PPM Ratios need some guidance

[Trimmings426]

What's up GWE? Just purchased a ppm meter/ ec meter/ temp.meter. I've never used this type of meter but have been told and read on the site that it's very useful for the proper mixture of nutes so you don't over do it. I'm sure you all that use the Fox Farm products have saw or have the feeding chart that comes with the nutes when you buy them. It has the ppm/ec ranges and ratios along with the week of feeding. Are these ranges good for cannibus growing or should I use different ranges? I myself have no idea so I would really appreciate some knowledge from you that are growing with soil and can help me with this. And one more thing should I use RO WATER when doing the ranges or does it matter? I'm currently growing in FFOF and want have to begin applying nutrients for about 2 more weeks but when the time comes I want to have the knowledge I need to have. Thank you for your help, and have a great grow.




(GROW SPACE) Closet Grow 2ft.X 5ft.X 7ft
(LIGHTS)23 watt cfls for seedlings
600watt mh for Veg 600watt hps for Flowering
(MEDIUM) Fox Farm Happy Frog for seedlings
Fox Farm Ocean Forest for trans plant
(EXHAUST) 6inch 420 cfm inline fan through ceiling
(AIR MOVEMENT) 2-6inch clip on fans
(REFLECT) Panda Plastic
(STRAIN) NORTHERN LIGHTS FEMINIZED X 3

[Campesino]

The EC and PPM ranges are generally safe to follow - As opposed to the "recipes" which would produce EC and PPMs that are higher than advised.
PPM goes up as water evaporates from the pot so you should target the low end of the range (or below) for inflow.
In FFOF, I would start even lower and monitor that Run-off EC/PPM is not too high (above top of the range).
There are other factors to consider like Strain, Heat, RH, and watering frequency to really dial in a target inflow EC/PPM

[DoctorJohnson]

See what your water reads before you add anything and subtract that number. In other words, if your tap water is 75 PPM and target is 400 PPM, then shoot for 475.
As a rule, always start with a more dilute mixture and then slowly increase if you want. The recommended recipes, as Campesino said, tend to be more than you want. I don't know about the recommended PPM/EC values.
More feedings that are diluted are better than less feedings that are concentrated.

[Campesino]

Depends on how much you are diluting DoctorJohnson
The idea is actually to maintain a steady and healthy EC/PPM. It is entirely possible for it to be too high or too low! You are correct that variation is also problematic and your strategy of always keeping it level is correct, but I suspect you may be running significantly lower EC than needed... Although issues with recirculation may complicate that. What is your EC/PPM (and stage of growth?)
I am about to post the next installment of my Coco article that deals primarily with EC, so I have been studying this extensively!