Addie42069
New Member
Hemp/CBD bagseed
5 gal DWC
Age: 58 days, week 2 flower
Light schedule: 18/6 (apparently she's an auto)
DLI: 25
VPD: 1.3
I first tested this 2 days ago based on my most recent ppm measurement (day prior) and was expecting a ppm reading of 1250, it read 1150. That's only an 8% difference so I figured fuck it that's close enough to look further into it.
3 gal = 588 ppm (fresh res)
2 days later
1.5 gal = 769 ppm
"Ate" = 386 ppm
Desired PPM = 535
To get the 1.5 gal in the res from 769 to 535 the 1.5 gal top off solution should be 301. To dose the 1.5 gal with 301 of nutes I cut the dosage down to 25% strength of what I mixed to get my starting res of 588.
After Mixing the top off solution the ppm was 332. Mixing 1.5 gal of 332 to 1.5 gal of 769 should be 550. It measured 566, close enough.
So in theory she will drink the same 386 plus, I'm guessing, a little extra as she gets older. If this holds true we can calculate, within a reasonable degree of accuracy, how much water vs nutrients each individual plant is taking up and adjust accordingly.
Even though I calculated that she ate 386 ppm, I didn't want to drop the ppm that low because she doesn't seem to mind it where she is.
Once I get a baseline of how much she's eating I plan to start adjusting variables to see what happens. My first move is to increase the DLI to see how it effects nutrient uptake. From what I've read, higher DLI should mean more nutrient uptake but I'd like to actually put a number to it. I'm going to increase DLI by 5 on a weekly basis on the same day as the res change. Once she starts to show signs of stress I will back off a little and leave the DLI alone.
Next I plan to adjust VPD to see how it effects the nutrient uptake, then I'll consider adding CO2. This obviously won't all be done with this same plant. The initial testing will be done one her but they next seed I plant is going to be a feminized CBD photo. Ideally I will keep her in veg long enough to test everything mentioned above. The goal is to put together a calculator where you can input your environment parameters and get an accurate reading of your plant's needs. No more guessing!
Any input is greatly appreciated. Is there something I'm not considering? Has anyone tried something like this before? I spent multiple evenings trying to get some information on this but I got nothing.
TLDR: The goal is to put together a calculator where you can input your environment parameters and get an accurate reading of your plant's nutrient needs. No more guessing!
5 gal DWC
Age: 58 days, week 2 flower
Light schedule: 18/6 (apparently she's an auto)
DLI: 25
VPD: 1.3
I first tested this 2 days ago based on my most recent ppm measurement (day prior) and was expecting a ppm reading of 1250, it read 1150. That's only an 8% difference so I figured fuck it that's close enough to look further into it.
3 gal = 588 ppm (fresh res)
2 days later
1.5 gal = 769 ppm
"Ate" = 386 ppm
Desired PPM = 535
To get the 1.5 gal in the res from 769 to 535 the 1.5 gal top off solution should be 301. To dose the 1.5 gal with 301 of nutes I cut the dosage down to 25% strength of what I mixed to get my starting res of 588.
After Mixing the top off solution the ppm was 332. Mixing 1.5 gal of 332 to 1.5 gal of 769 should be 550. It measured 566, close enough.
So in theory she will drink the same 386 plus, I'm guessing, a little extra as she gets older. If this holds true we can calculate, within a reasonable degree of accuracy, how much water vs nutrients each individual plant is taking up and adjust accordingly.
Even though I calculated that she ate 386 ppm, I didn't want to drop the ppm that low because she doesn't seem to mind it where she is.
Once I get a baseline of how much she's eating I plan to start adjusting variables to see what happens. My first move is to increase the DLI to see how it effects nutrient uptake. From what I've read, higher DLI should mean more nutrient uptake but I'd like to actually put a number to it. I'm going to increase DLI by 5 on a weekly basis on the same day as the res change. Once she starts to show signs of stress I will back off a little and leave the DLI alone.
Next I plan to adjust VPD to see how it effects the nutrient uptake, then I'll consider adding CO2. This obviously won't all be done with this same plant. The initial testing will be done one her but they next seed I plant is going to be a feminized CBD photo. Ideally I will keep her in veg long enough to test everything mentioned above. The goal is to put together a calculator where you can input your environment parameters and get an accurate reading of your plant's needs. No more guessing!
Any input is greatly appreciated. Is there something I'm not considering? Has anyone tried something like this before? I spent multiple evenings trying to get some information on this but I got nothing.
TLDR: The goal is to put together a calculator where you can input your environment parameters and get an accurate reading of your plant's nutrient needs. No more guessing!
