Oncidium twinkle leaves browning at the tips

[sweta]

Hi all,

I recently purchased this oncidium twinkle that is close to maturity. It came potted in bark and sphagnum moss. I repotted it in sphagnum moss and bark just to get rid of any possible pests that might have come from the growers greenhouse. Plants seems to be doing fine except for some of the leaf tips turning brown. Also I've notice whitish streaks on some leaves. Is it anything to worry about? Please help. House temperature is at 70F and i use tap water for watering. Pictures are attached.

[Dimples]

White streaks from nursery grown plants is typically mineral spots from overhead watering. If you take a damp soft cloth and carefully rub them, they should wipe off. There are a couple bright white dots in two photos, check the plant for mealybugs. They look like tiny white cottony specks. They hide in cracks and crevices, and can be a complete nuisance if you don’t catch them early.

[estación seca]

Twinkle needs a lot of water. Repotting might have damaged some roots. I would only repot when actively making new roots.

Do you know the dissolved mineral content of your water? You can find the annual water quality report online at your water utility.

[sweta]

Originally Posted by Dimples

White streaks from nursery grown plants is typically mineral spots from overhead watering. If you take a damp soft cloth and carefully rub them, they should wipe off. There are a couple bright white dots in two photos, check the plant for mealybugs. They look like tiny white cottony specks. They hide in cracks and crevices, and can be a complete nuisance if you don’t catch them early.

I'm unable to wipe those white streaks away with wet cloth. Tried cleaning with isopropyl alcohol wipes as well. Those streaks sometimes tend to spread I've seen that in other oncidiums that I have. I hope thats not scale.

---------- Post added at 07:13 PM ---------- Previous post was at 07:03 PM ----------

Originally Posted by estación seca

Twinkle needs a lot of water. Repotting might have damaged some roots. I would only repot when actively making new roots.

Do you know the dissolved mineral content of your water? You can find the annual water quality report online at your water utility.

Yeah I didn't want to repot but I've been dealing with scale on some of my phal and oncidium orchids and its been so hard thats why I'm being extra cautious of bringing in any pests. I'm not aware of the mineral content but the ph is alkaline. I remember checking this with a solution i bought that will show whether water is acidic or alkaline. I have the PH up and down solutions but I'm so lazy to adjust the PH with the up and down solutions. I used to use rain water earlier as we get plenty of rain in seattle area but recently we haven't had any rains and its so much easier to use tap water.

[sweta]

Originally Posted by estación seca

Twinkle needs a lot of water. Repotting might have damaged some roots. I would only repot when actively making new roots.

Do you know the dissolved mineral content of your water? You can find the annual water quality report online at your water utility.

I'm attaching the mineral content information of our tap water. Please have a look.

[estación seca]

Part of the report should show Total Dissolved Solids in milligrams per liter or parts per million (ppm.) That's what we're looking for. The toxins in municipal water are too low to bother orchids.

[sweta]

Originally Posted by estación seca

Part of the report should show Total Dissolved Solids in milligrams per liter or parts per million (ppm.) That's what we're looking for. The toxins in municipal water are too low to bother orchids.

So our water source is ground water from an acquifer and its considered moderately hard, about 90 mg/l (milligrams per liter) as CaCO3 (calcium carbonate), or about 6 grains per gallon. pH is roughly between 7-7.5. Can I use the pH down liquid added to tap water for my orchids so pH is between 5-6?

[Roberta]

I don't think that the tap water is particularly problematical for most orchids. You might want to adjust the pH when you fertilize to improve absorption of nutrients, but for general watering, it should be fine. When I use tap water for fertilizing, I just use about a tablespoon of vinegar per gallon to get the pH below 6.

[sweta]

Originally Posted by Roberta

I don't think that the tap water is particularly problematical for most orchids. You might want to adjust the pH when you fertilize to improve absorption of nutrients, but for general watering, it should be fine. When I use tap water for fertilizing, I just use about a tablespoon of vinegar per gallon to get the pH below 6.

Thanks Roberta. I will follow your advice to adjust the pH of tap water using vinegar. Your orchids look so beautiful😍

[Roberta]

Thanks! Vinegar is gentle (so easy to control), and definitely won't harm the plants... just a little bit of extra carbs.