One thing to consider is that the sun isn't out long enough at this time in the season to really tell the plant to go into a full bloom so its okay for the peppers to show signs of flowering but not actually flower. Also, the sun's light spectrum in your area will change as we near summer also stimulating the growth and later triggering flowering.

If you are worried about nutrient deficiency in a POTTED plant, the first thing I would do is FLUSH the plants to remove any nutrients in the soil. The reason for this is that the soil may be out of balance in terms of nutrient ratio. By adding a 7-7-7, the ratio in the soil will not change. If you have a nursery, you can ask about a flushing solution that helps leech salts from the soil, otherwise, simply water the plant until the run off is no longer "dirty" and looks clear. When I propagated inside, we used an old egg crate, placed it over the toilet, stuck our plant in the egg crate and watered until clear... then flushed the water run-off away. If this is your first time flushing, you can expect to use about 5 times the pot volume in water before it clears up. Once the soil has flushed to a theoretical 0-0-0 concentration, allow the soil to dry up for a few hours and then add your selected nutrients (I'd start with 1/4 strength per the label instructions and increase to 1/2, then full strength etc. each or every other week.). Keep in mind that you will look for results in your plant's FUTURE growth. I have never experienced evidence of leaf recovery. The plant often times discounts the afflicted leaves and moves on with new and better leaves. Pinch them off later if they are unsightly.

Good luck!

EDIT:

I hope I don't get into trouble for posting a commercial link, but I use this product for foliage feeding. Its similar to what you are trying to do. The smallest bag will last SEASONS.

Here is a link that might be useful: Sea90 Foliar Feed

This post was edited by LoneCowboy on Fri, Feb 28, 14 at 14:38

Thanks all for the new ideas and advices. Few things to mention:
1. In fact this is my 2nd trial for the 2nd season. The pots have been used once last year. I used the same media after adding new enrichment compost, following the instructions of the nursery.
2. This year I switched the pots: pepper in place of tomatoes and vice versa.
3. All the pepper trees -sorry ... plants- are affected: the latest leaves are curly. The early ones are fine, big and shiny.

NB.
Last year was very unlucky (!!! ???). probably because I started late in Feb (it turns hot by mid-March/April here .. hmmm >90F). I could get few tomatoes from one plant (out of 8), with blossom end rot. The others yielded only flowers. The peppers all died early. Blossom end rot means Calcium deficiency, although the media was totally new, probably because of daily watering (just a guess)
This year I started 3 moths early. Still I am unable to extend the period of sun exposure as I am living in a small villa with lots of shades (from the neighbour buildings and trees). Would a mirror be OK? or just add some lamps?

Lamp Issue: get as much compact florescent light to supplement as is realistic. I personally use a single T5 for sprouts. Were I to supplement for indoor growth, I would get a 4 bulb T5 florescent fixture if not a high pressure sodium (hps) lamp.

I've never tried a mirror... maybe mylar or "Panda Film." Can you show us your growing area with a photo?

@LoneCowboy
Here is the pepper and tomato (there are another 2 pepper + 3-4 Carrots containers not shown). I don't have a lot of choices to place my plants. The tomatoes are doing fine. The maximum sun I can get in one location is 5 hours. Probably I may need to lift them up to get one hour more. Of course I can get more time if I am available to move them with the sun throughout the day :)

If you can get them raised a few feet realistically then yes do that. Otherwise, if you are growing in Saudi Arabia as stated in your profile, you will get about an extra 2-3 hours of sunlight per day naturally in the next few months, not to mention the position of the sun will adjust slightly and probably send light over that fence naturally.

Hi again
I discovered these pests recently on one of my junior peppers. Look like aphids? The others still showing wrinkles but Could not see any pests on them.. With my eyes at least. Do I need a lens? BTW.. I got 2 flowers finally. Hope the better to come yet.
Any suggestion?

It looks like the white, cast off skins of aphids. My guess, without being able to see with my own eyes, is that aphids are infesting that pepper and are deep inside the bumps and folds of the distorted leaves.

Fertilizing via foliar spray doesn't benefit peppers - don't waste your time.

Preferred fertilizer NPK ratio is some multiple of 3:1:2 since that is the ratio that the plant actually uses.

I suggest that the symptom is the result of insect damage. Fine netting does not deter many pest insects, but may well deter their predators. I can't be specific here because I don't know your indigenous fauna.

Good luck. Please let us know how it goes.

Dennis

Hi everybody

Back again after one full year. Just to let you know how it went. I got disappointed and decided to get rid of such STERILE pepper plant. I went into long summer vacation (about 1.5 months) and left the plant to die.

However, the gardener kept watering them while I was away. When I came back, I found at least 8 green peppers. Not believing my eyes, I kept watering and adding fert and foliar sprays, and the pepper continued to show up here and there.

Yesssss @Ken ... Its Patience

Now Its the third year and the plant is still giving peppers, but some of them fall prematurely and still the wrinkle leaves. I don't know yet how to get rid of these aphids. I tried once or twice the Sulphur powder/spray, but I don't know the proper concentration. Any help