Legume Root Inoculant

Asked January 18, 2020, 8:39 AM EST

I have used root inoculant on peas and bean seeds for many years. When I lived in California and planted in sandy soil the result would be large numbers of nodules on the roots. Since I started gardening in Maryland 10 years ago I see no nodules on either pea or bean roots when I pull them at the end of the season. I have bought inoculant from several different sources over the years. My soil here is loamy with a high organic component (soil tests show around 10% organic matter). So is the inoculant ineffective in my soil and am I wasting money on it?

Harford County Maryland

1 Response

Here are some thoughts. Your soil is high in organic matter. When you have a lot of available nitrogen there is not as much growth of the bacteria. An overabundance of nitrogen from fertilizer, manure or compost can reduce nodulation on the plants.
You can also check to make sure you have the right inoculant. Match the inoculant to the species.
Do not use chlorinated water when mixing the inoculant as this can kill bacteria. Try using distilled water. Unless the product was stored at high temperatures or kept wet, the inoculant should be okay.