I planted 4 dwarf bean plants from seeds. It's been three weeks and they were doing pretty well. Recently I've noticed that the tips of the leaves are drying out and curling inwards, or tearing at the edges. I have been watering these plants but I'm conscious of overwatering. About two days ago I gave the plants some diluted hydroponic fertilizer. However the problem was present before I put the fertilizer on the plants. I also examined the leaves and couldn't see any pests. The climate where I am is subtropical humid. I would love to save my bean plants and any help will be so appreciated!