Inoculum for Legumes

Inoculum for Legumes

Choose from 17 different rhizobial inoculum strains including Baptisia, Dalea, Lupinus and many more. 1 bag will inoculate up to 1 pound of seed.  

Most legume species harbor beneficial bacteria called rhizobia on their roots. Genus-specific strains of this bacterium called inoculum can aid in the fixation of atmospheric nitrogen and improve long-term health of native plant communities, especially in low fertility soils.

HOW TO USE: Add inoculant to dampened seed and mix thoroughly.
WHEN TO ADD: At time of cold, moist stratification, or if direct seeding, as close to planting time as possible.
SPECIAL CARE: Protect inoculated seed from sunlight or drying winds - cover seed as quickly as possible with soil or mulch.
ALTERNATIVE METHODS: Inoculant can be mixed with potting soil when planting in flats or peat pots; directly in the seed furrows along with seed at time of transplanting; or to potted plants by making a hole with a pencil. Inoculum may also be added to potting mix for container grown plants or into the bottom of a hole when transplanting container grown or bare root seedlings.

5 Questions asked on Inoculum for Legumes

Q Chris DeRhodes • April 5 It is effective to apply inoculum to seedlings that have already sprouted in indoor containers? What about something like an existing Baptisia plant growing outside that was planted in post-construction exposed subsoil of questionable quality?
A Prairie Moon • April 8 Thanks for writing, Chris. The bacteria in the inoculums that we carry for legumes typically are already present in most healthy soils. They do not affect plant germination but do establish symbiotic relationships with developing roots to enhance the formation of nodules that absorb atmospheric nitrogen. Adding inoculum to soils is an effective way to introduce or increase the population of beneficial bacteria.
Q Maggie • June 6 Hello, do you offer inoculum for Thermopsis? Thanks!
A Prairie Moon • June 6 Hi Maggie! We do! It's the same as the Baptisia Inoculum.
Q Pam • August 7 How do you choose the best type of inoculum for your soil? Are certain inoculums better for specific plants or seedlings?
A Prairie Moon • August 11 Hi Pam. You really only need to consider purchasing inoculum if you are ordering Legume species - those in the pea family. This Inoculum order page lists the various legume genus', or you can find them by typing 'legume' in the search bar.

If you have very degraded soil, perhaps all organic matter was stripped off from construction, then you could consider our Mycorrhizal Inoculum for Exposed Subsoil, sold by the lb.

Q Olivia • March 10 Does the inoculum keep well for future seasons? Due to variety of species, I’ll need to buy much more than I can use in one season.
A Prairie Moon • March 11 Hi Olivia, Good question! If kept refrigerated, the inoculum will stay viable for at least a year, probably a bit more.
Q Daniel • August 3 I have a few legume species that I would like to direct seed this fall (Amorpha, Chamaecrista, Lupinus). The soil is not the healthiest and has only been lawn. Would you recommend a separate inoculum for each species, or would one inoculum work for all?
A Prairie Moon • August 4 Hi Daniel, Different genera of legumes tend to make associations with different strains of nitrogen fixing bacteria. In most instances this bacteria will be present in the soil, but if you are worried about the quality of the soil, you should get the three appropriate strains for each genus.
*PLEASE NOTE: we are a mail order nursery and have no retail facilities, but you may pick up your order if prior arrangements are made. Pick up orders are subject to 7.375% MN Sales Tax.

Shipping & Handling Charges

TOOL SHED and BOOKS have the shipping fee included in the cost of the item. In other words, they SHIP FREE!

Shipping Season

SEED, TOOLS and BOOKS are sent year-round. Most orders ship within a day or two upon receipt.


We ship using USPS, UPS and Spee Dee.



Catalog Number