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**GilaMinumBeer** · 03-07-2008, 03:22 AM

Nitrogen fixing "green manure" plants to be specific.

I did a search for nitrogen fixing and came up only with links to nitrogenating beers so, please forgove me if this subjaect has already been debated or discussed.

I have recently been looking into benificial companion plants to take full advantage of my plot for hops. Turns out there are plants such as Alfalfa, Red Clover, Bluebonnets, etc.. that are organic means of providing free nitrogen to the soil.

These plants have a bacteria that converts the nitrogen in the air we breathe into notrogen compounds and binds them into the soil. Free nitrogen from an edible plant.

The technique is termed "Green Manure" and the plants are intended to be turned into the soil.

Hope this helps someone else out there. I intend to further explore the use of a blend of red clover and alfalfa seed for this very purpose.

david_42 · 03-07-2008, 01:48 PM

Hops are heavy feeders; nutrients and water. Any top cover would be competing for both. Based on the simple fact that none of the commercial hop growers do this, I'd say the disadvantages out weight the advantages. This despite western Oregon being one of the major grass/clover seed growing areas in the US.

Mycorrhiza use energy & nutrients to fix nitrogen, as well. One of my sisters did her PhD on adapting them to corn, but determined you lost far more than you gained.

Don't forget to setup a control plot. Otherwise, you'll never know if it actually made any difference.

**GilaMinumBeer** · 03-07-2008, 02:00 PM

I too was of the same frame of mind. What spawned the interest was reading the suggestion of using Green Manure in the Crannogales Hop Manual.

**pjj2ba** · 03-07-2008, 06:59 PM

All legumes will enter into symbiotic relationships with nitrogen fixing bacteria under the proper conditions. They are picky though, each species of plant has their own species of bacteria. I suspect if it were used with hops as a green manure, it would have to be only in the space between the rows, as it really does need to be turned under for full benefit. It would be very hard to do this right around the plants. One could just mow it to the ground (killing it) and that would help, but not a much as turning it in.

Maybe you could plant some early peas. They'd be dead by mid-to the end of June just when the hops really start to take off. Plus you'd get the bonus peas. Heck it is probably close to pea planting season down there. Peas don't like heat.

Also you then MUST NOT apply any nitrogen fertilizer!!! If you are getting it for free, why spend all of the energy to make little houses (nodules) for the bacteria to live in. A plant knows a good thing when it's got it. Seriously, if there is plenty of nitrogen already present in the soil, the plant won't bother with nitrogen fixation. This is why the corn to soybean crop rotation is so good. Corn rapidly depletes the soil of nitrogen and then growing soybeans the next year adds it back.

**GilaMinumBeer** · 03-07-2008, 08:20 PM

You make an excellent point about the location of these plantings. Yes, if intended to be utilized as a green manure then they must be turned in. And for the they must be planted in the in-bteween areas of the hop yard.

Secondly, yes again, there is no point in adding nitrogen fertilizers.

My intent is to use a annual to biannual addition of wood ash. From everything I have read to date wood ash provides all the necessary nutrients except Nitrogen and Boron. The legumes will provide the nitrogen and if needed I can apply a 1/2 teaspoon of borax per 100 SF to provide the Boron.

Ideally I would amend my soils in the fall with the Boron and Wood Ash to allow them to blend. And then of course the legumes will "grow" the nitrogen.

CBBaron · 03-10-2008, 01:54 PM

If you are tilling in the legumes then you are destroying any roots the hops have that can make use of the nitrogen. The benefit to the hops is going to be small and you will probably still need to provide nitrogen to the hops root ball.

Green manure works much better for annuals like corn or to establish so nitrogen in the soil for a new planting. An established hops field will see little benefit except as a mowable ground cover between rows of hops.

Craig

cek · 03-08-2009, 01:16 AM

It sounds like you are looking for something that can be used both as a nitrogen-fixer and a mulch. You don't have to mulch to get the benefits of nitrogen-fixation. If you just want nitrogen-fixation, you can interplant the plant with the hops and leave it there. Usually they are tilled into the soil in commercial farming, but that's because they are usually used as cover crops in a fallow field. They have to be tilled in to make room for the next crop. For home use, where you don't have to have rows for machinery, you can leave them in.

If you pick something deciduous (or annual), you can use the dead organic matter like mulch for water retention, though it takes a few years of dropped leaves decomposing before you get the same effect as a mowable ground cover that gets tilled in. If you pick a perennial, you can get weed suppression too. Legumes should work. Scarlet Runner Beans have beautiful flowers and can keep growing up to 20 years in the right climate. They'll definitely re-seed. Plus they give you beans and hummingbirds love them. The only drawback is they can be hard to keep in check. Also, they form large, woody, tuberous roots. Look into how that would interact with a hops rootball. Good luck!

**GilaMinumBeer** · 03-08-2009, 01:22 AM

I am going to use Dutch Clover.

As far as turning them in, I will do that when it's time to root prune. Therefore, the root system will not be compromised by the shredding nature of the cultivator. The Dutch clover is perennial so, I should only have to sow it once.

I figure with enough seed I can get atleast 3 of the beifits. Nitro-fixation, water retention (via ground cover), and weed control (via ground cover). That will be good enough for me.

k1v1116 · 03-08-2009, 01:28 AM

beyond the nitrogen fixing plants there are other benefits companion plants offer, marigolds grown near tomatoes help to fend of certain pests. I don't know of any plants specifically for hops but I bet that are things that help keep aphids and other pests away.

WhatsOnTap · 03-19-2009, 02:46 PM

I was at a sustainable hop conference in December, and they found great results with white clover as a companion. FWIW