The Wonderful Legume! Nature's nitrogen fixer and fertilizer you can eat.

Beans beans, the magical fruit…

Have you ever started a new bed or a new garden only to be vastly disappointed with the general shabbiness of the growth? You’ve watered it the right way, given it plenty of sunshine. Maybe you even sang to the plants. Yet still, somehow, nothing really takes off the way it should.

One of the causes could be the quality of your dirt. We must always mind our dirt! It may be devoid of the proper levels of nutrients needed for healthy happy plant growth. If you want your plants to grow big and strong, one of the best ways is to give it nitrogen! Plants are like people, they love water, fresh air and sunshine but they also need to eat.

But what do plants eat you ask? Here’s the big three; Nitrogen, Phosphorus and Potassium. It’s these three elements that are listed (in that order) in a number system on every bag of fertilizer you’ve ever bought. Does this look familiar?


In this example, the Nitrogen is the highest number, so this fertilizer would be best for leaf and stem growth as well as that healthy deep green color. In this bag, we have 32% Nitrogen, 10% Phosphorus and 10% Potassium. I know, you math genius you, that’s only 52%, where’s the other 48%? The other 48% is other nutrients and filler material. The filler material helps to spread out the major nutrients for a nice even dose. But, you can’t eat this fertilizer. So please don’t try!

We can talk more in depth about the benefits of all three elements in another post, but for now I’ll sum it up:

  • Nitrogen is great for plant growth and healthy photosynthesis.
  • Phosphorus is great for building strong roots and to encourage flower and bloom development.
  • Potassium is an all around health boost that aids against disease, drought and cold tolerance.

Now this is all well and good, and you really should get to know these big three elements as well as which plants like more of what. That’s not why we’re here though. We’re here to learn the secret of legumes and how they can give you relatively free nitrogen by the boat loads.

So, what are legumes then?

Legumes have many faces. You most likely know them as beans, peas and peanuts. But did you know that clover are also legumes? So are alfalfa and buckwheat. Also, acacia trees are in the legume family. In fact, you can plant a sacrificial acacia tree in a new bed before planting your main plants as a way to prep the soil. When it grows up a bit, you simple grab it with one hand on top and the other hand can strip the leaves off with one smooth downward motion. Bam! Instant nitrogen! Their leaves are loaded with it. Many farmers will rotate their fields using alfalfa, clover or buckwheat as a way to fix the soil after their main crops have been harvested. They call it green manure.

However, I like to stick with the legumes that I can put on the dinner table. Peas have always grossed me out, ever since I was a wee lad, so I stick with good ol’ fashioned green beans. But how does the magic actually work?

Let’s get all sciency with it!

You see, legumes contain symbiotic bacteria called rhizobia within nodules in their root systems. These rhizobia live pretty much everywhere in the soil. In some places, you need to introduce them by slathering a sticky goo over the seeds before planting. You can buy that online or at a decent nursery. Chances are, you don’t need too though. As the legume grows above ground…

Pole Bean Sprout

…the nodules grow below. Forming on the roots like little tumors of nitrogen yumminess. They look like this…

Legume Root Nodules

Attractive aren’t they? These magical little gems are jam packed with nitrogen in a concentrated little delivery system. So all you have to do after you’ve turned your soil and planted your seeds is let the beans grow grow grow. You can harvest when they are ready and then do one of two things; you can cut the plant down to just a few nodes above the ground and start the process over again, or just let it die. Just don’t pull it out by the roots yet! You’ll ruin the whole magical effect that way. When legumes get so boldly pruned, or they die, the little nodules release their brew. Right into your soil!

Now, when you’re ready to plant you prize Ficus Religiosa, for example, the soil already has at least nitrogen to help it grow big and strong. And as you sit back and enjoy how clever you are, you can enjoy the fruits of your labors…

Pole Beans

Mix a little of your homemade compost or bone meal into the soil as well for the phosphorus and potassium needed for big strong roots and disease resistance and you are on your way to successful organic gardening! The bigger picture concept I’d like to stress here is that you can do this all without using the evil nonorganic fertilizers that pollute the groundwater. It’s cheaper, safer, healthier and also puts food on the table. It’s a win win.

4 Replies to “The Wonderful Legume! Nature's nitrogen fixer and fertilizer you can eat.”

  1. Now this is the most useful knowledge I’ve recieved yet!!

    My youngest daughter (shes 3) just planted a random bean. We watered it an watched it grow. She was ever so fascinated with this process. It took about a month, but it produced 1 bean. She was over the moon about her bean. Showing anyone who would look and telling anyone that would listen.

    Now once that bean began, I took it outside. Left it in its baby pot, gave it a stick to hold on to. The plant turned white. The bean turned brown. I took the bean out of the now brown casing, and put it in the dirt next to its momma.

    Now it is a new bean plant!

    Does 1 bean only produce 1 bean?? This seems weird to me.

    I have just planted 2 pineapple heads. I have about 5 feet between them. From what I’ve learned from this lesson you’ve provided, the bean would be an awesome neighbor for these pineapples. As the pineapples are not gonna give me any fruit till next year. 🙁

    What caused the bean plant to turn white? Lack of food is my thought. But what would you feed it? Nitrogen, phosphorus and potassium is what I just learned here…. but In what qualities and how often?

    1. Beans do tend to get leggy once the fruit sets. Turning white is a new one for me. It could’ve been sun damage or powdery mildew? Typically if it’s a nutrient issue they’ll turn yellow. I’ve never fed beans before but a fertilizer that’s 5-10-10, is good for beans (indicates the fertilizer contains 5% nitrogen, 10% phosphorus and 10% potassium). Nitrogen promotes healthy green leaves and stems, and you don’t need much of it for beans.

      When I sow the beans, I do three beans per hole. They almost always all come up and then I’ll thin all but the strongest of the three. the other two I’ll try to transplant to another location carefully. They are pretty forgiving. They do love climbing so a good trellis of sorts helps a lot.

      The story of your youngest is the sweetest thing I’ve heard in a while. When kids get into growing things, my heart sings!

Leave a Reply

Your email address will not be published.