How Are Nutrients Lost From the Soil?

I get a lot of questions about what fertilizer is the ‘best’ and there is a lot of buzz online about various fertilizers and their myriad of benefits. So, one thing you want to think about is once you add fertilizer, how will they be lost from your soil or grow medium.
The first way to lose nutrients is root absorption. This is what you want, the nutrients to go into your plants to promote growth and increase yield. I have written about factors that can limit growth and good growers know that too many nutrients are just as bad as too few. This Goldilocks factor of biology is why you need to do scientific tests to see what amount of fertilizer you should use. ALWAYS start with the manufactures suggestion; they should have done some tests to give you this starting point. Some plants will do better with a bit more, others may actually grow better with a bit less fertilizer. If you do not get improved growth with more fertilizer, then that can save you money, and prevent nutrient build up over a long time.
   Another way for you to lose nutrients is through leaching. This is when water soluble nutrients are dissolved in water and as the water moved down and out of the pot (or out of the root zone outdoors). Many growers do a ‘flush’ after they are done with vegetative growth; the idea is to wash out any excess nitrogen which can interfere with flowering. This is why you want to waer your plants only when the top layer is dry, so they can use the nutrients in the soil, and you only want a small amount of water to run out the pots when you water. If you notice a white ring on the trays that catch water overflow or on the bottom of your pots, that is most likely salts/fertilizers residue. This is a sign of leaching. Leaching is not a problem with hydroponics since the water is cycled over the roots many times, but you do have to deal with the pH with hydroponics or the nutrients will be unavailable no matter how much you add to the solution. If you are growing outside, another way to lose nutrients is erosion, when pieces of soil are washed away in a rain storm or blown away by wind the nutrients attached to that soil are lost too.

Good Growing,
Dr. E.R. Myers