| Browning can have different causes. It can be a disease--many fungal infections cause browning. Fungus causes brown spots, brown patches, or even brown leaf tips. Fungal attack can happen quickly, browning whole leaves in no time. Sometimes viruses (and bacteria) can cause irregular brown patterns. More common is sunburn, which is caused by the sun heating up the leaves, destroying the cells, and then resulting in a brown patch. Too much fertilizer causes brown leaf tips that slowly progress upwards, but the browning has "layers" if you look closely.
Usually if the browning is wet and squishy it's fungus and cut it off. Spray with fungicide or put cinnamon on it (it works!). It's safest to separate if it's fungal.
Does the plant get sun? It can be sunburn.
You also said it was in soil. Orchids can't grow in soil, so are you thinking of changing the mix? |