Oncidium twinkle leaves browning at the tips

[estación seca]

Dissolved solids of 95 ppm is fine for most orchids. If I had water pH 7-7.5 I wouldn't adjust the pH with acid; I would use a low dose of fertilizer at every watering. Try mixing 1/4 tsp into a gallon of water and check the pH.

[Roberta]

Originally Posted by estación seca

Dissolved solids of 95 ppm is fine for most orchids. If I had water pH 7-7.5 I wouldn't adjust the pH with acid; I would use a low dose of fertilizer at every watering. Try mixing 1/4 tsp into a gallon of water and check the pH.

I think the OP said that it wsa 90 ppm hardness as Calcium carbonate... so TDS would be higher. Still fine for most orchids, but stubbornly high pH... balanced fertilizers like 20-20-20 have phosphorus that tends to drop pH but are no match for honest real-life hard water... that's where I came up with the vinegar adjustment when fertilizing.

[sweta]

Originally Posted by estación seca

Dissolved solids of 95 ppm is fine for most orchids. If I had water pH 7-7.5 I wouldn't adjust the pH with acid; I would use a low dose of fertilizer at every watering. Try mixing 1/4 tsp into a gallon of water and check the pH.

Actually I didn't think about how adding fertilizer might change the pH. I'm currently using repot me fertizer so not sure how that will skew the pH. Maybe I should add fertilizer and then check the pH and if its high then bring it down with vinegar?