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[Food For Thought] Nutrient Ratios & Relationships (Part 3 of 3)
Getting your NPK dosage right is about more than just your nutrient strength. It's also about your nutrient ratio.
This is part 3 of a 3 part series into plant nutrition. Here you'll find out about nutrient ratios and relationships.
- Part 1 - What and When to Feed
- Part 2 - Primary NPK Macronutrients
- Part 3 - Ratios and Relationships (this article)
NPK ratio
Plants need N, P, and K.
BUT the amount of each varies, depending on your stage of growth (and other factors).
That's why you have specific 'grow', 'bloom' and 'baby' formulas.
Grow Nutrients: are high in N & P
Bloom nutrient: are high in P & K
'Baby' plant nutrients: are very high in N and a bit higher in K than 'grow' nutrients
Coco nutrients don't have 'grow' and 'bloom' variants. Why? Coco likes to hang onto Nitrogen, but release Potassium, so coco feeds are different.
Using Boosters and Additives
When you use boosters and additives, you're not just adding more nutreints. You're also changing your nutrient ratios.
For example:
PK boosters are high in Phosphorus (P) and Potassium (K).
Add them to your feed, and you'll widen the N:PK gap.
That's why we recommend adding a PK booster from week 4 of flowering. At this time, vertical growth stops, so they don't need as much Nitrogen. Plants also start forming their initial flowers - a bit of extra P & K ramps this up!
What's in my reservoir?
When mixing nutrients and boosters, it takes some work to calculate your new NPK ratio!
For each nutrient and booster, you will need to:
- Find out the NPK ratio
- Calculate the dilution factor
- Nutrient concentration / dilution factor = % in nutrient solution
We'll show you how to do it with SHOGUN Samurai Hydro Bloom at 4ml/L dilution rate
Find NPK ratio
Your NPK ratio should be displayed somewhere on your bottle.
SHOGUN Samurai HydroBloom has an NPK ratio of 4.13 / 3.46 / 6
Get Dilution Factor
There are 3 steps:
1. swap dilution rate:
1L / 4ml
2. covert L to ml ( L x 1000):
1000ml / 4ml
3. Do the calculation:
1000ml / 4ml = 250 dilution factor
Calculate NPK in solution
Nitrogen / 240
4.13 / 250 = 0.01652
Phosphorus / 250
3.46 / 250 =0.01384
Potassium / 250
6 / 250 = 0.02400
NPK in solution: 0.01652 / 0.01384 / 0.02400
Repeat that process with every nutrient and additive you're using.
We also did if for SHOGUN PK Warrior and got 0 / 0.00450 / 0.00900
Add the two together:
SHOGUN PK Warrior: 0 / 0.00450 / 0.00900
SHOGUN HydroGrow: 0.01652 / 0.01384 / 0.02400
You get: 0.01652 / 0.01834 / 0.03300
By adding PK warrior, you now have almost twice as much potassium as you do nitrogen.
