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Edema Issues

Alright gang, I'm calling in the brain trust on this one. 
 
I'm having some edema problems with my Carolina Reaper and Trinidad Scorpion plants that I'm overwintering. the Ghost in the same room appears to be unaffected. 
 
Symptoms: Edema on both leaf surfaces on the Reaper's new growth. (upper and lower) Edema only on lower surfaces of Scorpion. Ghost unaffected.
 
Reaper:
Reaper Edema.jpeg

 
Scorpion:
Scorpion Edema.jpeg

 
What I've tried so far:
 
  • Less Water:  Allowing soil to dry pretty thoroughly before watering. Withholding water up to a week shows no effect. 
  • Air Movement: Oscillating fan added, runs on the same timer as the lights. No noticeable effect. 
  • Temp/Humidity: Monitoring this, but not actively controlling it. Humidity stays around 60-70% in the room. Temperature swings between low 60s and mid 70's when the lights are running.
 
What variable is behind the edema? the only thing I can think to change is running the fan at night and lowering the humidity. Anyone else had an issue like this with an indoor grow?
 

CaneDog

Extreme Member
Can be a hard thing to correct and seems to affect certain types and individual plants more than others. Isolating a variable isn't easy or necessarily possible.  Adequate plant spacing indoors may factor in.
 
Here are some good resources on Intumescence and Edema.
 
Edema vs. Intumescence
https://ag.umass.edu/greenhouse-floriculture/fact-sheets/edema-intumescence
 
Info on Intumescences
http://gpnmag.com/article/intumescences-physiological-disorder-greenhouse-grown-crops/
 
More detailed info on Intumescences
http://gpnmag.com/wp-content/uploads/08_Intumescences_GPN0914.pdf
 

PaulG

Extreme Member
CaneDog said:
Can be a hard thing to correct and seems to affect certain types and individual plants more than others. Isolating a variable isn't easy or necessarily possible.  Adequate plant spacing indoors may factor in.
 
Here are some good resources on Intumescence and Edema.
 
Edema vs. Intumescence
https://ag.umass.edu/greenhouse-floriculture/fact-sheets/edema-intumescence
 
Info on Intumescences
http://gpnmag.com/article/intumescences-physiological-disorder-greenhouse-grown-crops/
 
More detailed info on Intumescences
http://gpnmag.com/wp-content/uploads/08_Intumescences_GPN0914.pdf
Great info CD.

I have found that edema is pretty intractable in my garage in
early months of growing. Once plants go outside, the issues
seem to resolve themselves, as the articles above state.

Since you are fanning and monitoring water and light, there
isn’t a lot else you can do. In my own grows it seems to be
a nuisance more than anything else.

Good luck going forward, DM.
 
PaulG said:
Great info CD.

I have found that edema is pretty intractable in my garage in
early months of growing. Once plants go outside, the issues
seem to resolve themselves, as the articles above state.

Since you are fanning and monitoring water and light, there
isn’t a lot else you can do. In my own grows it seems to be
a nuisance more than anything else.

Good luck going forward, DM.
 
 
CaneDog said:
Can be a hard thing to correct and seems to affect certain types and individual plants more than others. Isolating a variable isn't easy or necessarily possible.  Adequate plant spacing indoors may factor in.
 
Here are some good resources on Intumescence and Edema.
 
Edema vs. Intumescence
https://ag.umass.edu/greenhouse-floriculture/fact-sheets/edema-intumescence
 
Info on Intumescences
http://gpnmag.com/article/intumescences-physiological-disorder-greenhouse-grown-crops/
 
More detailed info on Intumescences
http://gpnmag.com/wp-content/uploads/08_Intumescences_GPN0914.pdf
Great info guys, thanks! 
 
CD, One of the articles you sent along mentioned humidity as a causative factor. In that the plant can't properly transpirate if the air is sufficiently saturated.  While I do have air movement, I'm growing in a closed spare room. 
 
One last thing to try might be to run a dehumidifier for a while to see if I have any improvement. 
 
What's the "usual" humidity range for mature peppers? (if such thing exists) 70% is high enough to condense on the exterior walls!  :censored:  
 
Appreciate your wisdom!
 
 

CaneDog

Extreme Member
DM, I view this in application very much like PaulG in that I generally live with smaller amounts until the plants go outside and it disappears.  My favorite plant nursery is a walk-in closet I've dedicated to starting peppers and no matter what I do I'll have a small level of general occurrence on many, if not most, of the plants.  Usually no more than a few will suffer more significantly.  I basically try to have good air circulation, not over-water, and space adequately (sometimes hard to do), while keeping my environmental parameters in range.  On the worst ones, I'll cut them back sometimes as that seems to make it go away in the new growth, but it always recurs once the plants have grown back the majority of the foliage - really I'm just "buying" a little time until plant out with these.  I haven't had nearly as much occurrence in grow spaces other than the walk-in closet.
 
Temperature and humidity requirements vary among types, but for many Habanero and Caribbean types my understanding is that optimal temperatures are around 75F/24C at night and 86F/35C during daylight hours with +/-80% humidity.  Here's a good study on temperature effects on Habanero that uses 80% humidity in a controlled environment while determining optimal temperatures.  80% is also a common growing season humidity in many Caribbean locations too, to my understanding.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4218724/  I'd aim for a high humidity for Chinense, but not to the extent of risking mold and damage and such.
 
FWIW, the most affected plant I ever had was a TM Scorpion.
 
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