I like 1500 PPM

Jimdamick said:

I don't know about all you wussys out there, but I LOVE high nutrient levels.
I grow my seedlings at 700 for the 1st 2 weeks, and then increase to 1000 at week 3, and then when I flip go to 1200 and at week 6 they will be at 1400 and at week 8 will be at 1500 until finish.
I grow in an RDWC with Rockwool as a starter base and then transfer to Hydroton, and have never cooked a plant, but I do get HUGE bud.

Anyone else grow at these levels, or am I just weird?

Here are my 6 week plants at 1400 PPM

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What do you run for lights and in how much space?

I think lighting can have a big impact on ppm's .I've had strains handle over 1500ppms, especially if you can get them to grow large with lots of bud sites getting direct light. Having been growing autos here lately, I've not been feeding quite as high. With those, I rarely go over 1000.

Well sure, something like plants dont grow well on only good thoughts and clean water, but grow best when given good nutrients and lights etc...

Gquebed said:

What do you run for lights and in how much space?

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One area is around 6'x6' with 1800 watts HPS for 12 plants and other area is around the same size with 5 Advanced Platinum 300 P LED fixtures for 10 plants.
All plants are in a modified Waterfarm RDWC system

I don't think you're nuts going with 1500 but only you know if it's worth it. I discovered with my grows that by going higher I didn't increase my yield any even though the plants could take it so I backed off if not just to not waste nutes. Now I like to see how low I can go and still get the same results. And I am not a super grower, like .8 gpw but it's the same at 900ppm or 1500ppm.

DaFreak said:

I don't think you're nuts going with 1500 but only you know if it's worth it. I discovered with my grows that by going higher I didn't increase my yield any even though the plants could take it so I backed off if not just to not waste nutes. Now I like to see how low I can go and still get the same results. And I am not a super grower, like .8 gpw but it's the same at 900ppm or 1500ppm.

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I just see more vigorous growth (upright leaves) at 1500.
I figured if the overall plant is doing well, I go with it.
I have grown from 700 (soil) to 1700 (hydro) and my number now is 1550 (gave up soil/waste of energy & time indoors) in a RDWC.
Good luck at 900 ppm, it didn't really work for me as well as 1500.
Here are a few plants running at 1550 for 4 weeks into bloom, and I really don't think you will see that development at 900, but who knows?

I've seen people with great results at less than 1000ppm's. I've seen people with great results as high as 1750+ ppm's. I doubt that there is an exact format from environment to environment. While, like an above poster mentioned, all factors do affect this, light intensity will have the biggest impact on the capacity to metabolize nutrients than many of the other factors. Do what works for you, no one but you knows whether or not it does.

Here is a pic of some plants grown at 900ppm. Strain is Blackberry Kush under a 1000w at 6 weeks. And I'll be honest, this is my first go with Pro-mix, after 20+ with other hydro so I am still getting used to it, experimenting, and I didn't do any training on the plants where normally I scrog, but I wanted to see what they would grow like in pro-mix so I just let them go, normally I go for a more even canopy. Also my tap is about 70ppm so that's adding to it as well. GH 3 part at 900.

Absolutely beautiful DaFreak!

DaFreak said:

Here is a pic of some plants grown at 900ppm. Strain is Blackberry Kush under a 1000w at 6 weeks. And I'll be honest, this is my first go with Pro-mix, after 20+ with other hydro so I am still getting used to it, experimenting, and I didn't do any training on the plants where normally I scrog, but I wanted to see what they would grow like in pro-mix so I just let them go, normally I go for a more even canopy. Also my tap is about 70ppm so that's adding to it as well. GH 3 part at 900.

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MINE is still bigger than YOURS!!!

(nice job / )

Like I tell my wife, it may be small but....well no, that's actually the end of it, it may be small. TY

Just a thought, what conversion factor from EC does your PPM meter use?

Say you are measuring 2000 microsiemens of EC.

Conversion at 0,5 would be 1000 PPM

Conversion at 0,7 would be 1400 PPM

If you have a meter that reads a 0,7 conversion and you want 0,5 numbers you multiply the reading by 0,714

IF your meter is reading 1500 PPM at 0,7 that would be equivalent to 1071 PPM at 0,5

Renfro said:

If you have a meter that reads a 0,7 conversion and you want 0,5 numbers you multiply the reading by 0,714

IF your meter is reading 1500 PPM at 0,7 that would be equivalent to 1071 PPM at 0,5

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Try running 1500ppm when your RH is around 25% and lower and you will fry plants. I've come to the conclusion that I need to grow in a sealed room so I can keep the environment at optimum. Just need to scrape up another grand for a decent portable AC unit and a tank of CO2 and get things dialed in properly. Need a grand to pay off last year's taxes and a couple more for this year's first tho.

Can print this out if you need a handy reference.

Renfro said:

If you have a meter that reads a 0,7 conversion and you want 0,5 numbers you multiply the reading by 0,714

IF your meter is reading 1500 PPM at 0,7 that would be equivalent to 1071 PPM at 0,5

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I'm glad you mentioned this, can't believe I forgot to ask about the conversion factor!

OldMedUser said:

Try running 1500ppm when your RH is around 25% and lower and you will fry plants. I've come to the conclusion that I need to grow in a sealed room so I can keep the environment at optimum. Just need to scrape up another grand for a decent portable AC unit and a tank of CO2 and get things dialed in properly. Need a grand to pay off last year's taxes and a couple more for this year's first tho.

Can print this out if you need a handy reference.

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Yeah humidity is most certainly a huge factor as well...if I understand it correctly, it's because the higher the RH is is the slower that the plant is able to uptake, and then transpire, nutrient water that it drinks and pushes throughout the plant? Just want to make sure I understand it right haha, good info as always OldMed

DaFreak said:

Like I tell my wife, it may be small but....well no, that's actually the end of it, it may be small. TY

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Lmfao still looks good to me!

OldMedUser said:

Just need to scrape up another grand for a decent portable AC unit and a tank of CO2 and get things dialed in properly.

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Brings back memories, more like PTSD lol. I hated hauling CO2 cylinders when I used a tank and regulator. It is so much nicer to have my CO2 generators running on natural gas plumbed into my home. I used to have to change my tank every other day with 50 pound tanks. Of course when I ran the tank it was in a 12kW room with six 4x8 tables.

Get two tanks so when one is empty you can switch immediately and refill the empty. I often see the tanks on craigslist.

Logan Burke said:

Yeah humidity is most certainly a huge factor as well...if I understand it correctly, it's because the higher the RH is is the slower that the plant is able to uptake, and then transpire, nutrient water that it drinks and pushes throughout the plant? Just want to make sure I understand it right haha, good info as always OldMed

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The VPD chart is the key there.

Logan Burke said:

Yeah humidity is most certainly a huge factor as well...if I understand it correctly, it's because the higher the RH is is the slower that the plant is able to uptake, and then transpire, nutrient water that it drinks and pushes throughout the plant?

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Exactly. You want around 60 - 75% when plants are young and vigorously growing and 50+% during early flower. It's only when the colas get big that you need lower RH to prevent bud rot so I'm good there. Winter is the worst with the RH in my grow room at 20% or lower. The plants go thru water like crazy and if the ppm is just a bit too high I get burn.

I have one of those weed sprayers that uses a 12v pump and is made to put on the back of a quad with spray arms that fold out that I'm thinking of using to get lots of water in the air. I'm thinking to hook it up to the exhaust fan controller so it turns on every time the fan does to replace the moisture lost right away. If I can get the gear I need to run a sealed room then I won't need that.

Took the words out of my mouth. PPM is really not something you can go by. PPM with VPD is what you want.

Renfro said:

Brings back memories, more like PTSD lol. I hated hauling CO2 cylinders when I used a tank and regulator. It is so much nicer to have my CO2 generators running on natural gas plumbed into my home. I used to have to change my tank every other day with 50 pound tanks. Of course when I ran the tank it was in a 12kW room with six 4x8 tables.

Get two tanks so when one is empty you can switch immediately and refill the empty. I often see the tanks on craigslist.

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I bought a 70lb tank at a yard sale but can't get it refilled. Seems you need to have an account at the refill place and rent their tanks for $100/yr then it's around $125 for refills. I doubt I'd need more than a tank a year for the size of my little grows and would only run at around 800ppm. With a sealed room it wouldn't take much to keep it at 800. I can keep it well over 800 just with my little alcohol lamp and it only uses around 50ml/day of methyl hydrate. I have a CO2 controller but have only been using it to see how the levels go up with the lamp and even just a candle. Both get over 1500 in 20 min or so. Working on the plants for half an hour with the door closed gets over 1000ppm in 15 min.

I have easy access to a gas line down there but then would need a burner and tho I'm sure I can hook it all up safely if there was a fire anywhere in the house and they found my DIY hookup my insurance would cut me off for sure. Not hiring a gas fitter to do any work down there either. Too paranoid for that.