How to switch from Jacks
So you want to switch from Jacks and start mixing your own? Here’s how:
To use Jack’s, you would normally need 3 ingredients - Jacks, calcium nitrate and epsom. You will keep the calcium nitrate and epsom, as those are your main supply of calcium and magnesium.
Jacks is made up of epsom and 3 additional ingredients, plus micros. Those 3 ingredients are:
- Potassium nitrate
- Potassium sulfate
- Potassium phosphate (MKP)
For the micronutrients, I recommend the plant prod chelated micros.
If you want to keep it simple, use:
- 1g potassium nitrate
- 1g potassium phosphate (MKP)
- 0.3g potassium sulfate
- 0.2g plant prod
= 2.5g per gallon
To this, include:
2.5g calcium nitrate
2.5g epsom
I call this the 2.5-2.5-2.5:
Here are the ppm numbers:
Very similar to Jacks, and roughly 1.8EC. If you want to make it in bulk, just follow the 1:1:0.3:0.2 ratio. Mix it together and apply as 2.5-2.5-2.5
However, the power in leaving it unmixed is that you can now tweak the recipe as you like, without having to buy boosters or other amendments. All you need to do is change amounts between those 3 ingredients. Want less nitrogen? Try swapping the amounts of potassium nitrate and potassium sulfate. Want more phosphorus? Take out the potassium sulfate and add it to the potassium phosphate.
As long as you keep the amounts roughly the same, you can just switch between the different anions as you like. And since sulfur has a low requirement and a very high toxicity limit, you don’t need to worry about how much or how little you are providing.
Since P is an essential nutrient, and only provided by MKP, you can use as little as half the amount shown above (0.5g=30ppm). Keep it above that amount, and the rest is your oyster. You don’t need a calculator to do this. Make the 3 ingredients add up to 2.3g, and keep the MKP above 0.5g. Use your intuition to decide the rest. More N in veg, less in late bloom. More P in early flower. Have fun with it.