[abcanthur]

I have a small raised bed dedicated to my first Three Sisters growing right now. Just planted beans a few days ago now that corn has had a head start. Rookie gardener, but hoping for at least some visual interest if not production. The beans are supposed to fix nitrogen which helps the other plants, but does anyone know if this requires a year to pass where the old bean plant decomposes into the soil? Or is merely bean plant presence enough to share nitrogen?

[frogulis]

My understanding is that the nitrogen-fixing is actually done by bacteria that they have a symbiotic relationship with. How cool!

[kaitai]

It's bacteria that live in the bean roots that do it continuously. Read more about rhizobia here: https://www.gardenbetty.com/a-look-at-legumes-rhizobia-and-r...

[kaitai]

For those who don't want to read the article, it's important to note that if rhizobia are not present in your soil, you may want to inoculate your soil with it to get things going. It doesn't come along for free with a bean or pea seed, although some rhizobia are present in most soil.

[hosh]

I think they have to die and turned into compost, so the benefit is for the next season.

It’s similar for notill techniques — it can take five seasons before it hits a threshold and the soil becomes more productive than with conventional methods.

[fuzztester]

Interesting point, never thought of it before, although I knew about nitrogen fixation. Google the term, Wikipedia may have the answer. I will too.