Change substrate of a stressed plant

[epifit]

I have 4 orchids in sphagnum moss with some dead roots. I want to switch them to a mix of bark and coconut husk and cut the dead roots.

Yesterday I bought a LED lamp to compensate the light coming from the window. I watered them recently and they are still wet.

My question is : Is it better to let them get used to the LED light and let them dry then change the substrate or I can do it right now?

[Dimples]

Getting used to improved lighting shouldn't be stressful for a plant. If it is stressful for the plant, that typically means the lighting change was made too quickly. Repotting wouldn't normally impact that transition unless the plant is in bad shape, and if that's the case you'd be better off repotting asap anyway.

So, my vote is to repot now. I prefer removing sphagnum from phal roots when it's wet. Wet roots are more pliable/flexible too.

[estación seca]

Yes, you can repot now.

[Roberta]

Be conservative when it comes to cutting dead roots. It isn't always obvious as to what is "dead". If the velamin (the coating on the outside of the root) comes off easily you can remove it, but if the core of the root is not rotted, it can still hydrate the plant, and at any rate can help anchor it in place in the fresh medium. Having the plant held firmly in place is vital for new roots to grow without damage, so leaving the core of old roots in place facilitates that.

[Ray]

If the plant has been growing in sphagnum, it’s existing roots are “attuned to”, or “optimized for” growing in sphagnum, and will not be for a different potting mix. That means the existing roots will start to fail, and the plant will need to grow new roots that are attuned to it.

For that reason, the ideal time to repot is just when new rots are emerging from the base of the plant, but if waiting risks losing more roots and possibly the plant, go ahead anyway, but be prepared to “baby” it a little by keeping the plants warm (a seedling heat mat works great) and humid, to slow water loss. I just invert a clear plastic bag over the plant and pot (unsealed) to act as a mini greenhouse.

[epifit]

Thank you very much for the help.

Will it help to add a little orchid fertilizer (1/4 concentration)?

[Roberta]

Originally Posted by epifit

Thank you very much for the help.

Will it help to add a little orchid fertilizer (1/4 concentration)?

If the roots are bad and the plant can't take up water (with or without nutrients), fertilizer is of no use. Think of fertilizer as "vitamins" not food... green plants make their own food (carbs) through photosynthesis. It can coast along without fertilizer for a long time, when new roots appear, it will be able to utilize the fertilizer. At this point, follow Ray's advice to maximize humidity so that it doesn't desiccate, and let it do its thing.

[epifit]

Originally Posted by Ray

If the plant has been growing in sphagnum, it’s existing roots are “attuned to”, or “optimized for” growing in sphagnum, and will not be for a different potting mix. That means the existing roots will start to fail, and the plant will need to grow new roots that are attuned to it.

For that reason, the ideal time to repot is just when new rots are emerging from the base of the plant, but if waiting risks losing more roots and possibly the plant, go ahead anyway, but be prepared to “baby” it a little by keeping the plants warm (a seedling heat mat works great) and humid, to slow water loss. I just invert a clear plastic bag over the plant and pot (unsealed) to act as a mini greenhouse.

Is it ok If I use a transparent but blue recycling bag?

[Shadeflower]

Roberta, have you read this article yet?

Why You Should Foliar Feed Orchids (& How To Do It Right)

As the forum mod you should be checking what I post. If you still feel the same about your answer then I don't know what more to say.

So that article exlpains it better than I can but orchid mist does not need to be used exclusively on the leaves.

It can be poured straight out of the bottle into the pot, it is ready diluted, ready to use straight out the bottle in a safe concentration that won't burn roots or leaves.

PS: light looks good, might be a bit close, how strong is it?? If over 10 watts move it a bit further from the plants to start with and move gradually closer to find the right distance

[camille1585]

Originally Posted by Shadeflower

Roberta, have you read this article yet?

Why You Should Foliar Feed Orchids (& How To Do It Right)

As the forum mod you should be checking what I post. If you still feel the same about your answer then I don't know what more to say.

Please stop with the passive aggressiveness, it's not enjoyable for anyone to have to read such comments. Mods are not obliged (and don't have time) to read absolutely everything that is posted. Our job is to try to ensure everyone plays nicely in the sandbox.

While foliar feeding may work for some big names in the orchid world as cited in the article (and they likely have more time for complex feeding regimes), to me it's simply overcomplicating matters:

* 1) Orchids are slow growers and rarely show micro nutrient deficiencies, providing that they are already getting some (as part of tap water or complete fertilizer).

* 2) For CAM type orchids (Phals and many other orchids) the stomata are only open at night, and most are on the undersides of the leaves. This means waiting until dark to spray/mist the plants. That brings the problem of being able to do that (good luck mid summer when its completely dark at 11pm!), taking the time to spray both leaf surfaces, and the issue of plants being wet at night, especially in cool climates.

* 3) While using fertilizers which have the right concentration right out of the bottle is nice and convenient, it is also extraordinarily expensive compared to buying a concentrated fertilizer and diluting it yourself.

* 4) For the vast majority of growers, especially people like the OP who do not have tons of experience, using a decent fertilizer in irrigation water on a regular basis and at a suitable dosage is going to work just fine.