PPM Question

BigEasy1

BigEasy1

Well-Known Member
I'm new to this and don't quite understand the PPM. The Fox Farms feeding schedule for hydro says I should be between 1260-1400 at week three of veg. I was following the feeding schedule but was having problems with the leaves spotting, turning brown then drying up. I changed the water and backed off the nutes and am now between 500-600 PPM as someone suggested. It's only been a few days but the plants seem to be doing better. Why does the feeding schedule recommend that I should be at almost double of what seems to be working better? The jury is still out so I don't know for sure but it looks like the new growth is healthier. Any replies are appreciated.
 
hotrodharley

hotrodharley

Well-Known Member
Dude I have NEVER had a plant do well if PPM exceeds 700 and I use AN exclusively. At 3 weeks my PPM is more like 250-300 in DWC. Back off to a level nearer that and see if the plant does not respond quickly.
 
BigEasy1

BigEasy1

Well-Known Member
Yeah, I'm starting to understand that now after I jacked my plant up! Lol I don't understand though the feeding schedule and why it calls for such a high PPM. I think I'm at about 550 PPM right now but maybe I should even dilute that down a little with some fresh PH'd water?
 
T

thinn

Well-Known Member
I dont think the ppm schedules were geared toward one plant, specifically cannabis. You will always have to figure out what works for the particular plant you are growing, maybe if you were growing a fruit bearing plant like tomatoes it would need all of that energy. Weeds are leeches so they thrive everywhere
 
BigEasy1

BigEasy1

Well-Known Member
Ok, yeah that makes sense but I kind of thought the Fox Farms stuff and similar nutrients were geared towards weed. After I backed my nutes down I have noticed my PH rises during the day while I'm at work. When I leave I usually get it to around 5.8 and by the time I get home it's up to around 6.0 or 6.1. Does this mean the plant is consuming the nutrients?
 
T

thinn

Well-Known Member
How quick are you checking your ph? Ph your water and let it sit for a half hour to an hour before you check, if you check too quick you could be just getting a phantom reading/incorrect reading.
 
hotrodharley

hotrodharley

Well-Known Member
BigEasy1 said:
Ok, yeah that makes sense but I kind of thought the Fox Farms stuff and similar nutrients were geared towards weed. After I backed my nutes down I have noticed my PH rises during the day while I'm at work. When I leave I usually get it to around 5.8 and by the time I get home it's up to around 6.0 or 6.1. Does this mean the plant is consuming the nutrients?
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Look up RIU poster Superstoner. That cat can get you on the road to hydro happiness in short order. Then check the hydro forums here. I'm far from being an expert and learned the PPM thing the hard way. Pain - the teacher whose lessons are in memory much longer.
 
Krondizzel

Krondizzel

New Member
hotrodharley said:
Look up RIU poster Superstoner. That cat can get you on the road to hydro happiness in short order. Then check the hydro forums here. I'm far from being an expert and learned the PPM thing the hard way. Pain - the teacher whose lessons are in memory much longer.
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I've got the hydro thing down pat. If you need help with your hydro lemme know.
 
Krondizzel

Krondizzel

New Member
BigEasy1 said:
I'm new to this and don't quite understand the PPM. The Fox Farms feeding schedule for hydro says I should be between 1260-1400 at week three of veg. I was following the feeding schedule but was having problems with the leaves spotting, turning brown then drying up. I changed the water and backed off the nutes and am now between 500-600 PPM as someone suggested. It's only been a few days but the plants seem to be doing better. Why does the feeding schedule recommend that I should be at almost double of what seems to be working better? The jury is still out so I don't know for sure but it looks like the new growth is healthier. Any replies are appreciated.
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All strains are different. My advice is to start out low and work your way up. Fixing nutrient burn is far more difficult than fixing a nutrient deficiency
 
Krondizzel

Krondizzel

New Member
thinn said:
How quick are you checking your ph? Ph your water and let it sit for a half hour to an hour before you check, if you check too quick you could be just getting a phantom reading/incorrect reading.
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Sometimes the PH will change on you yes, that is why you always check check check and recheck your PH.
 
Pipe Dream

Pipe Dream

Well-Known Member
Krondizzel said:
No..... PPM is measuring the parts per million of total dissolved solids buddy. PPM is PPM. The higher the number, the more crap that's in the water.
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how big are the parts?

I can't go to the grow guide where it was posted because the site's down. EC (Electrical Conductivity?) is supposed to be a much more accurate way to measure dissolved solids.
 
Pipe Dream

Pipe Dream

Well-Known Member
I know common sense says that's true, but the PPM meters take a EC reading I think and then convert the reading into PPM using an equation and they don't all use the same equation.
 
Krondizzel

Krondizzel

New Member
Pipe Dream said:
I know common sense says that's true, but the PPM meters take a EC reading I think and then convert the reading into PPM using an equation and they don't all use the same equation.
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I think I'll leave it up to the manufacturer to worry about stuff like that to be honest. I see what you are saying though!
 
Pipe Dream

Pipe Dream

Well-Known Member
Krondizzel said:
I think I'll leave it up to the manufacturer to worry about stuff like that to be honest. I see what you are saying though!
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I think there is 2 different PPM readings. It's like metric vs american measurements. It's not just a small difference in PPMs it's like 1.5 x different I think so it could cause huge problems if your using a different kind of meter as someone saying to run a specific PPMs.
 
WattSaver

WattSaver

Well-Known Member
ppm is ppm

ppm is derived from a factor of the ec reading, .5 or.7 are the standards

Now here is the kicker ec is temp sensitive. ie the same sample will read different at different temps. My meter temp corrects it's readings. but hey it's a $200 meter.
 
hotrodharley

hotrodharley

Well-Known Member
EC is much more precise than PPM. In dialysis we use strictly "Conductivity" as our measurements every 4 hours when we test our water. EC is used in Europe, where metrics rule, while we are stuck with SAE frigging hardware/tools and PPM.

However, once one measures and uses PPM as their guide the results are basically the same. For DWC or RDWC especially PPM is fine.
 
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