Nitrogen fixing ground cover?

Hello everyone,

I was just wondering if anyone uses companion planting of fruit bushes/plants with nitrogen fixing ground covers such as clover and if so, did you notice a difference in growth?



i have acc wendy strawberries growing around my red gem goumi with no fertilizer and they are nice and green.

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Not to highjack the thread but is nitrogen fixing ground cover even relevant to the small orchard or garden?

On an industrial scale I can appreciate the magic of using nitrogen fixing ground cover, specially over the off time where lack of ground cover would lead to erosion and leaching of nutrients. Over hundreds of acres it saves in the equipment and manpower to improve and protect the soil. For small orchards? We are talking a flick of the wrist of fertilizer or some extra compost here and there.


I was going to use clover, but it produces flowers when I would need to spray the fruit trees with insecticide, which would then endanger nearby bees. So I’m just going to use grass and fertilize artificially.


most fruit trees need spraying up to early summer then after fruiting. most stuff im growing as a fruiting groundcover are fruiting after my last early summer spray and are done flowering by time i do my late summer sprays. just keep in mind when the stuff you put around them flowers and when you may have to spray your tree. in premaculture guilds they plant every third tree in the row a seaberry, goumi ,autumn olive or siberian pea shrub. can also use locust . they become large trees but you can coppice them for firewood ,fenceposts and tool handles. b. locust have one of the hardest, hottest burning, rot resistant wood in n. america and grows extremely fast.


a nitrogen fixing ground cover is definitely relevant to the small orchard or garden or even lawn. unlike phosphorus and potassium that bond to soils due to their negative charge, nitrogen easily and readily washes away in heavy rains. growing nitrogen fixing plants in a chop and drop scenario prior to flowering will ensure consistent nitrogen levels for ideal growth without spending money on fertilizers or risking runoff into local waterways. hence why my state (Maryland) has homeowner nitrogen fertilization laws while pushing for mulching. Lawn Fertilizer Schedule (Chart) | University of Maryland Extension


That’s actually my point. Your average backyard orchard is not a thousand acres of monocrops build specifically to drain excess water, with drainage ditches that outflow into bodies of water. Said orchard also does not spread fertilizer by the metric ton and more likely are just bashfully sprinkling a bit here and a bit there. Most backyard orchards are already doing the composting and mulching stuff.

Not to mention that a lot of the nitrogen fixing of cover crops comes from tilling the biomass under; while those plants are just doing their thing they are largely a consumer of nitrogen. I’m not replacing my highly effective mulch for a very ineffective nitrogen fixation that doesn’t even work that well under my orchard conditions.


Home gardens and lawns actually are much more significant sources of N pollution than farms. At the scale of a mega farm, you’re going to notice too much fertilizer in your reduced profits. At home, it’s a negligible expense compared to the effort of actually measuring how much you need.

Back to the main point of the post, any way you can find to tighten up your loops as far as obtaining fertility on site is at least worth considering. Nothing’s without drawbacks, and companion planting may make it harder to keep voles away or manage insect pests. But they can definitely provide a significant amount of N.


Not even close. From the USGS:


Once again; running a ground cover on an orchard will deposit negligible amounts of nitrogen unless you run a tiler to once a year to tile under your nitrogen-fixing crop. all while loosing the benefits of doing a tick layer of mulch.


Just as farm equipment (including on road vehicles) is not held to the same standards for pollution as most others where I live, Ag as far as I understand based on the last time I looked at the laws is not considered a point source pollution discharge the same way as a power plant or other industrial process, although they may actually be larger contributors to water pollution. In Pennsylvania, we’ve done a good job of cleaning up the abandoned coal mine drainage that the last few times I’ve looked, sedimentation is now our primary water quality issue (part of which comes in no small part from Ag industry).

I think as this is apparently a contentious topic (similar to some people’s choice to spray or not to spray), it would be great to keep it on topic and leave side discussion to a different thread if desired.

That being said, I think that nitrogen fixing plants on a small scale from a permaculture perspective is a great idea for the home orchard and I too consider nitrogen fixing around my budding orchard. I actually planted some sugar snap peas around a few of my pawpaws today to help out. I intentionally placed pawpaws near our redbud as it also is in the pea family and is a nitrogen fixer. I’ve planted lupine around some trees too but will be considering spray schedules with bloom timing as others had mentioned. With the pea family idea, they are cheap for a big bag and can be planted throughout the year, whether you actually plan to harvest them or not as a crop. That may be a good route for avoiding bloom issues, just wait until the season permits.


Ok, I stand corrected on the pollution. However, I stand by my assertion that nitrogen fixation by cover crop is a worthwhile pursuit.


@don1357 , have you grown Nfixers? If so, which ones?
I see you make a lot of “blanket statements”.
I’m curios on what experience or information those are based?

Soil bacteria, fixate N below ground
From my understanding and experience, this is incorrect.
Most N fixation happens in symbiosis with a soil bacteria. And the N deposits in little balls on the roots. You don’t need to till those, their already buried underground.

Annual N fixation vs perennial situation.
There are different ways to use N fixating crops though. Some fast growing annuals can be used as a follow crop. And are worked under just before sowing the main crop. After tilling you do get a N spike. But that’s not from burying the top part of the plant(the top part does not contain more N than other plants)
The N spike is coming from the killing of the plant, and thus more measurable N is released from the dying root nodules. The main factor in that measured N spike though is from soil mineralization. Breaking down soil organic matter due to tillage and as a side-effect releasing N stored in that organic matter.

Perennial N fixers and N availability
For an orchard instead of using annual N fixers, i think the perennial ones are more suited. A lot of research went into those for example to put in grass mixes. And they do seem to have large effects. (both measurable and empirically) The effects are sometimes hard to measure with “regular” test kits. Since most of the N that’s fixed by plants is not immediately water soluble. But it is however plant available from symbiosis between fungus and bacteria.

I do have to say though, putting 1 or 2 single N fixing plants next to a tree, probably won’t replace your regular fertilizations.

Wood chips and organic matter
And wood chip mulch is also excellent for the soil. Hauling over woodchips is a lot of work. And not everyone has enough wood chips.
Wood chips also have an environmental cost. They are moved from 1 spot to another. Which over time can slowly lessen the soil qualities of where they are “harvested”

If i had easy access to wood chips, id likely use those. If not just for the convenience of them. However i think a perennial ground cover (n fixing or not) also have a lot of advantages for the soil. Generally the N fixing ground covers don’t build a lot of extra organic matter in the soil. The non N fixers do that more. But usually you will slowly increase organic matter in an orchard anyway, since your moving away from tilling.


some clovers are bred to be mow able. If your sowing gras you also have to mow it.

You could just mow the clover before spraying. And the bee’s are safe. (mow a few days ahead so there are no more alive flowers)


I’m a commercial grower but wasn’t always so i want to tell you everything we all do matters. Its my opinion legumes make a huge difference. There is no chemical i want to use unless i have no choice.


I’m just an avid aficionado like anybody else here so what I say should be taken with as much skepticism as anything else you read on the internet.

Having said that think about those nitrogen nodules, which the plant uses as reserves; when does that nitrogen gets released into the soil? As long as that plant is alive it will either consume nitrogen or stash it away; it is not until the plan dies (an event that happens on schedule when tiled over) that the nitrogen is finally released into the soil.

The amount and kinds of efforts we put into our backyard gardens is a whole different ballgame than the amount and kinds of efforts that goes into commercial applications. Recently I bought a 2 1/2-foot tall carmine jewel shoot for $20 bucks. It was basically a 14" round of grass turf with the expected mangle of grass roots. I took it home and in a tote full of water I kept soaking and taking it apart until I managed to take it out of that mess and potted it. I also managed to extract two parallel roots, potted three chunks, and one is taking already. From a backyard perspective that was a brilliant move but if I was in the business of selling plants, that would have been a waste of time due to how inefficient it would have been. Or the fact that I have no need to spray pesticides because It is my pleasure to walk an inspect my orchard between 2 and 8 times a day, and I pick bugs by hand. Again, works great, not feasible on a commercial scale.

I just don’t see much value on nitrogen fixers at the scale we backyard orchards face. That is, unless you tile over the crop to release the nitrogen that is fixed there.

I plant Fava beans and Wheat in September for a Winter Cover crop

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@clarkinks I recently acquired a few acres of sloped farm land and I want to plant several dozen paw paw trees. The farmer has the right to finish farming this season, so I’ll probably plant the trees next spring. It is 50 minutes from my home. I can mow in between rows occasionally, but I’d like to limit my trips. What do you recommend for ground cover between orchard rows that won’t grow too high or too fast?

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i plant N fixers not just for the fertilizer but for other uses. i like autumn olive/ goumi for the fruit ,siberian pea shrub for the 40% protein seeds i give to my chickens and the huge amount of yellow flowers for the bees. i can grow them in my gravelly part of the yard with no amendments and they will improve that soil over time. while they arent a complete substitute for good fertilizer, they give back in other ways. when im eventually able to purchase some land, i intend to plant part of it with black locust and red oak. both are fast growers, valuable as timber/ firewood and give back to wildlife. animals eat the seeds and acorns. bees love the abundant black locust flowers and black locust is a N fixer which over time improve the soil. b. locust is also coppices well and the wood is great for tool handles and fence posts as it very rot resistant. so you cut a mature b. locust for timber firewood, in a few years you have a abundant amount of saplings coming from the roots = dozens of axe handles or let grow for a few more years you got 50+ fence post you can sell that last longer in ground than cedar. it only makes sense to grow N fixers. my 2 cents.


@Steve, this is the sort of ground cover use that (to me, humbly, Mr. internet random dude) makes sense, one that has other practicalities. As my trees get bigger I want to try small bush beans, strawberries, and low bush cranberries. Traditional Japanese orchard ladders were specifically build by the growers with tall legs so they could be positioned around a under canopy garden. The distance to the first rug was to your knee, the wide rug was so the top of the ladder would hit your hip bone, for good stability when standing off center on it.


About black locust; keep in mind that the strongest north American wood is not commercially viable because the locust boring beetle will eventually find your trees and put holes on the wood. This won’t hurt the tree much, but it makes the wood suitable for harvesting outside of fence posts and the like. It is an amazing source of bee nectar; I had a few black locust trees when I lived in Maryland and the honey could go from super clear to slightly yellow. If you have a choice go for black walnut, hickory, and chestnut; veneer quality logs can fetch a pretty penny, plus (eventually) you get the nuts. If you want to do the whole permaculture forest thing you can do those taller trees for the upper canopy, filbert nut trees for the middle, and (if a southern exposure with morning light) shade tolerant ground level bushes.


I’m not sure how what I wrote supports your point. runoff is a problem everywhere, regardless of drainage ditches meant to outflow into local bodies of water, hence the link I shared regarding residential limits on nitrogen fertilizer, not commercial limits measured in pounds not metric tons. additionally, proper use of nitrogen fixation as a cover crop does not require tilling the biomass under, you simply chop it and drop it in place to decompose as a green mulch prior to fruiting so the nitrogen stored in the roots and shoots aren’t expended into the fruit decreasing the mass of the plant. the plants both use and store the nitrogen so utilizing them in this fashion maximizes the available nitrogen for surrounding plants.

No one is telling you that you have to use a groundcover in place of other practices to amend your soil with nitrogen. I myself amend with organic fertilizer containing nitrogen and succession plant to maximize nitrogen in my veggie garden (classic peas followed by cucumbers). If you want to keep doing your thing, go for it. no one is saying otherwise. maybe it is ineffective for you, but the practice is proven affective as a whole.