White Bumps Under Habanero and Reaper Leaves

[thelapua]

I have been growing my peppers in a tent under LEDs in my garage, and I recently noticed these underneath the leaves. Does anyone know what these are? Maybe spider mite eggs or aphids? If so, would neem oil take care of this? It doesn't seem to be impacting the health of the plant so far, however I want to address it now. This picture is a leaf with a little bit of it. There are far worse leafs than this. 
 
 

 

[thegreenman]

Edema?

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[thelapua]

Is there a way to fix this? or is this a death sentence for the plant? What causes edema? I looked online and it said more water uptake by roots than the plant can transpire. I don't overwater the plants. It has been really hot lately, so could that be one of the causes? 

 

[Peter_L]

If you can confirm it is indeed edema (the bumps are obviously in the leaf and not something attached to it), you don't need to worry much; it is certainly no death sentence. The plant is just not regulating it's water intake correctly or conditions make it difficult to transpire enough water to keep up with growth. Edema will just slow growth; plants pretty much never die from it. Eventually older leaves will develop some dead spots where it is affected the most, but the plant will start producing new leaves if the old ones are too damaged.
 
Over-watering, watering plants when it is humid, or consistently letting plants wilt before watering them are probably the most common conditions for developing edema indoors.
 
I'm not sure of your schedule or the actual reason for the edema, but is it possible to water twice as often, but half as much each time? Try it for a couple weeks and see if new growth is unaffected. Also a small fan will help a lot if you don't have one. A little air flow goes a long way with transpiration.
 
Good luck!
 

 

[thelapua]

I have been paranoid about overwatering, so I have been watering them when they start to wilt. I was actually wrong, I am only getting symptoms on my habaneros. The carolina reapers don't seem to have the issue. I have a fan circulating air. The bumps appear part of the leaf, but the color is a healthy looking green. How do you know how much water to give a plant? What else could cause this, pH, nutrient deficiencies? 

 

[Peter_L]

Conditions rarely change much indoors so it's pretty easy to find a good watering schedule in my experience. I take note of how long a plant will go before it starts to wilt with a given amount of water, then water just a little before that. I have 3 pepper plants in very small containers (keeping them small to have for next summer), and I know I need to water ~20 mL every other day. I have 3 slightly larger pepper plants in ~1 quart pots on my desk at work. They start to wilt every 6 or 7 days after 200 mL of water so I water every 4 or 5 days. I haven't noticed any edema for a long time now.
 
When I was growing small plants back in April for this summer and I had ~32 plants crammed in a 24 x 30 inch box, there wasn't much I could do to avoid edema. It's just hard to get proper airflow in such crowded conditions. Some of them ended up with it (maybe 10 - 12), but it all ended up fine, none of them had any lasting problems and they grew new healthy leaves shortly.
 
If your plants still have healthy looking tops of the leaves, I wouldn't worry about it.