Adding Nitrogen to Your Soil Naturally – Nodulation on Plant Roots

Q.  I’ve been told I should inoculate my bean seeds. Why should I do this, and how do I do it?  Does alfalfa need it?  Any others?

A.  Why Use Rhizobia Inoculants? Rhizobia bacteria are a group of soil based microorganisms, which establish symbiotic relationships with beans and other legume plants, such as alfalfa and clover. They then form nodules on the roots of the legumes, where they store nitrogen and provide it to the plants. In return, the plants provide carbon and energy for the Rhizobia, which the plant produces by photosynthesis.  Nitrogen is vital for plant growth.  It is abundant in the atmosphere as N2, and in soil organic matter in other forms, but because of its volatility, it is not available in the NO3 form that plants can use.

Conventional methods of providing nitrogen to plants include 1) adding nitrogen fertilizers to the soil, or 2) inoculating with the Rhizobia nitrogen-fixing bacteria. Rhizobia then take N2 atmospheric nitrogen and convert it to the NO3 inorganic form that is useable by plants. In addition, the nitrogen they store in nodules on the plant roots, if the roots are left in the ground, can reduce nitrogen fertilizer requirements for the next growing season. 

Therefore, before planting, some gardeners “inoculate” their bean seeds.  This consists of coating the seeds with a small amount of powder containing the Rhizobia bacteria, thus effectively enabling the plants to draw nitrogen from the air and deposit it in nodules on their roots. This ability to “fix” nitrogen is unique to plants in the legume family, because of the symbiotic relationship with Rhizobia bacteria. 

Inoculants only need to be used in poor soils that don’t have much soil nitrogen for plants to use. In fertile soil, the bacteria occur naturally, so inoculants are not needed. The inoculant comes in small packages, it is usually available where you buy your seeds, and it takes very little to do the job.Immediately before planting, put the bean seeds in a pan and add a little water to moisten them. Then add a small amount of inoculant, and stir the beans with a stick until they have a little powder on their seed coats.

To gain the maximum benefit from inoculating your been seeds, spade or till disease-free bean plants into the earth immediately after the last harvest. This adds organic matter to the soil and releases the nitrogen from the root nodules as well.   Always destroy all diseased plants immediately. 

Some people mistakenly believe planting beans and corn together is good, because the beans can climb the corn stalks, and the corn can get nitrogen from the beans.  This is not a good idea for several reasons.  The two plants are competing for the same water, food (13 nutrients are needed!), and light, and both will suffer for having to share.  In addition, the nitrogen in the bean root nodules is “fixed” and unavailable to the corn. It is only released to the soil after the bean plant has completed its life cycle.

How to Grow the Healthiest Vegetables

Q.  I want to grow the healthiest vegetables possible. Isn’t organic gardening healthier than the Mittleider Method – tell me the truth!

A.  This is a very good question and it deserves a straight answer. I will therefore tell you some very important things about plant nutrition. First of all, plants receive nutrition only as water- soluble mineral compounds, through their roots. When we put compost or manure, etc. into the soil, the organic material must first decompose, and the nutrient compounds must revert to water-soluble minerals before the next generation of plants can use them. This takes time, and sometimes as much as half of the nutrients are lost in the process.

Secondly, there is no difference between organic, mineral, and chemical nutrients.  Everything in this world is a chemical!!  To the chemist everything in the soil is called chemicals, to a geologist they are called minerals, and to an organic enthusiast they are called organics, but they are the same substances.  To quote J. I. Rodale, “we organic gardeners have let our enthusiasm run away with us. We have said that the nitrogen which is in organic matter is different (and thus somehow better) from nitrogen in a commercial fertilizer. But this is not so.” And “actually there is no difference between the nitrogen in a chemical fertilizer and the nitrogen in a leaf.” (Organic Gardening)

Thirdly, there is no difference between soil and rocks except for the size of the particles, and 12 of the 13 mineral nutrients plants require are essentially ground-up rocks! There is really nothing “synthetic” about them.  So, you see there is no difference between “organic nitrogen”, mineral nitrogen and chemical nitrogen – except the nitrogen that is part of an organic substance must decompose and revert to the water-soluble mineral state before being available to plants.

This being the case, what should we do to assure we have the best garden and the healthiest plants possible? Give the plants the best combination of nutrition we possibly can.  Remember that 99% of us depend on 1% to feed us, and the big growers feed their crops! The big fertilizer companies use formulas similar to Dr. Mittleider’s and call them “The preferred horticultural mix.” Just check out Scott’s Peter’s Professional Pete Lite as an example.

Now, this is not to say that organic materials don’t have a place in the garden. You can improve soil texture and tilth by adding materials that have desirable characteristics.  However, improving the soil in that way is not necessary to having a good garden, and people often introduce weeds, rodents, bugs, and diseases into their gardens, or provide a haven for them with their organic mulching practices. It is for this reason that we do not emphasize and encourage composting and manure. 

Mittleider gardens qualify as “organic” because we don’t use pesticides or herbicides.  However, I suggest they are even “better than organic”, because the plants receive just what they need, they grow fast, and we almost never have insect or disease problems because they aren’t in the ground long enough for the pests to get established.

Some Veggies in my Grow-Boxes look pale

Q.  Some veggies in my Grow-Boxes look pale. These were transplanted on 4/15/ and fertilized with 21-0-0 three days later. Other than that I have been doing the weekly fertilizing. Can you let me know how to help them. One of the cucumbers died already, the rest look pale and wilted.

A.  Cucumbers and other melons and squash should not be planted until the weather is warmer – after May 15, in Salt Lake City. They do not do well in early spring.  Nitrogen should be applied immediately at the time of transplanting, and three days later Weekly Feed should be applied.  21-0-0 is not nearly as good as 34-0-0, especially in cool weather, because of the composition (NH4 vs NH3). NO3 is immediately available to the plants, while NH4 must be changed to NO3 in the soil before the plant can use it.  Did you put the proper Pre-Plant fertilizers in the soil before planting?  Fertilizing should begin after the plants come through the soil, however you must be careful not to get the fertilizer on the plant stems or leaves.  Fertilizers are salts, and will burn any plant if applied directly.  Apply four inches from the stems and then water in thoroughly.