Scarring on peppers:
[url=https://www.flickr.com/photos/66410587@N07/6045621629/]More scarring[/url] by [url=https://www.flickr.com/people/66410587@N07/]Gothikat[/url], on Flickr
One normal pepper and some scarred peppers on the same plant. Notice the bottom-right pepper is almost completely scarred, and the top-right smaller ones are a little less scarred:
[url=https://www.flickr.com/photos/66410587@N07/6046172982/]Peppers[/url] by [url=https://www.flickr.com/people/66410587@N07/]Gothikat[/url], on Flickr
Leaves curling up
[url=https://www.flickr.com/photos/66410587@N07/6045622369/]More curling of leaves[/url] by [url=https://www.flickr.com/people/66410587@N07/]Gothikat[/url], on Flickr
Under leaves, prominent veins
[url=https://www.flickr.com/photos/66410587@N07/6046174082/]Under leaves[/url] by [url=https://www.flickr.com/people/66410587@N07/]Gothikat[/url], on Flickr
I have a hydroponic set-up with this batch of bell peppers. This is my first year attempting to grow them, as well as dealing with a hydroponic (NFT) system. Everything started out perfectly, we have already picked 2 beautiful, normal peppers from these plants. About 3 weeks ago, I noticed this was happening (see above pictures - scarring on many fruits and leaves curling) and I'm not sure why. The plants have been in this system for about 2 months now. We have 4 pepper plants as well as 4 sweet 100 cherry tomato plants in this same system, and the tomatoes seem to be suffering from Septoria possibly due to the greenhouse roof leaking (a huge hail storm damaged the roof a bit). However, I have read that this does not affect peppers, and the symptoms of both types of plants are very different.
I change the water supply in the system every week or two, depending on the TDS reading I get. I check the reading every 2-3 days and either top off with water or add nutrients, depending on what's needed. I try to keep the TDS around 900ppm as to not burn the peppers nor deprive the toms too much. At first, I'd say maybe the first month or so, I wasn't using a tester - I had a high quality product that included a recipe per gallon of water. When I ran out, I was unable to find the product in my area (I had received a free starter kit the first time), so I purchased a TDS meter as well as a regular fertilizer for blooming vegetable plants (not specific to hydroponic veggies, hence the meter to gauge how much to put in the water supply). The first time I used this fertilizer, I believe I overdid it at around 1300ppm - contradicting information on the web led me to believe that peppers could tolerate up to 1400, and that toms needed about that much. After a few days, I noticed that the leaves appeared to be burnt, so I completely flushed out my water supply and the system, and put in new water as well as lowered the nutrient level (900ppm). This did seem to help and I have been using this amount ever since. I also test the pH of my water, which I keep around 6.4.
However, leaves have recently started to curl, some up, some down, and many of the peppers started showing scarring. I have spent countless hours trying to figure out what happened (at this point I'm not sure it's still related to nutrient levels). I've not been successful at finding information regarding this on the web. I've read that leaves curl either one way or the other, not both ways on the same plant. This affects both old and new leaves. I haven't found much on scarring either. Some peppers are perfectly normal, while others on the same plant are scarred. No signs of pests neither on top nor under leaves, nor on fruits. The roots are white and appear to be healthy and the main stems look good too. All plants are still growing and keep producing new fruits and leaves (new leaves curl too though). They are not stunted.
Any ideas as to what could be causing this? I really like the idea of hydroponics but would like to avoid this from happening again next year. We do have a raised bed on the opposite side of the greenhouse that contains both peppers and toms (the same kind of both) that are not affected by this - that side of the greenhouse does not leak though. I'm not sure what could be causing this. Any help/advice would be greatly appreciated!