Garden for Nutrition Index

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Beneficial Bacteria in Garden Soil

Legume Bacteria That Fixate Nitrogen Non-legume Bacteria That Fixate Nitrogen Other Beneficial Bacteria


Legume Bacteria that Fixate Nitrogen:

Rhizobium bacteria can colonize legume roots and convert atmospheric nitrogen into a form of nitrogen that is useful to the plant. For maximum nitrogen fixation, legumes must be terminated after blooming begins but before seeds begin to form. Seed formation will use up the nitrogen.

Listed below are links which specify which bacteria are ideal for each legume.

Australian Research
University of Hawaii - cross inoculation

Inoculating the soil after planting can be effective.

University of Hawaii - soil inoculation

Some legumes will fix more nitrogen than others. Listed here are links which rank legumes by level of fixation.

NCBI - analysis of fenugreek, faba, vetch, etc.
FAO - nitrogen fixation rankings
USDA Farmers Bulletin 2003 - Legume Inoculation

Australian Society of Agronomy - fenugreek rhizobia
Nitrogen fixers ranked

Some plants have a tendency to form HUP+ bacterial associations depending on the environment. When this occurs, nitrogen does not leak out of the root nodules to become available for the rhizosphere. This may reduce the effectiveness of these plants in intercropping systems; soy, lupine, cowpea, pea, alder, black locust.

HUP+ symbionts

Under reasonable conditions, some rhizobia inoculations survive at useful levels for about 2-3 years without the proper leguminous host plants.

Survival of Rhizobia Without a Host

Rhizobial longevity

Research Review
Endurance of bacteria

Miscellaneous links on the subject are listed below.

FAO - broad research of every aspect
Nodulation examples

eOrganic - rhizobia

Manufacture of Inoculants in New Zealand

Microbial Inoculant - Wikipedia

Non Legume Bacteria that Fixate Nitrogen:

Most of these non-legume bacteria are naturally occurring and are encouraged by grass roots. Research to date has been inconsistant. Instead of buying these inoculums, a better approach may be to simply include grass family members in your vegetable rotation.

Research Gate - bacterial endophytes

ASM - inoculation has no effect or is inconsistant

Auburn - Pseudomonas and Bacillus for vegetables

Genetically Modified Bacteria


Other Beneficial Bacteria:

Links to general bio-control research:

History of Modern Biotechnology - growth stimulants

EPPO - bio-controls


Streptomyces lydicus:

Streptomyces lydicus is a saprophytic Actinomycete which suppresses harmful fungus. Especially useful on okra against cotton root rot. Originally isolated from flax roots.

Bacteria for plant growth promotion.


Chitin is a compound found in shell of crab, lobster, shrimp, snail, fish scale, etc. It will encourage Streptomyces lydicus which will suppress harmful fungi.

Science Direct


Azospirillum brasilense:

Azospirillum brasilense stimulates nutrient uptake in plants.



Crown Gall:

Agrobacterium radiobacteria - prevent crown gall

Agrobacterium radiobacteria - Pacific Northwest crown gall


Mycorrhiza helper bacteria (MHB) examples: Ralstonia basilensis, Bacillus subtilis, Pseudomonas, Streptomyces, etc.


Garden for Nutrition Index