Rockwool Cubes in Flood/Drain under LED Light

im doing purple kush in rockwool cubes on a flood/drain system under 357 magnum LED's in a sealed room. anyone doing anything like this?

just finished week 2 of bloom and they are about about 18" tall

92f daytime 84f night
1100 ppm co2
65% humidity
daily 1300 ppm feedings
no cooler, 2 small dehums running full time.


humidity is a problem right now but it doesnt seem to be effecting growth, just might see a little PM around the base of a couple of them....

anyone got any tips?

anyone have any problems with overwatering rockwool?

I dont know very much yet dude but i know my grow room was getting super hot, now that i have it regulated at 80 degrees all the time they are growing much better

Pictures please.

1300 ppm for led plants seems WAY too high, even with that heat and C02

hey kilbot
i grow in rockwool with 1000wHID but want to switch to LED. i struggle with heat and was hoping LED was the answer but your temps look pretty high.
been growing for 10yrs without a problem until 18 mths ago when i got hit with root rot - been spinning ever since. root rot is agitated by high temps, too wet and no oxygen. i tried everything, (too much to list) but eventually i had to ignore everything i had learned over the years re feeding and let the plant set the feedings. i finally got through 2 rooms this winter - roots brown but actually still produced a 3/4 oz/plant not bad for sick plants.
i recommend you let the rockwell almost dry right out before feeding again.
as for ppm maybe a little high but your plants will tell you - yellow around the tips and they will stop growing.
you are in a really strong grow period right now, if you can't see that your plants have grown every couple of days there is likely a problem.

was wondering how big your room and table are?
did you grow with hid before led?
does your led have builtin fans?

good luck with your grow

Hey sandy,
This is my first show on my own but have been around friends and their rooms for years now... They all still used hid.
The roots poking out the bottom are browning but I don't seems to be suffering any nute lockout or anything. It's day 15 of flower and I'm getting buds popping up all over the place... I'm letting the top half of my medium dry out before watering. I'm also alternating weeks of live enzymes in the reservoir. From what I can tell there is no sign of PM or algae so I'm not too worried about it.

How often do you flood your tables? How long does the drain take? And do you have high humidity?

Also yes the LED panels have 6 built in fans ... 80% of my heat is coming from the 6 burner co2 gen and the de hums though

@ ninja

Why would an LED grow use less nutes?

I have a sealed tent magnum grow right now. Just getting it all dialed in.

Rian said:

I have a sealed tent magnum grow right now. Just getting it all dialed in.

Click to expand...

thats cool i think im going to get a smaller 9000 btu air conditioner and vent it out of the chimney in my grow room. this will create a little negative air flow and seep a bit more co2 out of the room but i think bringing the temp down and humidity will make it worth it

post some pics homie, been curious how leds look irl.. the pics in the magazines always look like something from an hid moved under and led for photo purposes. however if your doing well with it id love to see.

Hey Kilbot
How often - I start in flowering with with 1 feed a day and increase it 1 a week on average but I always spot check to make sure they are getting what they need. I let mine dry out more than 1/2 in between, but that is because I am terrified of root rot.
How long - that depends on the speed of the pump. I time the first feed to see how long it takes to flood my lowest cube up about an inch - Mine is about 8 - 10 mins.
My room is very hot and humid. I try to keep the resevoir between 68 and 70 but thats a struggle.
Brown roots - see if they are strong roots. They shouldn't be mushy, you should be able to drag your nail across them with out them breaking apart. Compare the brown roots to the white ones, they should be the same only a different colour. Some nutes and additives turn the roots brown so it is not always a bad sign.
How big is your table? How many plants to you grow under the 357? I am not familiar with all the different strains, etc, about how long do you plan to flower? How tall will they get?
I am thinking about buying the 357 this week but am not sure what size of grow area it will cover and if it will be enough to penetrate through my plant canopy.
hope you don't mind all the questions - I know you were here looking for answers.

Hey sandy.. The 357 uses 60 degree lenses on the red part of the spectrum which penetrates quite well but has a pretty small foot print... For a 4x8 table with 75 or so 18" - 2 footers you would need 3 per table. The overlapping of the coverage areas is great for the PAR levels too. FYI I went and got a better digi thermometer and It shows my humidity at 59% which ain't bad? Prolly will not cause PM?

is it heat score to post pics on here?

Kilbot said:

is it heat score to post pics on here?

Click to expand...

lol its not heat score just dont show your face or anything stupid lol
hey fellow british columbian! you whatching the playoffs or what????
goodluck and im subbed, i'll be peeking in on this periodically !
peace

mijola3 said:

lol its not heat score just dont show your face or anything stupid lol
hey fellow british columbian! you whatching the playoffs or what????
goodluck and im subbed, i'll be peeking in on this periodically !
peace

Click to expand...

woot go nucks go!

just added more lights to the room which is raising the heat up again
they at 93f =( the extra light is nessesary though so ill have to get an AC

was using 357 magnums over 4x8 flood tables ...spread them apart a bit and put a 500 watt blackstar inbetween them....PAR levels increased a ton even though the blackstars use different bands...dont know if that will be bad or good.

so it looks like this:

****[357 mag]****[500 blackstar]****[357 mag]****

|_________________4x8 table____________________|

will update pics soon