Brown spots on leaves

[Wackomaster]

Dear members.

My oncidium is showing brown spots starting from the tip on almost every leaf. Do you guy knows what it is and how I can treat it?

It used to be in direct sunlight before so I thought of sunburn?

Thanks in advance!

A worried noob

[estación seca]

Welcome to the Orchid Board!

Spotting like this is usually caused by insufficient watering or by too high levels of minerals in the water. How are you watering? Are you fertilizing?

Sunburn tends to be on more horizontal leaf surfaces.

[realoldbeachbum]

Welcome to the OB, Wacko! I am new to orchids, so not in a position to provide advice, but these fine folks here on OB will be able to identify the problem.

I have an oncid that has the same brown leaf tips as yours, so I am very interested in their advice.

Happy growing. ROBB

[estación seca]

Water moves from roots to stems to leaves. It evaporates out the leaf pores, leaving behind any salts carried from the soil.

Leaf tips and edges are the farthest from the stems. With insufficient watering all the available water evaporates out pores closer to the stem, so tips and edges wilt, then die. You can see this in leafy plants during hot, dry spells. Japanese Maples are well known for this.

Excess salts are carried out the leaf, and concentrated at the last spots from which water may evaporate - tips and edges. If the solute concentration rises too high, it kills tissues. Aroids grown as house plants, like Spathiphyllum, peace lily, are known for this. They use a lot of water. They are big, so people never take them to the sink to water heavily, flushing out salts. People rarely repot often enough. Salts build up in the soil, and leaf tips turn brown. That won't go away, but if repotted into fresh medium, new growth will be normal - until the salt builds up again.

[realoldbeachbum]

Thank you, ES! I must not be flushing my oncids often enough. Will correct that.