Self pollinating perennial nitrogen fixer suggestions??

hello everyone this is my first post here

I really want to start a mostly hemp farm because of their seeds and the major nutrition from eating them.
the problem im having is finding some good Self pollinating perennial nitrogen fixers that would be a good companion plant with hemp.
any plant suggestions well known or obscure would be very much appreciated.

side notes,

im planning for the farm to be in zone 8
it doesn't have to be edible but i would prefer edible plants

In what way do you expect the nitrogen fixer to help the hemp?

Since hemp will most likely grow as a homogenous block and usually blocks out light to anything under it, I would say interplanting with for example some kind of shade-tolerant clover would likely not go so well.

And if you only plant you nitrogen fixer on the edges of the hemp field, there can't be much of a nitrogen effect.

2 things come to my imagination:

- Since zone 8 does have frost, hemp will not stay in your field all year so you can use a nitrogen-fixing winter cover crop - such as crimson clover. This will give a nitrogen boost to the crop that comes after it, ie. next year's hempl. You can either turn over the clover immediately when chance of frost is gone or wait for it to flower so bees can harvest it (if you / neighbors keep bees). Note that crimson needs to get sown about 2 months before first frost so it can get established well.

- Sticking more closely to your request, a perennial solution would be for example to make a border of N-fixing perennials that would also serve as a windbreak / improvised privacy fence if that's of benefit in your location. Nothing very tall because hemp preferes sun. So, for example, the elaeagnus family could work well and also provide edible berries.

How about prarie mimosas?

Crt Jakhel wrote:In what way do you expect the nitrogen fixer to help the hemp?

Since hemp will most likely grow as a homogenous block and usually blocks out light to anything under it, I would say interplanting with for example some kind of shade-tolerant clover would likely not go so well.

first thank you very much for your in depth response.
i had an idea about planting many small clusters of hemp with nitrogen fixers/pest repellent plants surrounding the clusters so the companion plants will have access to much more sun.
do you think something like that would work?

Not meaning to rain on your idea. But you asked.

I think you should start with the question: why nitrogen fixers for hemp?

In my experience hemp is able to grow just fine without surplus nitrogen... And if it gets a lot of it, it will just go crazy.

For production of flowers and seed, P and K are, I would say, more important than N.

My neighbors (well, a village away) grow hemp and also keep chickens. They got the idea of spreading chicken manure on their hemp field. A jungle happened - hemp plants 10 ft tall. I suggested they consult a local acrobatic airplane pilot, maybe he could do a low pass overflight (he likes to do those) and nicely slice off the tops. In the end they decided, in true perma fashion, to stack functions: since they also use their property as an event venue, they turned a wedding into a hemp harvesting festival so their paying guests did the work.

The previous suggestion of crimson clover was based not only on N which you explicitly wanted but also on the fact that it will generally improve the soil with its roots and with its decayed organic matter once you plow it under. That, and the benefit to bees in the spring which will work even if there is a late frost (tested and succeeded). You may also want to look into buckwheat as a P accumulator. The bad part is that unlike crimson, buckwheat will definitely not overwinter which means it would be competing for field space with hemp during the warm growing season.

I think your idea of making a kind-of-chessboard of hemp interspersed with other plants should work in principle. It would however make harvesting somewhat less practical. You need to weigh this against the possible upside that you expect from such a planting. Granted I don't have a whole lot of hemp experience. But from what I do have I'd say it's a fairly robust crop (especially once the phosphorus needs are covered), very able to hold its own.

Working in patches makes sense for that crop.

I'm also not 100% on the need for a strong nitrogen fixer to be present.

If that's what you're wanting to do though, you could consider sunn hemp (Crotalaria juncea), which should keep pace with the hemp, drop a good amount of nitrogen and has a host of other benefits beside. And with both those hemps there, you would have a huge fiber opportunity! I don't know if Sunn hemp and hemp play nice though, as Crotalaria has been known to get a little allelopathic in the wrong company.

Other options are, to my mind, mostly shrubs and trees: Eleagnus spp (russian olive, silverberry), Caragana spp(Siberian pea shrub, Dwarf pea shrub), Prosopis (honey mesquite, velvet bean mesquite), Black locust (Robinia pseudoacacia), Honey locust (Gleditsia triacanthos), maybe alders or acacias. What will grow best depends on more than just your zone, of course, but at least one of these would fit.  

Annual rotation cropping between those perennials does also sound like a good idea. You could even do a Fukuoka style approach and throw down whatever winter cover crop works best in your area a week or three before harvest, so that when you chop down the hemp your soil stays covered.