Help with Phragmipedium green hornet

[pismane]

Hello all,

Long time reader first time poster. This is the only phragmipedium I have ever bought, phragmipedium green hornet. I bought it in spike two months ago and so far it keeps producing new buds. Recently a couple of the bottom leaves have started turning yellow which has me worried that it could be water/fertilizer issue and this could be developing into a root issue.

I know these things are really sensitive to dissolved salts in their water and I have been very careful to use distilled water and never let them dry out. I have fertilized with better grow 20-14-13 at 1/4 strength which after a couple of hours I flushed with distilled water. I have been stepping up my game and bought a tds meter and pH meter but not really sure what I need to be doing when I fertilize these. I have not really put much thought into the fertilizer regimen until I bought this plant am not really sure how the math with teaspoons and so forth translates into a specific ppm paramter, or what that even should be for this variety of orchid.

I have it growing on a window in a humidified space with supplemental lighting. It is growing next to a dendrobium spectabile and a box baby cattleya in spike so I have pretty much ruled out a light issue.

Does it look okay or should I be worried? Any recommendations? I really don't want to kill this plant.

[MrHappyRotter]

Looks fine to me.

Phrags are voracious growers. They send out tons of fast growing roots and new growths that literally rip the old, lower leaves off the stem, causing them to yellow like this.

It's also just that time of year when they're blooming and pulling lots of nutrients that are stored in older leaves, so you get a bit of a fall leaf drop from that as well. Nothing to worry about.

[pismane]

Thanks. Just seeing the yellow makes me nervous. How do you fertilize your phragmipediums?

[MrHappyRotter]

Originally Posted by pismane

How do you fertilize your phragmipediums?

I feed very weakly with each watering, usually twice per week. And then at least twice a month, I flush the pots and water only with RO or rain water. The majority of my Phrags sit in water at all times.

I use my EC meter (TDS meter) to test the fertilizer strength and generally keep the reading below 100. For some Phrag species, I keep it much less than 100, and if/when I see signs that the plants may not be getting enough fertilizer such as color streaks or yellowing of upper leaves, then I will increase the feeding rate slightly. When I use supplements like superthrive or seaweed, I follow the label instructions. I don't allow the plants to sit in seaweed extract for more than a day, though.

[pismane]

Thanks so much. I am going to start adding a small amount of fertilizer each weak and flush it periodically.

[estación seca]

A lot of people here on Orchid Board grow Phrags, and discuss how they grow them. If you use the Search function in the top maroon menu bar you can find these threads. Or you can go to the forum for these plants. Click Forums from the left menu, then scroll down to Cypripedium Alliance - Others.

[dounoharm]

i concur with rottie, and I always use some chicken grit from the feed store (crushed oyster) or granite chips...they seem to like that.

[pismane]

Originally Posted by dounoharm

i concur with rottie, and I always use some chicken grit from the feed store (crushed oyster) or granite chips...they seem to like that.

I bought some for my paphs a while back. I will consider adding a little bit when I repot after it is finished blooming.