I would definitely check your medium's PH as Antics suggested, and if able try to measure the run off PPM to get an idea of whats going on in there.
I would say due to the scorching it looks more like a potassium deficiency than anything else, but given the fact that we don't have more info, its just educated guesses for everyone.
Could you give us a little more backround info? what kind of nutrients/soil/ph/when it started/distance of lights etc...
Could wood ashes solve this problem? As i know they have 0-1-2 npk value. Also wood ashes increases ph so I would add pine needles to decrease soil ph to balance it between 6,5 - 6,8 . Is it a good idea?
I'd personally avoid things that will alter your PH until you have some experience in composting and mixing soils. Always try to avoid experimenting on a good plant unless you have a bunch of other plants.
I have also read that pine needles do not affect PH as much as people initially thought they do. I was contemplating using them for PH control, but when I found that information, I opted to use PH down instead.
Potash (potassium carbonate) - Potassium is widely distributed in nature, occurring in rocks, soils, animal and plant tissue, and the water in seas and lakes. In gardening practice, materials such as wood ashes, tobacco stems, seaweed, potash salts, greensand, and ground rock potash are used alone, in combination with materials yielding other nutrients, mixed with manure, or used in compost piles. Because the potash-bearing materials vary so much in composition and rate of decomposition, specific application rates must be determined for each material and its combinations. In general, ground rock potash at 5 pounds per 100 square feet may be broadcast over the soil surface three weeks prior to planting and spaded in.
I think you could use the whole banana, the recipe I know calls for 4 banana peels, 2 tablespoons of molasses/brow sugar and water... Not sure if one whole banana or two. I think one would be a safe place to start experimenting
Made tea of banana peels allready, later I will try with whole banana. I also made some tea out of potato skins, and planing to use both potato and banana tea. Sounds good? The plant looks really bad and leaves are rapidly falling off.
At first I tought you guys were right about this being potassium deficiency but now I think I have made mistake by feeding her even more nutrients because this looks more like nutrient burn to me. Take a look at these pictures and tell me if you still think this is potassium deficiency.
They do appear to be burned. First step is to always flush to get back to a baseline, then re-introduce nutrients at half strength once the medium is dry and ready for feeding again. Deficiencies are usually caused for one of 2 reasons; 1, there is not enough of the nutrient available in the medium; 2, another nutrient in abundance has locked up the nutrient you are deficient in. It is said so often that it is assumed to be general knowledge that a flush is the first step, and that is probably why no one mentioned it in this thread(including me). If they are still hanging on, start with a flush if you have not already. Make sure to use at least 2x the amount of water as the size of the pot you are growing in. And double check the PH as you go.