1500W LED DIY (Flood and Drain)(problemoz wif plantz)(need tips)(pics)

arcalion

Well-Known Member
Too low, should be around 60% at 84°F! Below is a chart about VPD at different temps. It already factors in 2° lower leaf temperatures against ambient, as usual with LEDs. You can use it like it is!
If the vapor pressure difference inside the leafes is too high your plants transpire much more water, more water uptake means also more nutrient uptake, especially calcium and too much Ca blocks other elements like Magnesium, Iron and others. The results can look like a Mg deficit but you also see other signs of nutrient stress like purple veins, chlorosis and so on.
To avoid issues you can either use less nutes(25% too high VPD = 25% less nutrient strength) or you increase you humidity according to the list below.
I would use an IR thermometer to messure the leaf temps. Messsuring at ~20cm distance to the canopy should give you almost correct values you can work with. Usually the leaf temps are 2-4° lower than ambient temps with LED (blurple a bit more, with whites a bit less).

View attachment 4160473
both my rooms are around the same humidity ive never had a problem in that room it being 45-60% nights my flower temps are around 23C-25C
 

arcalion

Well-Known Member
PS forgot to mention the LED on the one side is like 800Watts and its pretty far from the light, I came from a 600Watt light from the veg room, so that wouldn't be a problem...
 

Randomblame

Well-Known Member
both my rooms are around the same humidity ive never had a problem in that room it being 45-60% nights my flower temps are around 23C-25C

Night temps doesn't matter so much when it comes to VPD. The humidity below the fixture could be much lower with lights on. My humidity sensor hangs directly between the tops because there was a 10% difference to the values I get when mounted on the wall. Every time my plants looks droopy it has something to do with the enviromental conditions. As soon as all is within a certain range again they perk up again. There are a few differences to HPS growing.
 

arcalion

Well-Known Member
ok so i just gave the res some Grow nutes and raised it to 1.4Ecs added 40ml of Clorox, they were droopy asf when the lights came on definitely not taking in any food. maybe going from Grow nutes straight to Bloom nutes was Bad news bears.
 

arcalion

Well-Known Member
Bad news bears they've not even perked up or anything as if they drank the nutrient. They just look absolutely sadder today. I dont get why I'm so stumped in this room.
 

arcalion

Well-Known Member
At this point I feel like I should have just continued using grow nutes 1-2weeks into flower before even switching over. Might have been a mistake to just give straight bloom
 

growingforfun

Well-Known Member
At this point I feel like I should have just continued using grow nutes 1-2weeks into flower before even switching over. Might have been a mistake to just give straight bloom
Imo it's best to start giving bloom nutes a week before flower and also continue giving veg nutes a week or 2 into bloom. Helps flower set faster ime.
 
ok so i currently i have changed over to a flood and drain, i use rockwool 6inch cubes for the majority of my grow, i do 45 days from seed then transfer, the plants are wonderful but by the time i put them into flower and transfer within 2 days they go from praying to the sun gods to being droopy af and turning purple, i try to exchange the nutrients in the res, im currently at .8 ECs while changed to Flower nutrient regime but there still perking down and im getting rotted roots. i've cleaned the res i have it under 70F i've got a little bit of root excelurator in there and some Drip clean to help keep it sanitary. so far this has happened twice putting my plants into the flowering room. even with my soil grows they would do the exact same thing. i just dont understand, i just added AC unit so i no longer have heat problemoz.. any suggestion fixing this problem? What would you do? i also added a little bit of Cal-Mag to see if it would bounce from that, while remaining under 1.0 EC's
why is it so difficult for me to tell if its a toxicity or a deficiency
The water needs to be more oxygenated and an old timer told me water temperatures affect oxygen levels
 

Rocket Soul

Well-Known Member
What's your humidity inside the room? Could be too low! It's a common issue with LED and temps around 80-84°F.

And how much light did you have per sft? High intensity levels(above 800μmol/s/m²) cause higher nutrient demands and especially under low humidity it's difficult to keep them healthy/happy.

I would dimm the light by 25% or hung it higher and I would try to keep my humidity around 60%. If they perk up again I would increase the brightness again but slowly.
Your plants look hungry and droopy. Im Iith Random, i i think your plants arent transpiring properly, no transpiration then they dont uptake any water, no drinking then no nutes uptake, nomatter what you put your EC at. Get your environment right, check the VPD sheet he posted and make sure your cannopy enviroment is in line. Generally it would mean temps around 25C and rh 60-70 ish if your spectrum is low on IR.
 

Randomblame

Well-Known Member
With H2O2 one could add some oxygen and keep the res clean.
I would rather have 65°C res temps to avoid issues with pathogenes. Maybe you need to run the res from outside of the tent. With up to 85°F inside the tent it's impossible to keep the reservoir temps around 65°F unless you use an additional chiller.
That's another issue with LED and high ambient temps..

The plants in the first two pictures look like they did not get enough nitrogen and phosphorus in the growth stage. The stems and leaf stems too have purple discolorations almost everywhere, the leaves are only bright green, and the lower leaves die too early in the flower stage. Most of them can not happen in only two days...
In the growth tent increase the nutrient concentration by 25% and regularly add 5ml CalMag per gal. from the 2nd veg week. It's important that enough of this elements are already available while the plants are growing(these elements are immobile). You need less CalMag when they stop stretching.
 
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arcalion

Well-Known Member
guys my res is always 65-68 in my flower room,
im going with the the people who've said that you still need grow nutes in flower for first couple weeks,
1-2weeks before putting my plants into flower they were getting purple stems, i believe it might have happened because i was underfeeding them i was at 0.6 - 0.8 ECs at the time. so what i did was exchange all the res water with new Nutes so that i had a balance of nutes again because i might have been getting more deficient in some of the macro nutrients. they perked right up after i did that. it somewhat reversed the purple stems and starting growing better
i did one final feed in my veg room and brought them into the flower room and they looked fine and great, once two days came along i just gave them straight BLOOM food with the same ECs with no Grow food, which was working at the time
i feel like my plants might have been confused with the drastic change in nutes
 

nfhiggs

Well-Known Member
guys my res is always 65-68 in my flower room,
im going with the the people who've said that you still need grow nutes in flower for first couple weeks,
1-2weeks before putting my plants into flower they were getting purple stems, i believe it might have happened because i was underfeeding them i was at 0.6 - 0.8 ECs at the time. so what i did was exchange all the res water with new Nutes so that i had a balance of nutes again because i might have been getting more deficient in some of the macro nutrients. they perked right up after i did that. it somewhat reversed the purple stems and starting growing better
i did one final feed in my veg room and brought them into the flower room and they looked fine and great, once two days came along i just gave them straight BLOOM food with the same ECs with no Grow food, which was working at the time
i feel like my plants might have been confused with the drastic change in nutes
I just use Bloom nutes from start to finish now. With Grow nutes I kept seeing N-tox every few weeks.
 

nfhiggs

Well-Known Member
whats the breakdown of your bloom nutes?
I was using GH Maxibloom which is 5-15-14. Way less N than most grow nutes but I have not had any issues with N deficiency in Veg - fact, it stopped my periodic N-tox I kept seeing with the GH MaxiGro.

With the plants I just started I'm using MegaCrop. I'm not sure what the numbers are on it.
 

arcalion

Well-Known Member
Ok so my plants are all bouncing back atm, last night i decided to change out the Res and just put grow nutes, i hand watered all of them to drain out the Bloom nutes. probably just need to increase the e.c's to 1.0-1.2 atm in the coming week
 

JohnDee

Well-Known Member
So the people who said they look like theyre starving for nitrogen are right!
And don't forget the flood timing thing. You were allowing the cubes to dry a bit which from everything I've read is bad.

In Holland the grow greenhouses full of commercial crops on rockwool...but always top drip.

I have done E&F with hydroton feeding x5 daily with excellent and healthy results. I know...different media.

I'd use that tray with cubes and plumb it for top drip.
JD
 

banke1

Well-Known Member
ive had serious issues with bringing my ladies from veg to bloom (separate rooms)… like full plant droop, purple stems, and hermies. now I am OCD about putting multiple temperature and humidity gauges in each room and matching them. I keep both veg and bloom room ACs set to 70 but because of the differences in the rooms (different ac's, different insulation, wattage load, airflow etc) my veg room is really about 80-85* near canopy and my bloom room is 70-73* near canopy. so now I just set my bloom AC to 77 and it keeps the room 77-80. then every other day I lower it one degree until its set to 70*

edit: im pretty sure I was damaging the root zone because my problems included a plethora of different symptoms (full leaf droop, stiff purple stems, yellowing, patches of brown spots, dying leaves, and eventually hermies) and they were praying and beautiful 100% health before the switch.

also I put my gavitas at 600w and work them up every couple of days as well
 
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