A fellow garden blogger (Patrick at Bifurcated Carrots) recommended I try inoculant for my peas and beans this year. Last year I had a miserable crop of both and was ready to give up, on the peas at least. But, here I am, giving it one more try. This year with inoculant. Its the first time I’ve ever used this, so I did some research.

The inoculant I used is garden combination inoculant from Johnny’s Selected Seeds, called N-Dure. It contains a mix of rhizobium bacteria: rhizobium leguminosarum viccae, rhizobium leguminosarum phaseoli, and bradyrhizobium sp.

Bradyrhizobium sp. treats lima beans, rhizobium leguminosarum viccae treats fava beans and garden peas, and rhizobium leguminosarum phaseoli treat dry beans and string beans. I don’t think this mix includes the bacterium needed by soybeans (bradyrhizobium japonicum), but I will use it with my soybeans anyway in case it helps. Here’s a chart for what treats what.

What’s inoculant? Here’s some excerpts from an informative fact sheet: “The ability of legumes to ‘fix’ nitrogen depends on the presence of special soil bacteria, known
as rhizobia, which invade the roots of legumes to form nodules. Within the nodules the bacteria convert, or fix, nitrogen from air pockets within the soil into forms useful to the legume plant. When the legume plant decays, the fixed nitrogen becomes available to subsequent crops. The fixed nitrogen is released slowly, often over a period of several years.

Each legume species has a specific rhizobial requirement. For example, rhizobia that infect medics are different from those that infect clover, peas or lupins. If the correct strain of rhizobia for a particular legume is absent in the soil or in very low numbers, effective nodulation will not occur and little, if any, nitrogen will be fixed. In this case the correct strain of rhizobia must be supplied at sowing. This process is known as inoculation.

Inoculation is essential when a legume crop or pasture plant is new to the land on which it is being sown. Once an effectively nodulated legume crop or pasture has been grown, and the rhizobia have been established in the soil, there is no need for inoculation with rhizobia in future seasons”.

I’ve read that chlorinated water kills the inoculated rhizobia, so I’m hoping mine do OK. I had to water a few times last week using our chlorinated tap water. But generally, we’ve had good rainfall this spring. So far, my pea germination has been great!

Fabaceae
Pisum sativum

topic: soil