orange rusty color on top

High ganzigunnu, I am 100% sure that this is a calcium dificiency. The cause of this deficiency could be pH issues or overfeeding. They both cause nutrient lockout but it doesn't really matter what the cause is. But it does matter that you can fix both of these problems with a good flush of your soil and I will explain you how you can do that the best. You can do this flushing by slowly pour water pH 6.2 onto the top of the soil, allowing it to drain freely from the bottom of the pot. Pour slowly, so the water doesn't overflow from the top of the pot. Use approximately four times the pot's volume in water to flush the soil. For example, use 1 gallon of water for a 1 quart pot. After the flushing you need to let the soil (almost) dry out completely. From there you can start giving water with pH 6.2 and nutrients but do not exceed EC 1.8 to make sure that you don't overfeed them in their last weeks working hard making those buds bigger, fatter and juicy! Happy Growing! 😋