Simply put, a fertilizer stock solution is powdered fertilizer mixed with water for which the resulting mixture is very concentrated, much like a commercial liquid fertilizer.
Many hydroponic farms have stock solution tanks that will inject the concentrated fertilizer mixture into the main feeding tank.
From a hobby gardener’s point of view, we can make a stock solution so that feeding is easier. Taking a teapsoon of mixed liquid nutrient and adding it to water is easier and quicker than waiting for powder to dissolve. It is also potentially less messy.
Now that we covered those details, we may already know the answer about going about doing this. We take a quantity like 1/4 cup of fertilizer and add it to 1 litre of water. After that, we can just give it a shake and let it dissolve for at least an hour or so, or a day in advance. This solution will be good for weeks to come.
In our case, if we mixed the nutrients of Growlode ‘A’ and Growlode ‘B’ in separate bottles at the previous rate, we come up with a liquid concentration that will will give about 290 ppm each when we mix the liquid at 2tsp/gallon of water.
Thus, if we add 2 tsp in a gallon of water of Growlode ‘A’ and 2 tsp of Growlode ‘B’ in a gallon of water we have a total around 590ppm which is pretty good for spring time growing.
For real young seedlings at 2-4 weeks old, we can get away with 1tsp/gallon of each concentrated liquid.
As plants begin to grow large and fruit, we can bump that up too.
Making a liquid stock solution is quite easy and has obvious advantages. When growing many plants, using a large tank and premixing the desired amount of powder powder in small stock tanks(or even buckets) is a necessity because some fertilizers do need to be mixed separately before adding them to the tank to avoid precipitates.
So, there we have it. We can now take a powdered fertilizer and turn it into a liquid one for a fraction of the price.