting is possible, but requires ensuring the clover has at least six weeks of growth before the first expected freezing conditions arrive.
Essential Steps for Successful Clover Seeding
Proper site preparation is required for successful clover establishment, regardless of the season. Existing weeds and turf must be removed or suppressed before planting, as broadleaf herbicides will destroy clover seedlings. The soil surface should be lightly raked to create a fine seedbed and ensure adequate seed-to-soil contact.
Clover seeds are small, and a broadcast spreader works well for uniform application, typically at a rate of 15 to 25 pounds per acre for varieties like red or crimson clover. Gardeners often mix the seed with an inert carrier, such as sand or fine sawdust, for even distribution. After broadcasting, gently rake the seed in or lightly press it with a roller to ensure it is not buried deeper than a quarter-inch.
The most important step following seeding is providing consistent moisture during the germination period. The seeded area must be kept continuously moist for the first two to three weeks until the seedlings emerge and anchor their roots. Light, frequent watering is necessary, especially during warm or dry periods, to prevent the delicate seeds from drying out before they fully establish.