tl;dr: Jacks 321
Below are instructions for feeding your girls however, in the absolute, you should know that plants only require three basic nutrients, Nitrogen (N), Phosphorus (P), and Potassium (K), often seen as NPK or some concoction of a three-number array. We strongly believe Oxygen (O) to be the fourth basic, but since nobody has figured out how to charge for it (actually, see air pumps), we’ll focus on the big three.
Pro Tip: #dontbuywater
Without getting too technical, our suggested nutrients are the same ones used by commercial hydroponic grow operations for food production Linked is Jacks 321, which is reduced weight and size and is perfect for our grows using a five-gallon bucket as the reservoir that serves four plants. Typically the nutrient is sold in large bag quantities, which in our systems would last forever. I haven’t done the math, but a typical grow is 13 weeks, and you’ll get more than three grows or more out of this package, so kudos to whoever takes the time to break it down.
Understanding basic plant requirements should force you to abandon purchasing liquid nutrients as you are just paying for water.
The best advice for starters is to focus more on environmental conditions and less on expensive nutrients. In our experience, oxygenating the root system produces #rootporn.
Doing Jacks 321 in a 5 gallon
This three part is simple as long as you get a scale which removes any guess work. Label 3 red solo cups with a one two three. Nutrients are applied to the system from seedling until chop. Seedlings give enough time (about a week – they can go longer) to use the nutrients provided at birth.
Next label one with xyz 18g, two xyx 12g, three
1. 18g 5-12-26 (fine)
2. Epson salts – 5.5g (course)
3.12g Calcium Nitrate (in-between)
For some reason the order matters however for our system we run the pump while recirculating the nutrient solution and giving the plants a nice breather.
Every Deepwater culture system requires nutrients to be changed weekly and especially during the flowering cycle. Pay attention to weekly nutrient changes while using Jack’s 321 and you’ll start to believe you actually know what you’re doing.
5-12-26 – 18g (3.6g/gal)
Epson salts – 5.5g (1.1g/gal)
part b calcium nitrate (12g 2.4g/gal)