Marks on Dendrobium leaves and stem? (Complete Newbie)

[Teapot]

Hello all!

Complete newbie to orchids so I apologise if this is a common or dumb sounding question; I have looked around online but I am still not sure if it is an actual problem or not.

I recently got given a "Dendrobrium Soft Cane". It has white and purple flowers and I only got given it a day or so ago. I have been looking up on how to care for it but I noticed when I got it that that one of the stems of the plant has marks on the leaves which the others do not.

The leaves seem to have white marks on the top side (they seem to rub off) and smaller white dots on the underside. The stems also seem to be going brown slightly where the leaves are attached. I have included photos of both and of the substrate the plant is in (Sorry if they are not the best quality!) in case it helps with identifying.

Thank you in advance! Again, like I said I am a complete newbie so I wanted to be completely sure if this is a problem or not in case I need to do something to fix it up.

[rbarata]

I don't see anything wrong on the leaves/plant. The marks on the leaves' top side are water drops that have dried and left behind some minerals.
You Dendrobium seems to be a Nobile. Now you're in autumn and they lose their leaves in winter so don't panic when that happens. During colder weather, give it just occasional waterings (or no water at all if the pbulbs, the "canes", don't shrivel too much). Also stop fertilizing by middle of the summer until they resume their growth, after blooming).

[estación seca]

Welcome to the Orchid Board!

Have a look at this thread. It deals with plants like yours:
Need Help with my new*Dendrobium Wave King Akebono

[Shadeflower]

just wipe all those spots off with a damp cloth. If they all wipe off then there is no problem.

The hardest thing will be to figure out how to keep it over Winter in Australia. It does look like a Nobile Hybrid which does well with a cooler winter rest.

I keep mine in a cool indoor room in the UK but depending where in Australia you are this one might do well outdoors in a sheltered location all year for you.

It does like to go down to 10 degrees C at night in Winter time and can handle lower.

Otherwise the care is fairly straightforward and can handle a huge range of temperatures the rest of the year. The hardest thing is keeping up with watering with my Nobiles.

My Nobiles drink the most out of all of my Orchids. 1 liter per month on average per plant and that does not go down by a lot in Winter.
My Aerangis Mystacidii in comparrison drinks 20 ml per month.

So if you forget to water it and the Substrate dries I find the plant starts losing leaves within days. Once a dendrobium had started discarding a leaf even if you start watering again you can't make the plant reattach the leaf, it will drop but by watering it the plant won't shed any more leaves.

Literally 3 days of dryness for my Nobiles and I can guarantee they will start dropping leaves.

Others say Nobiles drop leaves in Winter. Mine don't and mine are the same as everyone elses. They do drop leaves after the leaves are roughly 2 years old.

So once a new cane has grown then the previous years cane(s) will start dropping a few leaves but the plant should ideally not drop all it's leaves as it won't be able to absorb as much sunlight to produce energy.

The people that argue that dens do drop their leaves in Winter are most often also not watering their plants and they say it promotes flowering but that's just old wives tales.

Generally most orchids cannot handle being cold and wet at the same time. Nobiles have no issue with this as they like to experience cold winters but still make sure they have a well draining, airy substrate that is not compacted. In winter time they do drink a little bit less so water them a bit less so the pot doesn't stay waterlogged too long, even Nobiles will get root rot if they are wet and cold for too long.

So that is the challenging part, they drink a lot but they don't like to have wet feet for too long in winter at the same time. If you can master fulfilling those two criteria and give it a cool period in winter then you should have no problem with this plant.

Although they seem to flower a the same time each year based on the change in sunlight in spring it is the night time temperature difference that determines how many if any flowers will be produced by the plant. So a big temperature drop at night is beneficial to encourage maximum blooming.

This is why an outdoor location or a greenhouse is so beneficial for orchids, as long as the temperature does not drop below what they can tolerate then a cold night will help prevent an orchid losing as much energy when it loses energy and a warm day will promote it producing energy when the sun is out. Find a location that matches those requirements.

Nobiles like a lot of sun but cannot handle full sun and should always be protected by shadecloth from afternoon sun hitting the leaves.