Mixing and manipulating NPK #s?


Well-Known Member
In the quest to learn more about the growing I’m doing.

im trying to understand the NPK ratio a bit better.
Research shows the general consensus on NPK ratios for cannabis in Veg are 3-1-2 and for flower are 1-2-3.

I’ve been playing around calculating/adding NPK numbers together in their ratios to find out what the NPK of my final feed solution comes in at.

on paper I am finding that following bottle mixing instructions. NPK values are all over. Not following the 3-1-2 or 1-2-3 guide line.

Should I be tweaking mixing ratios to get to the final NPK I’m looking for? Is that how you track your formula?

now to make sure I got this right.
For a example of what I’m doing.

Take the Lucas Formula with GH trio.
standard mid is 8ML Micro and 16ML bloom /GAL. Right?
that’s 1:2 ratio.
micro NPK 5-0-1
Bloom NPK 0-5-4

should give me a complete NPK of 1.65 - 3.3 - 2.97 for my feed mixture right?

Safe to say that is a proven formula?

If you could replicate that NPK ratio or pretty dam close, using other manufacturers fertilizers would that be a safe road to go down?


Well-Known Member
You can mix chems to adjust npk, but remember to keep your high n mix during the stretch after switching to 12/12


ok in this case i wouldnt use these ratios
ideally you want around 4-3-5 for vegetative, and 4-3-8 for bloom
you start the bloom formula when you switch to 12/12 and start to add a booster (pk 13/14) around week 2 when buds are forming (slowly)
more you go in the flowering stage more pk you add to the mix

Nitrogen discourage buds formation but you need it until the end or you will get yellowing, senescence ( yellowing) will kill your yield and your aromas, your plants must be perfectly healthy from the start to the end, thats how you get best yields and terpenes production

if it can help you i use ionic 1 part grow/bloom for soft water with RO water (mainly condensate water from AC units and dehumidifiers) and it works perfectly for hydro
ionic bloom soft water is npk 3.1-1.9-5.9
it designed to use with a bit of ph up (potassium hydroxide) or potassium silicate ( for veg)

mixing your own nutrients is a great challenge but a bit a headache and a loss of time if you want my opinion, 1000s of things can be improved before homemade nutrients mixing, let professionnal companies do it