Potassium deficiency?
- Thread starter astra
- Start date
Scientific
New Member
It really helps to see the leaf in situ on the plant (like is it a top leaf or a bottom leaf or?).
The first two photos seem to show a little scalloping of the leaf edges that is usually a sign of excessive hear and/or light (though early wind burn from too much fan circulation can sometimes give something like that too).
The leaf tips look like they might have gotten nute burn a while back. Were they originally kind of yellow at the tips? Again, could maybe be damage from too much light on a top leaf, but my guess would be nute burn, especially since you say you're feeding "as directed on the bottle" and manufacturer's recommended levels are too high so often that the general advice is to feed at 1/2 the recommended level until you are sure the plants can take more.
Again, shots of the leaves on the plant would help, and if you answer the Qs at the "How to Ask for Grow Support" sticky, that helps even more.
Good luck and have fun.
The first two photos seem to show a little scalloping of the leaf edges that is usually a sign of excessive hear and/or light (though early wind burn from too much fan circulation can sometimes give something like that too).
The leaf tips look like they might have gotten nute burn a while back. Were they originally kind of yellow at the tips? Again, could maybe be damage from too much light on a top leaf, but my guess would be nute burn, especially since you say you're feeding "as directed on the bottle" and manufacturer's recommended levels are too high so often that the general advice is to feed at 1/2 the recommended level until you are sure the plants can take more.
Again, shots of the leaves on the plant would help, and if you answer the Qs at the "How to Ask for Grow Support" sticky, that helps even more.
Good luck and have fun.
- Thread starter
- #3
Thanks for your reply, really appreciate it.
Strain - cheese
# of Plants - 8
Grow Type - Coco
Grow Stage - 5th-6th week
Bucket Size - 20 ltr
Lights - (2) 600 Watt HPS
Nutrients - ionic bloom, Buddha's tree PK 9-18 and meta boost
Medium - Coco
EC - 1.6
PH - 5.8 - 6.0
RH - 40% to 50%
Room Temperature -21 to 24
Room Square Footage - 2.4 X 1.2 tent
Pests - None Known
The strength of the nute mix was the same as the previous week, all seemed ok then and i
didn't notice any yellowing. I have only followed the guidance of manufacture on the PK9-18, I use a EC pen to measure nutes.
I have moved the lights a little higher but again they have been alright up until this point. The effected area is on the top third of the plant. Here are a few photos. Thanks again.
Strain - cheese
# of Plants - 8
Grow Type - Coco
Grow Stage - 5th-6th week
Bucket Size - 20 ltr
Lights - (2) 600 Watt HPS
Nutrients - ionic bloom, Buddha's tree PK 9-18 and meta boost
Medium - Coco
EC - 1.6
PH - 5.8 - 6.0
RH - 40% to 50%
Room Temperature -21 to 24
Room Square Footage - 2.4 X 1.2 tent
Pests - None Known
The strength of the nute mix was the same as the previous week, all seemed ok then and i
I have moved the lights a little higher but again they have been alright up until this point. The effected area is on the top third of the plant. Here are a few photos. Thanks again.
Scientific
New Member
Those plants look good!
The scalloped edges and turned-up tips look like heat/light/low humidity stress to me. Moving the light up should help.
Photos taken with white light are much preferred when trying to evaluate leaves since color is important...
The scalloped edges and turned-up tips look like heat/light/low humidity stress to me. Moving the light up should help.
Photos taken with white light are much preferred when trying to evaluate leaves since color is important...
- Thread starter
- #5
I've raised the light as you suggested as it seems closer than those of others on 420.
As you mention it, it could be low humidity as I've been struggling to keep it above 40%. Not sure how I can overcome this as I an exhaust to draw fresh air through. So it seems it could be a combination of both light stress and low humidity.
Thanks, appreciate your help.
As you mention it, it could be low humidity as I've been struggling to keep it above 40%. Not sure how I can overcome this as I an exhaust to draw fresh air through. So it seems it could be a combination of both light stress and low humidity.
Thanks, appreciate your help.
Scientific
New Member
Yeah, you can get a quadruple whammy with light+heat+low humidity+too much wind. Any and all can stress the plant.
A big baking pan full of water directly in the path of the fan (i.e. fan blowing on it) can help. Wet surface area is the name of the game, so sponges placed in the pan, paper towels draped in it, etc all can help a lot. (They also can provide significant evaporative cooling in a dry environment.)
A big baking pan full of water directly in the path of the fan (i.e. fan blowing on it) can help. Wet surface area is the name of the game, so sponges placed in the pan, paper towels draped in it, etc all can help a lot. (They also can provide significant evaporative cooling in a dry environment.)
- Thread starter
- #7
Scientific
New Member
I'd suggest trying the pan first and see how that works. Make sure the fan is blowing right on it. Add some surface area with sponges or draped paper towels.
You can buy a little aquarium water pump at the pet store that will pump water to the top of the paper towels or you can even by a replacement element for an evaporative cooler and run the water up to the top of that. I did that and it was cheap and effective and lowered the temperature and raised the humidity. (Or you can just buy a little evaporative cooler.)
Here's my home made rig. The reservoir at the bottom should have been bigger because it dried out fast, but it worked great (fan behind the element, tiny pump in the tray).
You can buy a little aquarium water pump at the pet store that will pump water to the top of the paper towels or you can even by a replacement element for an evaporative cooler and run the water up to the top of that. I did that and it was cheap and effective and lowered the temperature and raised the humidity. (Or you can just buy a little evaporative cooler.)
Here's my home made rig. The reservoir at the bottom should have been bigger because it dried out fast, but it worked great (fan behind the element, tiny pump in the tray).
- Thread starter
- #9
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