I'm sure it serves its purpose, but I have never used any. I get good results just planting them. I don't use any type of fertilizer on them either. I find they don't need anything. Your mileage may vary.

This question comes up fairly often; there is a good thread in the link below. I performed an experiment this summer to test the effectiveness of inoculants on various legumes (pulses), and am compiling the results soon... but several factors (herbivors, disease, some mixing of seed) may lead to less than conclusive results.

My personal belief is that for most locations where agriculture or gardening was done previously, beans do not need inoculant. This is not to say, however, that they might not perform better with- than without.

Here in the U.S., the bacteria are already present in much of the soil. In Australia, where beans are not native, this may not be the case... and potting soil, regardless of country, probably has little to none.

As Rodger stated in the thread below, the root nodules (which the inoculant bacteria create) just supply the plants with nitrogen. If nitrogen is already available from other sources (soil, fertilizer, organic matter, foliar feeding) then nodulation is not necessary.

For poor soils, an initial treatment with inoculant may be necessary. If you uproot a mature living plant (carefully) and find no nodules, then I would recommend an inoculant the following year.

Here is a link that might be useful: Granulated inoculant

Hi- thanks for all the info!
Zeedman, I have been following the inoculant threads & experiments quite closely, it's all really fascinating stuff. Very keen to hear the results of your experiments. The problem is that I'm still such a novice gardener that eventually that quantity of information just sort of tumbles out my ears- I don't have the experience yet to hang it onto my own knowledge about my own local conditions.
So, I figured I'd just start by planting some seeds, and when the time comes I know where to look for more detailed information.
Seeds planted a week ago, seedlings starting to poke up this morning, very excited to watch my first bean plants grow. I really hope they grow into the 'green curtain' I have envisioned for my porch window, but I guess the plants will let me know if it's possible or not.

I don't use inoculant but then, I have been growing beans in this garden for a long time.
Green Harvest include various inoculants with their green manure seeds, so I would suggest sending them an email. They will probably be able to answer your question about inoculants for beans.

Here is a link that might be useful: inoculants

I have tried both ways and have never seen any appreciable difference. If you have it, use it, it can't hurt. If you don't, plant them anyway and see what YOU think. I haven't used it in years and have excellent crops.

Glad I checked back- thanks for the link Solanum! My beans came from Green Harvest but I didn't find an inoculant link on their bean seeds page and didn't think to look on the green manure page.

It seems a bit funny that they'd include inoculant as standard with green manures but not with the edible legumes- I wonder why that is? I'll send them an email as you suggested and find out.

Oh well, my beans seem to be growing fairly well of their own accord. If I do another sowing for autumn I think I'll look a bit harder for inoculant, especially now that I've built garden beds- it would be a good thing to introduce into the garden ecosystem I think.

Did you ever get a straight answer as to where to purchase, a pre-made bean inoculant for those of us who are new to gardening, have failed with beans, do not have a compost bin(yet) and are a bit confused the bacteria aspect of an inoculant.

I have looked and asked at sereral garden centers.

Inoculant will help provide Nitrogen in early stage of germination to the growth level at which plant will set nodules to manufacture it's own N supply. plants do not have nodules at germination stage.This way ,in general,inoculated plants will grow vigorously right from begining.
However it may be assumed that there will be some N in the soil from the leaves and animals that will be enough for the plant to survive.
Inoculation will be a great help to farmers who are growing legumes on very large acreage where at the end ofthe season legumes will enrich the farms that will provide enough N to the next crop in rotation like corn etc. that will need N right from begining for healthy growth and save some money.