Blossom drop is evidenced in many forms. It can result from simple lack of polination, excessive stress of cold, heat or dehydration or it could be a result of a disease. It is difficult to tell from the picture what you are experiencing with this plant although the overall plant looks healthy.

That is a potent fertilizer and so a little will go a long way. Excessive fertilizer acts like any salt in stressing the plant. Furthermore the Nitrogen sources- Urea and Ammonia are more stressing than a Nitrate form.

I'd keep a close eye on the next blossom cluster and watch for signs of wilting or see if the blossoms proceed through a normal opening, yet drop later without forming fruit. You possibly just did not get pollination and you could assist that by placing your electric toothbrush (running) at the base of the blossom clusters for a brief period when blossoms open. Since you have plants in pots it would not be too difficult to flush out some accumulated salts by an episode of repeated top watering allowing the water to drain away. Then return plant to rack and hold off fertilizing for 3-4 weeks.

I agree that is a very potent fertilizer, especially if it is being used at full strength on a container plant. Try diluting it to 1/4 strength and use it carefully.

The stress of growing in such an artificial environment can be enough to trigger blossom drop. Add any additional stressor to that and it is almost guaranteed. Clearly the plants are quite leggy and stretched so insufficient light is one issue they have to deal with and the light spectrum required for blooming and fruit-set is another. Container size is another stressor.

Good luck.

Dave

Thanks for the thoughts. I went out today and bought some fertilizer designed for fruiting that is a 2-8-4 and flushed the plants like bmoser suggested. I will give it a shot and keep an eye on them over the next few weeks to see how the second set of blooms act.