Southern exposure during winter

[Ray]

Ardera, what formula fertilizer are you feeding your plants, and at what concentration?

Bright, emerald green foliage is often an indicator of excessive nitrogen.

[ardera]

I'm at work right now, but if I remember correctly the nitrogen was 13. I purchased this, from our local orchid nursery, this is their own fertilizer mix for orchids. It was 13-5-(something, maybe 15?) 1/2 teaspoon per gallon, once a week.

[ardera]

I should say, I know it is 13-5, just don't remember the last number.

[meganreaux]

I would stick with the wal-mart sheer. I use a simple white sheer curtain that I got from Tuesday Morning on my south window for my phals. They seem to be doing really well-- new leaf and root growth. I would use the sheer for a month or two and if you still feel like they aren't getting enough sun take it off.

[meganreaux]

But I should also mention that I'm in Louisiana and the afternoon sun is probably brighter/hotter here. Maybe in Colorado the curtain wouldn't be necessary.

[ardera]

I'm just thinking that with the sheer, then my catts may not get enough light.

So to acclimate, let me know if this sounds good, or if I should take additional steps.

Week One - Sheer curtain and blinds set, facing up, so light comes up from the ground.

Week Two - Sheers, blinds set to middle, so light comes straight across.

Week Three - Sheer, blinds facing down, so light is coming from sky to orchids.

Week Four - Sheers, open blinds (no longer use blinds)

Week Five - Open sheers, direct sunlight

Would Five weeks be adequate, or should I take this more slowly?

[ardera]

Anyone in Colorado have opinions on this? I was just thinking, we are at an elevation of 5,000+ feet. Human beings burn more easily here, maybe orchids as well? Humans - it is an issue that there is less atmosphere to protect us from the sun.

[Ross]

I think there may be a couple issues being discussed. First the fertilizer issue. I use a fertilizer mix with 125ppm Nitrogen at every watering. I avoid the dark green, nitrogen-induced coloring. The second is lighting. First, my setup is a south window all year, where all plants are exposed to direct sunlight when it occurs. I also use several compact and straight tube florescents. Here is the setup

As to the questions regarding sun in Colorado, keep in mind the elevation and latitude. Colorado air is (for most part) clearer than many other parts of the US and the direct sun is higher in foot-candles as a result. One would experience high sunburn at high elevations. Also in winter, the sun at the northern latitudes is lower in the sky and will shine more directly into south-facing windows.

I personally, would use a good light meter and measure the foot-candles in the proposed window and reduce light to 1500-2000 foot-candles to start. Then over a period of several months remove a layer of curtain at a time until foot-candles reach perhaps 3500-4000 for the Cats and similar. Keep the light levels below 2500 for Phals and Paphs. This is just my personal observations and not meant as general advice for everyone. The leaf color will gradually turn lighter on many of the plants. My Beallara is up next to the window in lower left of the picture and the leaves are nearly yellow from the sun. It blooms regularly (it is in spike right now). The Paphs and Phals are back towards the room where light levels are half that of the Beallara.

Almost forgot, I use three small fans running 24/7.

[ardera]

Ok, so I had to find a Fertilizer PPM Calculator on the net, but I figured out that I am somewhere between 86 - 99 ppm on the Nitrogen. So is this good, or is it too little? I'm assuming that this is ok, as I would figure the higher the number, the more nitrogen, thus more vegetative growth = darker green. Maybe I have this wrong though

So Michigan, at a higher latitude than Colorado, the sun would be lower in the sky, so more direct. But Colorado would have stronger light (higher foot-candles) than Michigan because we are at a higher elevation?

[Ross]

Originally Posted by ardera

Ok, so I had to find a Fertilizer PPM Calculator on the net, but I figured out that I am somewhere between 86 - 99 ppm on the Nitrogen. So is this good, or is it too little? I'm assuming that this is ok, as I would figure the higher the number, the more nitrogen, thus more vegetative growth = darker green. Maybe I have this wrong though

So Michigan, at a higher latitude than Colorado, the sun would be lower in the sky, so more direct. But Colorado would have stronger light (higher foot-candles) than Michigan because we are at a higher elevation?

I prefer a little higher nitrogen for a daily watering/fertilizer regimen. I use 125-150ppm. Higher altitude means less atmosphere between you and the sun thus stronger light. You would be far enough north to notice longer days in summer than in winter (compared to Florida) and the sun would be at a lower angle in winter than summer thus shining more directly into the windows. In fact you should be noticing that now (compared to, say, June). Try getting or borrowing a good light meter and measure to be sure. For Michigan, I measure approx 4000 foot-candles just inside the glass in June/July. In January the foot-candles are the same but the rays reach further back from the glass (think I described that correctly ) but you get the picture.