Phalaenopsis with black roots, yellowing stem-help!

[JessieC]

I bought a gorgeous phal at a local farmer's market about two weeks ago-over 30" high, six huge leaves, and four flowers at the time. It now has six flowers, though the rest of the buds dropped off. I may have watered too soon after I bought it, though I've gotten better about that. However, many of the roots near the stem look black and have now started growing this white fuzzy mold. One of them feels hollow when I poke it, though the others feel firm. Today I noticed the actual stem, near the base, has a quarter-sized yellow patch, though the leaves look fine. I treated with peroxide but I am wondering if there is anything else I need to do.

I have never had an orchid before, so I'm not sure what it's planted in, but it looks like moss. And there are a ton of very green roots fit very snugly in a plastic pot, which I set in a bigger pot with some fake rocks because I was afraid it would tip over. I don't want to kill this gorgeous plant, so any help for this beginner would be great!

[WhiteRabbit]

Hard to know if blooms dropped naturally from age, draft, or something like too much water. It doesxsound like you have some rotted roots (black, hollow feeling, soft or mushy), while others are still good (green ones). Often orchids (especially Phals) are potted in very densely packed sphagnum moss, which retains a lot of water, and is difficult to not over-water for most people.

Water when the now green roots become whitish/silvery. Since it sounds like your Phal is about done blooming, repotting it into fresh potting media would be a good idea. You can cut off dead rotted roots at that time.

After you have posted five times, you will be able to post photos, which are always helpful.

[JessieC]

Thanks! Any advice on what kind of media to repot it in and where to get it? I've read some horror stories online about getting mold and bugs from bad media.

Also, when I repot, should I cut off any black roots? What if they are only black near the top/stem?

[WhiteRabbit]

Medium fir bark (for orchids) or medium bark orchid mix - I've found at least one or the other at retail nurseries, hardware store, home improvement box stores like Home Depot (haven't been to Lowe's, but they probably have it). Good quality sphagnum can also be used, just not as densely packed. Coconut husk chips are another option. But fir bark chips or mix are the easiest to find. DON'T get the Miracle Gro orchid mix - it's very heavy and dense.
I usually use fir bark chips for Phals as I really struggle to not rot the roots.

If you get just the bark, rather than a mix, you can add a bit of perlite and/or charcoal (horticultural) .

Soak bark in plain water overnight before using it. Fresh bark doesn't retain moisture well at all, and even after the initial soaking will need to be watered more often the first few weeks then it will after those initial weeks.

I use bamboo skewers (for kabobs) in all my orchid pots, to help determine when to water. Gently twist the skewer into the media about midway between center and rim of pot, or as best you can get to that. Check for moisture by removing the skewer, touch it to your cheek. If there's moisture in the pot, skewer will feel moist, or even just cool to your skin. Phals should be watered when skewer feels cool only, or dry, but shouldn't be left completely dry long. Replace skewer into same spot it was previously.

If roots are black at the base, but feel firm and are green, white, cream, silvery further down, they can stay.

[JessieC]

Great, this is very helpful, thanks! Should I wait until the flowers die/fall off to repot?

[JessieC]

Well, this morning when I got up there was more yellowing on the stem and one of the leaves so I pulled it out of the bigger pot...and it was sitting in water! The person I got it from said to give it a cup of water once a week, but over two inches of rocks were still under water! How much water should I be giving it?

I looked at the roots, and they look green, though there is a line about two inches down from the top of the pot where they go from dark green (toward the top) to sort of yellowy-green. I can see one or two roots that look like they-ve rotted--all brown. Is it safe to repot when the last flower just opened last week?

[cbuchman]

Standing in water is not good. It sounds like your bigger pot is for "show". I suggest that you take it out of the bigger pot when watering and let it drain before putting it back in. If there are still healthy roots, all isn't lost.

Most orchids are epiphytes which means that their roots are exposed to the air. Epiphytic orchids require water and drying out (though Phals don't like to dry out completely). The chunks of medium provide air space between the roots to help them breath.

I suggest careful watching and drying out at this point to see if the root rot grows. If it does, you will need remove the rotted roots.

[RosieC]

You don't want to water with a set amount, what you should do is just as Carrie has said, take it out of the outer pot and run water though the pot (it can be lots of water, it should be enough to wet the medium well). Then let it completely stop dripping, then put back in the outer pot. Come back maybe an hour later and tip out any water left in the outer pot. Most orchids and definitely Phalaenopsis orchids don't like being left standing in water.

Unfortunately I've come across a lot of people thinking they should just give a little water each week, however this method either leaves them too dry or too wet. They like a lot of water when you give them water, but then plenty of air, which means being allowed to dry out in between.

All is not lost. Take it out the pot and cut off mushy roots. If they are firm they are good, if they are mushy or hollow they are bad. Once you've done that see how much root you have left (post a picture here so we can advise more). Pot it up into the smallest pot you can fit the roots into. I've used old yogurt containers in the past when I don't have a pot small enough. Small pots help the medium dry quickly a big mass of medium with no roots in it will dry very slowly and that just makes the problem worse. If the pot is so small the plant is top heavy then you can still stand it inside a larger outer pot to balance it.

[JessieC]

Some of the mushy/hollow roots are at the top connected to the stem. Should I cut those away too? Two leaves are dead and the yellow is spreading, and I am going to repot tomorrow. The medium still feels wet even though it has been over a week since I took it out of the big pot and cut holes in the small pot to let it dry.

[JessieC]

Here are photos.