Vanda Light Requirements
You’ll read this pretty consistently, “Vandas need bright light”; but that literally doesn’t make any sense–like what hell does ‘bright light’ actually mean?! In some places they grow Vandas outside in full-sun apparently, but I wouldn’t dare do that in Canada or the interior United States, as we literally have no cloud coverage on hot summer days which makes the sun’s rays extra harsh, especially if the humidity is relatively low (60% or lower). High temperatures from the sun puts your plants at risk of scorching.
So how much light is enough? General information says that around 3,500 footcandles to 4,000 footcandles is adequate to grow and bloom Vandas. If you don’t have a light meter, you can get an app for Apple iPhones called GreenThumb — it turns your phone into a light meter. It works well and has been tested against professional-grade light meters that photographers use; however, make sure you read the instructions because it’s not just an app you can download and use (and it’s a bit complicated). You need to make a ‘make-shift’ diffuser over the front lens (which is simply a white piece of paper) so that your phone camera isn’t focusing on things and is giving a proper light reading.
If you don’t want to mess around with light measurements, your best option is to put your plant in a South-facing window (if you’re in the northern hemisphere) and then put up a sheer cloth or shade cloth to block out some of the direct sun.
I put my Vanda’s in a South-facing window, in full sun. The caveat to that is that I keep my Air Conditioner (A/C) running all day long to keep the leaves cool, and I have thick-pane windows that block a lot of the heat from the direct sunlight. If you have thin windows or no A/C, I would be very careful about putting a Vanda in full sun, all day long, in front of a window like that.
You can tell if a Vanda is getting enough light by the colour of the leaves.
They should be the colour of green like a granny smith apple; freckling is common as well and will show up as purple spots and ridges along the leaf edges. If a Vanda is yellow, it’s either getting too much light, not enough water, or not enough fertilizer. If it’s a dark green, it’s not getting enough light.
Vandas are a funny orchid in that they don’t tolerate wet roots at all. I once tried a water-culture method (roots go into pure water) with a new vanda that had gigantic and long roots. I let a couple of them dangle into a bowl of water, but within 3 days the roots that were wet had died and changed to an unhealthy green-brown color. Through trial and error I’ve found that the best way to water Vandas is to completely drench the plant two or three times per week.
I believe Vandas absorb water both through both their roots and their leaves. I haven’t seen any information online to verify this, but I’ve noticed that when I water my Vandas and get the leaves wet, about 2-5 minutes later the leaves are completely dry; because of this, I make sure that when I’m watering my plants I drench the entire plant a few times per watering in the interest of allowing the plant to sop up as much water as possible. I’ve heard of people leaving their Vandas to sit in water over night — as of now I haven’t had the confidence to try that; if I try that later, I’ll update this post.
Video: Watering Vandas:
*This is a very informative video on Vanda watering by a fellow vlogger (Bumblebee) on YouTube. This single video helped change my perspective on Vanda care and is why I’m able to keep them now.
Video: Vanda Care according to industry leaders, Motes Orchids in Florida
*This is my second favourite Vanda video; it’s long, but it’s packed with lots of valuable general Orchid-care information like parasites, watering and fertilizing.
Everything online says potting Vandas is NOT OKAY and that they’re ONLY supposed to be grown bare root. It’s hotly debated in the orchid groups I follow as well, but I don’t care what other people say. I can’t keep my Vandas alive if they’re bare-root…I’ve tried–they die. I have found that when the plants are fully exposed like that in a low-humidity climate like mine, they desiccate and are dead within 6 weeks. I’ve had the most success potting my Vandas in wine corks which is then topped off with sphagnum moss to hold the humidity in.
Vandas in Full Water Culture (FWC)
I’ve see a lot of people talk about the success they’ve had with FWC (which is when you pot a Vanda in a vase and let it’s roots sit in water), but I haven’t tried it myself and when I explored it, the root tips died, so I cannot comment. I have also not seen anyone have long-term success with this method which makes me think most people eventually run into issues with FWC that leads to the plant’s death. I could be wrong. Here’s a good forum discussion on Vandas in full water culture. And a video from a vlogger who’s had some success.
If you’ve personally had success with FWC on your Vanda, reach out and let me know.