What Do Plants Need to Grow?

What Nutrients Do Plants Need To Grow?

As a soil scientist writing to you from Tucson, Arizona in the Desert Southwest, I'd like to talk with you today about three of the 17 essential plant nutrients that all plants require in order to grow normally, and those three are carbon, hydrogen and oxygen.

How Plants Absorb Carbon

Carbon is absorbed by plants from the air in photosynthesis, and they absorb carbon dioxide molecules. But the plant cannot grow with just carbon dioxide. It has to split those molecules so that the carbon atoms can be attached to each other, and they liberate oxygen in the process.

Sources of Water for Plants

The other two elements are oxygen and hydrogen, and most plants get their oxygen and hydrogen in water. And so when we think about irrigating, or we think about rainfall, we're thinking about the sources of water for plants, namely hydrogen and oxygen, H2O, that is required by the plants.

What Is the Chemical Makeup Of Plants?

Now, if we take a plant, like this cholla cactus here, and we just completely dry it out, about 45% of the weight of that plant will be carbon, about 45% of the weight of the plant will be oxygen, that's 90%, and maybe 6%, more or less, would be hydrogen in the compounds of the dry matter of the plant. Now, these three elements, which come from the air, carbon from the air, and then hydrogen and oxygen are absorbed by the roots as water and then split in photosynthesis, do many things for the plant.

What Nutrients Do Plants Gain Through Photosynthesis?

basics of plant nutrition

The carbon-carbon bonds are where we store solar energy that the plants capture in photosynthesis, and the hydrogen and oxygen that come into the plant as water, maybe about 10% of that water will remain in the plant. But the rest goes out of the plant and cools the plant. So when water is transpired, or comes out of the plant, it drops the temperature of the plant maybe 10 degrees, so it acts as an evaporative cooler. The water that remains in the plant gets split up, and those hydrogen and oxygen atoms are attached to carbon atoms giving you the basis for building all of the compounds in the plant.

That's our little glimpse at plant nutrition today.

If you have further questions about carbon, hydrogen, and oxygen and their roles in the plant, contact me here at my website Globalagronomy.com.