Cold floor causing nitrogen deficiency?

Freda Felcher

Freda Felcher

Well-Known Member
So I have been battling yellowing leaves on my AK-47 plants for over a month. I'm doing a small perpetual grow, or attempting to. Every time my plants go into flowering they start yellowing early on and it slowly moves up the plant. For a while i thought they were lacking magnesium, or had a severe pH imbalance. Yesterday, after noticing more yellowing, i sat down and looked at my plants for a good twenty minutes. I noticed two of them were still very green and lush, with little to no yellowing. After some more examination I noticed the two healthy plants had one big difference. They were a few inches shorter than the other plants when I put them into flower so I have them set on 2x6's. I'm pretty sure the 2x6's are insulating the flower pots from the cold cement floor. So what i think is the roots are too cold and is slowing the plants ability to take in nitrogen. I read about this somewhere. Does anyone have any thoughts on this?
 
Freda Felcher

Freda Felcher

Well-Known Member
I also put a thermometer on the floor just see what it would read. It was at 55 F last I checked. That is with the 600w hps light on. That has to be entirely too cold for the soil temps. I found an article in the plant problems FAQ that talked breifly about nitrogen lockout from cold soil temps. Hopefully this is the cause of all the yellowing and dead leaves. Now to come up with a way to insulate between the pots and the cement floor?
 
lifted02350

lifted02350

Member
no thoughts but i might have the same problem now that u mention it and its like3 degrees out cant be good
if u find out more post it up
 
lifted02350

lifted02350

Member
build a raised floor out of 2x4 and insulate it then cover it with plywood then mabye some sticky tiles just for water overflow the plywood would warp
 
Freda Felcher

Freda Felcher

Well-Known Member
lifted02350 said:
no thoughts but i might have the same problem now that u mention it and its like3 degrees out cant be good
if u find out more post it up
Click to expand...
Will do! It's not really somthing you read about a whole lot, but if you look hard enough, it's in some of the plant problem faq's. Hopefully in the meantime someone else may have some experience in this subject to add.
 
cph

cph

Well-Known Member
Nice to see you answered your own question!:clap:

You really only need to get them off the ground. Even f it's only 1 inch. Allowing air to get under it will make all the difference. I think I'm having the same problem even with my plants about 12" off the ground. But my room gets down into the mid 50s at night, doesn't help when it's fcken 5 degrees outside!!:wall:

Good luck!!!
 
CLOSETGROWTH

CLOSETGROWTH

Well-Known Member
Freda Felcher said:
So I have been battling yellowing leaves on my AK-47 plants for over a month. I'm doing a small perpetual grow, or attempting to. Every time my plants go into flowering they start yellowing early on and it slowly moves up the plant. For a while i thought they were lacking magnesium, or had a severe pH imbalance. Yesterday, after noticing more yellowing, i sat down and looked at my plants for a good twenty minutes. I noticed two of them were still very green and lush, with little to no yellowing. After some more examination I noticed the two healthy plants had one big difference. They were a few inches shorter than the other plants when I put them into flower so I have them set on 2x6's. I'm pretty sure the 2x6's are insulating the flower pots from the cold cement floor. So what i think is the roots are too cold and is slowing the plants ability to take in nitrogen. I read about this somewhere. Does anyone have any thoughts on this?
Click to expand...
Good diagnosis Professor :)
 
Freda Felcher

Freda Felcher

Well-Known Member
cph said:
Nice to see you answered your own question!:clap:

You really only need to get them off the ground. Even f it's only 1 inch. Allowing air to get under it will make all the difference. I think I'm having the same problem even with my plants about 12" off the ground. But my room gets down into the mid 50s at night, doesn't help when it's fcken 5 degrees outside!!:wall:

Good luck!!!
Click to expand...
My room has been dipping down into the low 60's. Today it's about 7 degrees outside, so I would imagine it may be in the 50's in my room as well.
 
cowboylogic

cowboylogic

Well-Known Member
First off nice job on solving your own problem and sharing the info. Second, I have a raised floor in my grow space. But instead of plywood I use pegboard. Gets your pots up to keep them warm in the winter. You can put a sheet of foam board over it if needed in the winter. Then in the summer it allows for a cool air intake. A few well placed vents at the top and you get a nice natural convection to keep things cool.
 
Freda Felcher

Freda Felcher

Well-Known Member
cowboylogic said:
First off nice job on solving your own problem and sharing the info. Second, I have a raised floor in my grow space. But instead of plywood I use pegboard. Gets your pots up to keep them warm in the winter. You can put a sheet of foam board over it if needed in the winter. Then in the summer it allows for a cool air intake. A few well placed vents at the top and you get a nice natural convection to keep things cool.
Click to expand...
I like your idea with the peg board and holes and may incorporate it when I expand out of this 3x3 tent. For now, I have all of the plants propped up on 2x6,s and rubbermaids. I plan to put at least 4-6 inches of insulation foam board down underneath the tent. That should eliminate the cold soil problem I Hope! Here is a pic I took of my tent earlier this evening....
 

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Freda Felcher

Freda Felcher

Well-Known Member
cph said:
Nice to see you answered your own question!:clap:

You really only need to get them off the ground. Even f it's only 1 inch. Allowing air to get under it will make all the difference. I think I'm having the same problem even with my plants about 12" off the ground. But my room gets down into the mid 50s at night, doesn't help when it's fcken 5 degrees outside!!:wall:

Good luck!!!
Click to expand...
LOL! I know, I did answer my own question kinda, but was more looking for suggestions on insulating the floor. I also hope this helps someone who is in my position. I dealt with this now for close to two months and at times, was ready to bag it. So if nothing more, if this thread helps someone else, it's a complete success in my book!
 
mrdrywall

mrdrywall

Active Member
i had my plants on cement alsoroom stays about 75 but floor was very coldhad yellow leaves also thought it was nutes at first raised them up 6 incheswith plywood sitting on empty pots seems to have helped a lot stuck my finger into soil and big differance in the temp now and no yellow leaves also buds are larger and still growing month left
 
Freda Felcher

Freda Felcher

Well-Known Member
mrdrywall said:
i had my plants on cement alsoroom stays about 75 but floor was very cold had yellow leaves also thought it was nutes at first raised them up 6 inches with plywood sitting on empty pots seems to have helped a lot stuck my finger into soil and big difference in the temp now and no yellow leaves also buds are larger and still growing month left
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Thanks for adding your experience with this problem mrdrywall. How long ago did you raise them off the floor and did the color come back noticeably right away?
 
Freda Felcher

Freda Felcher

Well-Known Member
mrdrywall said:
i cut yellow ones off and then raised em none came back
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I have trimmed some of the big fan leaves towards the bottom that looked too far gone. But there was also a lot of newer growth toward the top that is yellowing some. I am hoping the younger leaves will return to normal.
 
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