First time growing hydro seedling ppm levels?

These are the nutrients im going to be using. You see where it says target ppm level 500 , and 700? Week one it says 1000 on the 500 one, and 1,400 on the 700 one. I’m confused on what that means why is there two? Shouldnt all of the measurements add up to one ppm? And im used to growing in soil and coco. 1,000 and 1,400 seems extremely high ppm.

I am doing flood and drain for the first time. Any advice? The guy at my grow shop didn’t have anything covering the res, but his plants turned out beautiful. How critical is it to have the bottom part covered up to prevent algae and stuff? Any info is appreciated, im just really woundering about good starting ppm. And should i do half strength starting out like you normally do in soil and coco with most nutrient lines? Thank you guys.

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welcome to hydro…there are 2 scales for ppm levels not sure why exactly but USA uses the 500 scale I remember correctly…
quote=“Beeken1992, post:1, topic:106357”]
I’m confused on what that means why is there two?

very important to not let light into your root area

most will tell you yes…the plant uses light for the real food and all the nutrients we add are more like vitamins IMHO


Your meter only measures EC, it can’t measure actual Parts Per Million. It calculates PPM off the EC reading, depending on what scale it’s using (there are at least 3) and you need to know what scale your meter is using if you want to understand what PPM to use.

It’s just way easier to stick to EC instead of any TDS readings imho, and that chart also lists EC.


Awesome thanks guys. I just got a ppm meter off of amazon. I did notice though every ppm meter ive gotten was off by like 80 ppms when it got up to around 900. Even when ive bought the same exact meter.

Is 2 ec not high for a plant in hydro though? I feel like it’d fry them. In coco i started out with like 300 ppm

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Would depend on the nutrient being used. Im not a true hydro guy but i do run coco with a res. I would feed full strength jacks at around 2.1 ec. No ill effects and in tbe seedling stage. 2.1 ec at 500 is 1050 ppm, or at 700 scale is 1470 ppm.


:point_up_2: 2.0 is 1000 PPMs on the 500 scale and is what I run in Hydro, coco or soil. PH is the same for hydro and coco 5.8-6.2 range :love_you_gesture: