Mary's Veggie Garden

June 23, 2014


Filed under: Beans,Gardening,Vegetables — marysveggiegarden @ 8:49 pm

When  I thinned my pole beans last week, I was pleased to find the roots loaded with rhizobia nodules.  Yes, this is a good thing.

Rhizobia nodules on pole bean roots.

Rhizobia nodules on pole bean roots.

See all those spherical nodules? Each is home to rhizobia bacteria. The rhizobia and beans have a symbiotic relationship: the rhizobia take nitrogen from the air and convert it to a form the plants use as fertilizer. In return the beans feed the rhizobia and house them in the nodules.

At planting time I inoculated the seed with rizobia using a general purpose bean and pea inoculant. It’s working!

BTW when I thinned the plants I should have snipped them instead of pulling. After snipping the roots, nodules and their rhizobia and fixed nitrogen remain in the soil, to benefit adjacent plants.

Harvest Monday: I’m currently harvesting lettuce, spinach, kohlrabi, snow peas, snap peas and Napa cabbage.


  1. I went out of my way to purchase the inoculant this year as well – now I’m waiting to see if it makes a difference in the crops. Last year, I did pull a few bean plants from the ground & some had a few nodules (nowhere near as big as yours), while others didn’t. It will be interesting to compare with this year.

    Comment by Margaret — June 24, 2014 @ 1:11 pm | Reply

    • I’ve never done the comparison so I’m interested in your results. I figure that if I have inoculant, I may as well use it. My beans and peas always do quite well. We are still eating last years beans from the freezer.

      Comment by marysveggiegarden — June 24, 2014 @ 3:02 pm | Reply

  2. I inoculate my beans and peas too. Though I don’t always see rhizobia when I pull.

    Comment by daphnegould — June 24, 2014 @ 2:50 pm | Reply

  3. So do you add innoculant each year or do you find the bacteria persists once it is established in the soil?

    Comment by Ali — June 25, 2014 @ 2:08 pm | Reply

    • I add it every year, it is easy fertilization. Inoculant usually expires after one year, and I use about half a packet a year, so I use the second half after its expiration date. I haven’t noticed any difference using ‘old’ inoculant.

      Comment by marysveggiegarden — June 25, 2014 @ 2:53 pm | Reply

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