Foliar feeding in s/h

[magicatt]

Is it ok to foliar feed when doing the s/h method? There is always a little fert in my water so would foliar feeding just be too much?

Also does aquarium salt have magnesium in it? Is that good to use with s/h? I'm in need of expert advice before I do anything to my orchids...

[billc]

It's probably ok to foliar feed in s/h, but I don't think there's any real benefit. I have species phals mounted, others in s/h, and others in CHC. The mounted ones get drenched, leaves and all, while the others just get watered through the mix. They all grow about the same.
Unless you have real good air flow(fans 24/7) I would be careful about leaving the leaves too wet. That's just asking for trouble.

Bill

[Ray]

Actually, foliar feeding in orchids is mostly a waste of time for several reasons.

For one the number of leaf stomata in orchids is very small compared to most terrestrial plants, so the adjacent cells where foliar uptake occurs (I can't recall what they are called at the moment) are few and far between.

Then there's the fact that most of them are on the underside of the leaves.

Most orchid fertilizers use nitrate- and ammonium-based nitrogen sources, rather than urea. They are not absorbed well through the leaves, because the ions are fairly polarized. Urea, being far less polar, is absorbed more easily through the leaves, but cannot be directly absorbed through the root system.

You mentioned that you use a "little" fertilizer with every watering. If that "little" is defined as abut 50 ppm N or more, you're fine.

[magicatt]

Thank you both.

Ray, I use your calculator on your website. Which by the way is an invaluable tool for me. Along with all your other information. Your the one who got me to try semi hydro in the first place.

[Vanda lover]

Don't use aquarium salt for your orchids. It isn't the same thing as epson salts and it could kill them.

[tucker85]

I had a group of orchids that I used foliar feeding only for several months. They didn't grow as well as my orchids that received fertilizer in the medium. They perked up immediately when went back to fertilizing the medium.

[Zoi2]

Originally Posted by tucker85

I had a group of orchids that I used foliar feeding only for several months. They didn't grow as well as my orchids that received fertilizer in the medium. They perked up immediately when went back to fertilizing the medium.

I did a similar experiment and had the same response.
Joann