Sainfoin is a tall-growing, perennial legume with fragrant, conelike clustering flowers. It is a drought-resistant plant that adapts well to soils with high pH levels. Native to Asia and Europe, the sainfoin is a noncompetitive plant that is commonly used for hay and livestock feed. It has a relatively short blooming lifespan, between 5 and 20 years.
Soak sainfoin seeds in rhizobium solution, which can be found at local nurseries. Rhizobium helps to stabilize nitrogen levels, something required for successful development.
Immediately after soaking, plant the seeds ¼ to ½ inch deep in well-drained soil. Plant your sainfoin seeds or seedlings in the early spring. Proper timing is essential with sainfoin. The plant requires ample germination time and growth before entering into the summer's dry period. The soil should be well drained and contain high pH levels--greater than 7.0. Sainfoins are noncompetitive plants and should not be planted near grains, oats and fruit trees, as they will be quickly overcome by the loss of nutrients. Scatter your seeds in the selected area or plant in organized rows. Allow at least 6 feet between planting areas to prevent clustering.
Water your sainfoin regularly while avoiding overwatering. Moderate watering will allow the sainfoin to receive its required nutrients without causing wet feet. During summer months, you may need to water your sainfoin two to three times each week. Adjust your schedule for rainfall and excessive heating. Pull back on your watering schedule as temperatures begin to cool in the fall.
Control weed growth in and around the sainfoin. Since sainfoin is not a competitive feeder, weeds can quickly deprive sainfoin of its required nutrients. Sainfoin are vigorous growers, however, and proper cultivation will allow the sainfoin to quickly outgrow. Mow the sainfoin during its first established year to control the weeds without injuring the sainfoin. Use preemergent and postemergent weed treatments to eliminate the establishment of weeds.
Harvest your sainfoin in mid to late fall, when the plant exits its growing stage. If you are cultivating for hay or feed purposes, cut the sainfoin halfway through its blooming stage. Pasture sainfoin should be grazed between its early budding and early blooming stages.