Nutrient solutions

Nutrient solutions

Bram Steiner passed away recently, on the 1st of March 2016 at the age of 95. He was one of the founding fathers of hydroponics in horticulture. He fought for years to keep alive the research on soilless techniques when nobody believed in them; he was ridiculed for his ideas. In the early sixties he stated that the chemical composition of a nutrient solution depends upon the concentration of the composing ions, on the total ion concentration, and on acidity expressed as pH. We are doing a couple posts on nutrient solutions in his honor. Thank you Bram!
Now that 3D printing and nano-machines are all the rage, let’s remember that plants do 3D print themselves at nano scale everyday. They take all the atoms that constitute their tissues from their aerial and root environments and assemble them to grow. They need to have those building blocks at hand, though.
In addition to carbon (C), hydrogen (H) and oxygen (O), which they take from the air, plants need other mineral elements to grow and complete its cycle. In natural ecosystems, the minerals absorbed by plants return to the soil after organic matter decomposition and become available again. In the hydroponics system, however, all the nutrients are supplied by the nutrient solution. Growers routinely control the overall quantity of ions contained in the solution by measuring its electrical conductivity. In fact we would like to know how much there is of each ion. That is actually quite difficult; the only practical thing we can do is to use a well balanced nutrient solution, with a bit of everything in just the right quantities.
Depending on how much they need, the elements of the nutrient solution are divided into macronutrients (plants need large amounts) or micronutrients (very small amounts).

• Primary macronutrients: These are what plants need the most, and should always  be part of our nutrient solution:
  • Nitrogen (N)
  • Phosphorus (P)
  • Potassium (K)

• Secondary macronutrients: These are usually on the ground itself,  and some waters also contain Ca and Mg, but in hydroponics we cannot rely in minerals in the soil, so we need to make sure that these are included in the nutrient solution as well:
  • Calcium (Ca)
  • Magnesium (Mg)
  • Sulfur (S)

• Micronutrients: Just like humans need some trace elements to live, plants also require some minerals in tiny amounts to grow healthy. Without them the plants will not develop correctly. Some of them are better absorbed in chelated forms, which are like organic containers for the ions:
  • Iron (Fe)
  • Manganese (Mn)
  • Boron (B)
  • Molybdenum (Mo)
  • Copper (Cu)
  • Zinc (Zn)
  • Chlorine (Cl)

• Beneficial nutrients: In addition to macro and micro nutrients, there are other elements that are not essentials for all crops, but may improve plant growth, health and yield. However, be careful because the essential-to-lethal range for these elements is somewhat narrow. A holistic approach to plant nutrition should include these elements at levels beneficial for best growth:
  • Aluminium (Al)
  • Cobalt (Co)
  • Sodium (Na)
  • Selenium (Se)
  • Silicon (Si)

So you want to grow the best crop, you should know your fertilizer. There are a lot of solutions in the market ready to use for different crops.  Although they are a little expensive, they are perfect if you haven’t got a lot of knowledge or time. It is cheaper and not so difficult to  buy fertilizers as a powder that you mix with water to use. The hard but cheapest way is to make your own nutrient solution from salts. We will tell you how to do that in the next post. Prepare your lab!