Here is the first of a series of posts on plant nutrition. The following is published with permission of Hydroponic Unlimited http://www.hydroponicunlimited.com/ This website and the website owner have been very forethcoming with hydroponic system design and advice, nutrients, maintenance, and all-around hydroponic information.
Plant Nutrients and how they are used
For testing purposes, plants are generally dried before testing. 80 to 90 percent of almost all plants is water.
About 90 percent of the resulting dry matter is made up of only three elements; Carbon, oxygen and hydrogen.
In regards to just these three elements, when you water a plant, it provides the hydrogen and oxygen and more oxygen and carbon come from the carbon dioxide from the planets atmosphere.
What these percentages tell us is that if you break down the wet weight of almost all of the plants on our planet, only 1.5 percent of that plant is made up of the remaining elements that make up a plant.
That 1.5 percent of total plant weight is made up of the 60 elements found in living plants. Of the 60 elements only some are used in each plant or plant type and they are used in varying amounts, depending on the plant type and conditions.
The elements that make up this 1.5 percent of plants have a major impact on the health and harvest of the plants. If only one of all the elements used in a plant is missing, it can quite literally kill the plant. On the other end of the spectrum, if too much of some single elements are used, it can also kill the plant.
This is why feeding a plant in a way that is balanced for that particular plant is so necessary.
Of the 60 elements found in almost all plants on our planet, only 16 of the elements are considered to be essential for growth.
In order of the percentage of each element in the dry weight of most plant matter:
45% = Carbon
45% = Oxygen
6% = Hydrogen
1.5% = Nitrogen
1.0% = Potassium
0.5% = Calcium
0.2% = Magnesium
0.2% = Phosphorus
0.1% = Sulfur
0.01% = Chlorine
0.01% = Iron
0.005% = Manganese
0.002% = Boron
0.002% = Zinc
0.0006% = Copper
0.00001% = Molybdenum
This article was originally published in forum thread: http://www.hydroponicunlimited.com/content.php?20-Plant-Nutrients-and-how-they-are-used] by Hydro-1
Thanks Hydro-1. As always, you have been very helpful!