Help with switching to Jacks fertilizer

[Dirt_Wizard]

This is another good pair of posts to read from Dr Salts

About Jacks

Lefthand's Synthetics from Scratch

Synthetics not from scratch I’m going to make a more lengthy answer to your question, because it’s more complicated than just NPK ratios. I’m glad you asked it and are interested in experimenting as I am. I am learning a lot of things about nutrient solutions this year as you can see from this pretty lengthy thread, and I think I am at a point where I can explain some things that should give you guidance. I’m calling this ‘not from scratch’ because if you’re using a premixed formula like 5-12-2…

About NPK and PPMs

Lefthand's Synthetics from Scratch

[image] First thing to know is that NPK in the US is given as N, P2O5 and K2O. If you want to get ppm of K, you need to use a conversion factor 0.83. Next thing you need to know is that ppm is the same as mg/L. So now you just need to do the conversion from NPK and g/gal into mg/L. 26 = 26% K2O = 0.83 * 26 = 21.58% K We use 3.7g/gal, and 21.58% is K, so 3.7 g/gal * 0.2158 = 0.798 g/gal (ie 0.798 grams of K per gallon) Now convert g/gal into mg/L (ie ppm) 0.798g/gal * 1000mg/g * 0.264 gal/L…