The Kratsky Method is a simplified hydroponic system in which the plants are suspended above a reservoir containing a nutrient solution. The solution goes down over time as the plant uses up the water and the nutrient, and as the level decreases the roots grow down to access more resources. This is just a brief introduction and for those interested it is recommended they properly research the method before doing it, as with any technique.
The fertilizers used with it are relatively simple, consisting of a 4-18-38 blend, Calcium Nitrate, and Epsom salt. In Canada the 4-18-38 blend is not available and those wanting to use this method often run into issues figuring out a proper feeding program. The great news is that using a 3 part system offers huge amounts of flexibility, as changing the ratios can allow for the replicating of all but the most extreme feeding programs.
We looked at the amount of each individual nutrient that this feeding program is providing the crop, and then made adjustments accordingly. This is what we recommend:
Per 4 liters (gallon)
7 ml Holland Secret Grow
7 ml Holland Secret Micro
7 ml Holland Secret Bloom
It is a lucky coincidence for anyone interested in using this that all of the components came out equal, as the products will all be consumed at the same rate.
For those people who are using the Kratsky method on tomatoes, we recommend supplementing supplementing with a Calcium Magnesium supplement like Calnesium or Organical Magic since tomatoes have a high demand for Calcium. Do not add to the initial solution since the solution may be too strong for a young plant, but rather once flowering begins. Add at a rate of 8 ml per 4 liters (gallon) for the remaining volume and not the initial volume.
As with any hydroponic method, remember to always keep a close watch on pH and TDS levels. This is especially in the case of hot conditions as water can quickly evaporate and render the solution too strong which can damage the plant.