What is it?
Inoculant is Rhizobium bacteria that is applied to legume seed (clovers, cowpeas, etc.) before planting. The nodules on the roots of legumes contain Rhizobium bacteria, which are responsible for fixing nitrogen for the plant. Applying inoculant to the seed ensures that the correct type of bacteria specific to that legume are available to the plant once it germinates.
Do I need it?
Rhizobium bacteria is found in many soils, but planting legumes that have not been inoculated is taking a chance as to whether or not the specific strain of bacteria required for that legume is already present in the soil. In many cases, once a successful crop of a specific legume is grown in a field, there will be sufficient quantities of Rhizobium remaining in the soil to accommodate another planting of the same legume. But, many factors, such as cultural practices, weather conditions and soil conditions, may affect the survivability of the carry-over Rhizobium in the soil. In short, many people grow successful stands of legumes from seed that was not inoculated. However, there is no guarantee that the proper type of Rhizobium for the legume you are planting is present in your soil. Inoculating the seed is good insurance that the plant will be properly equipped to grow to its maximum potential and compete.
How do I apply it?
Some seeds are sold already coated with inoculant. In the case of un-inoculated seed, the inoculant will need to be applied and mixed with the seed before planting. The first step is to purchase the appropriate inoculant specific to the type of legume you are planting. Be sure that you have enough inoculant to treat your seed. Inoculant generally comes in the form of a fine, black powder sealed in a plastic package that should state which type of legume it will treat and how many pounds the package will treat. Also, check the expiration date on the package to make sure that the inoculant is still viable. The next step occurs immediately before planting. Dump the seed into your seed drill, broadcast spreader, or whatever type of planter you are using. Then apply the appropriate amount of inoculant to the seed. Stir the mixture until you feel that the inoculant has come into contact with the majority of seed. Then plant the seed as normal.
Some people have used liquids like milk, water or even soda pop as an adhesive agent for getting the inoculant to stick to the seed. If you choose to do this, be careful not to apply too much. Also, some liquids may damage the Rhizobium with any acidic contents they contain.