Paph "Angel Hair" Leaf Mottling
 

I have a baby paph "Angel Hair" (St. Swithin x Sanderianum). It seems to like warm temperatures and low light and I'm trying to give it that. It is indoors (I'm in Canada - it's -11C outside) and I keep the room in the low to mid 20s. It is not in direct natural light and I don't have proper grow lights, but I am keeping the room light (a single LED bulb in the middle of the ceiling) on all day to provide some light for this and for my phals and other orchids.

I am getting worried because one of its leaves is noticeably getting mottled, and it only has 3 leaves. I water it regularly but the pot you see in the picture is only 1.5" across so it doesn't hold much moisture.

What do you think? Mottling bad or normal? If bad, what would you suggest? Less light? Higher temps?

Unless it is of very high wattage, a single LED lamp in the middle of the ceiling is likely not much better than no light at all.

However, I'd bet you're seeing a nutritional deficiency as much as anything. What is your water source and what formula/concentration/frequency are you feeding it?

I haven't fed it since I moved in early May. I have been giving it plain tap water, which is treated lake water and doesn't have a lot of dissolved minerals. I used to give it very weak Schultz orchid fertilizer (15-5-5) and occasionally I would break up calcium & magnesium tablets and stick a few of the pieces into the pot. I guess I should start doing that again? I thought you weren't supposed to fertilize orchids in the winter.

No fertilizer since May; I agree, nutrient deficiency. Some multifloral Paphs may grow all year if conditions are correct. It's not getting enough light, either.

Start fertilizing and do what you can to improve the light. What size measuring spoons do you have? You can use balanced fertilizer with micronutrients and at a different watering Epsom salts for magnesium.

The orchids that don't get fertilizer in the winter are the ones that slow down and pretty much stop growing.(Often even drop leaves) If a plant is growing, it needs fertilizer. So this is where you have to get down in the weeds a bit and learn the details of the different types of orchids, and their widely differen needs. Same for repotting... the time to do it is when new growth is starting. Some are highly seasonal and are not happy if repotted at the wrong time. (Some do root in the winter or fall... the "right time" is not always spring - observe, and let the plant "tell" you the right time). Others are growing all the time, and therefore can be potted at any time. (Example Phalaenopsis... they can even be safely repotted while in bloom, and likely won't even drop the flowers) Paphs are in the "always growing and rooting" group.

Thanks everyone for your help. The only orchid fertilizer I've ever seen is Schultz's; it does have some micronutrients: chelated manganese, zinc, copper, and boron. I will get some epsom salts, too.

You don't need to get orchid fertilizer. Plain old Miracle Gro or equivalents do fine. So do many various mail order orchid fertilizers.

And buy a granulated solid fertilizer, not liquid. No sense paying for water.

Use about 0.5-0.6 ml/L of that formula, weekly.