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  • What Should I Do?
    Alfalfa: Phil Williams

    Growing Nitrogen Fixing Plants

    Great garden companions for fertility
    by Phil Williams

    Monday, March 9, 2015, 7:38 PM

For those of you into permaculture, you know the importance of nitrogen fixing plants. These plants, especially when pruned release nitrogen into the soil, helping to boost fertility to the plants nearby. By practicing chop and drop when moisture exceeds evaporation, you can supercharge the establishment of a food forest, or a timber forest. These plants can also be great companions in a garden or orchard. Be careful in the garden, as some nitrogen fixers can be invasive.

Alfalfa

Below is a list of nitrogen fixers to consider establishing in your garden or food forest. (I put a * next to the plants I am personally growing)

Common Name

Plant Type

Zone Hardiness

Comments

Black Locust*

Full Size Tree

 

Large thorns, some say is allelopathic.

Mimosa*

Small Tree

6

Edible leaves

Alder*

Small to Med Tree

 

Size depends on variety

False Indigo*

Shrub

5

I had bad luck establishing this plant

Siberian Pea Shrub

Shrub

 

 

Redbud*

Small Tree

5

Some debate whether or not it shares the nitrogen it fixes.

Silverberry

Shrub

2

Eleagnus family

Russian Olive*

Shrub

2

Said to be invasive, Eleagnus family

Goumi*

Shrub

6

Good tasting berries, Eleagnus family

Autumn Olive*

Small Tree

 

Eleagnus family

Kentucky Coffee Tree*

Med. Tree

4

I have lots of these trees.

Sea Buckthorn*

Shrub

 

 

Golden Chain Tree

Med. Tree

5

Poisonous flowers

Spanish Broom

Shrub

8

 

Afalfa*

Groundcover

5

Strong tap root

Groundnut

Groundcover

 

Edible seed and root

Lupine*

Groundcover

5

 

Sweet Vetch

Groundcover

 

 

Wisteria

Vine

6

Very fast growing

Acacia

Large Tree

7-10

 

Mesquite

Med. Tree

7

Can deal with dry climate

Clover*

Groundcover

 

Good for pathways

Young Food Forest with Swale

References:

Gaia's Garden: A Guide to Home-Scale Permaculture, 2nd Edition by Toby Hemenway

~ Phil Williams

Phil Williams is a permaculture consultant and designer and creator of the website foodproduction101.com.  His website provides useful, timely information for the experienced or beginning gardener, landscaper, or permaculturalist. Phil's personal goals are to build soil, restore and regenerate degraded landscapes, grow and raise an abundance of healthy food of great variety, design and install resilient permaculture gardens in the most efficient manner possible, and teach others along the way.

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7 Comments

  • Thu, Mar 12, 2015 - 11:49pm

    #1

    pinecarr

    Status Gold Member (Offline)

    Joined: Apr 13 2008

    Posts: 1085

    Good article Phil!

    Now if only that nasty residual foot or two of snow would take leave of my garden…

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  • Sat, Mar 14, 2015 - 2:20pm

    #2

    Phil Williams

    Status Bronze Member (Offline)

    Joined: Oct 14 2009

    Posts: 269

    Thanks

    Thanks Pinecarr, I appreciate it.

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  • Sat, Mar 14, 2015 - 7:11pm

    #3
    robie robinson

    robie robinson

    Status Gold Member (Offline)

    Joined: Aug 25 2009

    Posts: 868

    not mentioned but becoming indespensable is

    Sunn hemp, i flash graze about 100 ewes plus lambs 3-5times /summer. corn grows well without fert. every 3rd year

     

    its baahhd stuff

     

    http://www.petcherseeds.com/about-sunn-hemp/

     

    obtw, as a long time farmer, hairy vetch, austrian winter peas, white clover,alfalfa, sunn hemp, and $#!t/manure are about all i need. ruminants of course. now to get that mare bred so oil will be of even less value than…

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  • Tue, Mar 17, 2015 - 7:25pm

    #4
    Thetallestmanonearth

    Thetallestmanonearth

    Status Bronze Member (Offline)

    Joined: Feb 28 2013

    Posts: 308

    golden chain tree

    I have read that the seed pods of this are poisonous as well as the flowers.  They look a lot like honey locust which grazing animals go nuts for.  Probably best to avoid this one in a system where animals graze and make sure all family members know not to eat from it.  Beautiful tree though!  One of my wifes favorites!

    Enjoy your day.

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  • Tue, Mar 17, 2015 - 8:36pm

    #5
    Doug

    Doug

    Status Platinum Member (Offline)

    Joined: Oct 01 2008

    Posts: 1368

    forest gardens

    Thanks for the article Phil.  I have a fledgling (about 3yo) forest garden and have been thinking of planting nitrogen fixing shrubs near my fruit trees.  Would that provide sufficient N for the trees and how would you space them?

    Obtw, I have planted wisteria and its cousin trumpet vines.  Both are invasive as hell.  They spread by roots and I have been unable to rid myself of them.

    Doug

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  • Sun, May 10, 2015 - 12:12pm

    Reply to #3

    Oliveoilguy

    Status Silver Member (Offline)

    Joined: Jun 29 2012

    Posts: 521

    sunn hemp

    [quote=robie robinson]

    Sunn hemp, i flash graze about 100 ewes plus lambs 3-5times /summer. corn grows well without fert. every 3rd year

     

    its baahhd stuff

     

    http://www.petcherseeds.com/about-sunn-hemp/

     

    obtw, as a long time farmer, hairy vetch, austrian winter peas, white clover,alfalfa, sunn hemp, and $#!t/manure are about all i need. ruminants of course. now to get that mare bred so oil will be of even less value than…

    [/quote]

    Thanks Robie for the link to Pretcher Seeds. Will deer and horses eat the sunn hemp as it comes up? Also I assume it will be killed by first frost?  Do you disk it into the soil?

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  • Sun, May 10, 2015 - 4:37pm

    #6
    robie robinson

    robie robinson

    Status Gold Member (Offline)

    Joined: Aug 25 2009

    Posts: 868

    deer will esp. its a popular game feed

    a huge amount of biomass. there was about 3 acres of it across the road when you were here. I've never baled it, only grazed it. Horses I imagine would eat it to the ground if given enough time. Sheep flash graze it several times a year. after discing in i plant fall brassicas also for sheep. it will definitely winter kill and i've never had any self seeding into the next season. i have had corn, sorghum, buck wheat, etc other summer annuals throw sufficient seed to come back the next year. not sunn hemp. it is ALOT of biomass. ie. after a sheep graze of several days it is solid green sheep manure and hemp stalks. it also must have alot of moisture because the sheep drink no water when in that paddock eventhough it is freely available.

    check out april 6th on this blog:   http://www.annasatalinophotography.com/blog/

    "God whispers to us in our pleasures, speaks in our conscience, but shouts in our pains: it is His megaphone to rouse a deaf world." C.S.Lewis

     

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