By Bruce Anderson
Slow-growing alfalfa seedlings often can be an indication of low pH soil.
If you're planning to establish alfalfa next spring, take time this fall to test the soil pH and add lime if indicated.
Alfalfa grows best in soils with a neutral pH of about 7. When soils are acid, with a pH of 6.2 or lower, alfalfa plants do not grow as well. At a low pH, alfalfa roots are less able to absorb nutrients from soil. Also, the nodules on alfalfa roots that convert nitrogen from the air into nitrogen the plants can use will have difficulty forming and working effectively in acid soils.
Most sandy, low organic matter soils as well as heavier ground that has been tilled and fertilized with nitrogen for many years have become acidic and need a lime application.
It takes time for lime to really neutralize much acidity so I recommend applying lime at least four months before planting alfalfa. And while there is a cost, applying lime now is much less costly then having a stand failure or several years of low alfalfa yields.
Source:unl.edu