Good morning all
I thought I would pop in and offer some extra information concerning the organics many of us are using/converting to.
Many growers have been conditioned to think in terms of hydro and/or traditional greenhouse methods, although nutrient uptake is similar in all grow methods, it is the nature of the nutrients provided that is different.
Having come to this hobby late in life (both growing and using cannabis), 45 yrs old to be exact, I had no preconceived notions of soil and plants. Wanting to grow organically from the outset, and having a background in chemistry and biology (from my engineering studies) I dove straight into the science of soils and how they support our plants.
We all know what NPK is, but many do not realize the scientific difference between organic sources and traditional sources.
I am sure many have heard others, maybe even experienced it themselves,talk of nutrient burn. A "burn" in its simplest definition, regardless of whether its from heat, chemical or some other reason, is the de-hydration of tissue. Nutrient burn is the de-hydration of plant tissue, and this only occurs in methods that use "salts" as a nutrient source. A "hot" soil, has excess nutrient salts in it.
Now I said you can't cause nutrient burn with organic soils, which is true, but you can still burn your plants with organics if you don't "cook" the soil long enough. This is because as the organic matter breaks down, it creates heat, enough so that it can literally "cook" your plants. As a general rule, cook your soil in a pile, container, whatever, until you can put your hand into the center of the pile and it feels cool to the touch. Once the center is cool, you can use the soil without concerns of burning your plants.
As Bob mentioned above, mix humus in with your soil. Humus is full of micro-nutrients and has great exchange capacity.
To give you an idea, the CEC of coco is about 100 meg/100mg, peat is 100-200 meq/100mg and humus is 100-300 meg/100mg. The higher the 'meq' the greater the number of sites for nutrients that are available to your plant, meaning faster, healthier growth.
Don't be overly concerned about over doing it with amendments. Unlike salt based nutrients,which are immediately available, most amendments you will be using will require 4 months or more to completely break down. So long as your soil is cool when you use it, your plants won't burn.
Now a note on perlite. If you are using plastic pots to grow in, then I highly recommend using it to aid in aeration. On the other hand, if you are using fabric pots, then it is not required. Fabric pots (most types) breathe well, allowing good oxygen exchange into the soil, and perlite takes up space while offering little to plant growth as it has a low CEC.
