brown leaf tips on phrags

[Big B]

All of my phragmipediums are developing brown leaf tips. The brown is working its way down the leaves consuming the whole leaf. This is occurring on new as well as old leaves. It does not seem to be occurring on my other orchids. I have tried cutting the brown off, but it just continues from the cut. Any ideas what is causing this and how do I control it?

[Lagoon]

Hi B,

Phrags will show these brown leaf tips with to much ferts & high calcium waters, also if you're not watering them enuff.
RO, rainwater or distilled waters really are the best for phrags - some are just down right fussy.

Happy New Year & Welcome aboard

[Big B]

Thanks for the info. I was wondering if it might be too much ferts. Good thing I read your reply before doing the feeding today (1/4 tsp/gal ever second Saturday).

And thanks for the welcome too!

[slipperfreak]

I don't think 1/4 tsp. per gallon every second Saturday would be too much fertilizer. Your water is probably too hard. I will try to find a water quality report for Winnipeg and let you know.

[Big B]

Thank you. BTW, I water with tap water that has gone through the brita filter and then set open for 3 days.

[slipperfreak]

Okay well... to start off if you live in Winnipeg proper it appears your water quality is okay to start off with anyway. Not optimal, but okay. Your TDS is better than a lot of cities (including mine), and the pH isn't brutally high.

Here are the facts:

TDS 102ppm
Conductivity 167 microsiemens
CaCO3 80ppm
pH 7.34

Most Phrags like a pH of around 6, and a TDS around 10-20ppm (very pure water). Large concentrations of calcium and other minerals can burn the leaf tips. Some Phrags are more sensitive than others; for example schlimii, besseae, boisserianum and many of their hybrids are known to be sensitive to high mineral content water. It seems as though longifolium, caudatum and many of their hybrids are a bit more lax, but will still do best with good water.

Brita filters will probably help, but I don't know how much. I have no facts on them. I used to use them years ago, but eventually I just started buying big jugs of RO water. That way you know that you are using good quality water. Because my own tap water isn't horrible (and yours is better than mine), I don't use RO every time I water (except with besseae and schlimii). But I do flush the mix out with it often. For best results, I would recommend you try something similar.

[Big B]

So if understand what you are saying, Winnipeg water is middle of the road and is OK for most orchids. However phrags are picky about water quality and will need better. It would look something like feeding week use regular water and the not feeding week use RO water?

[slipperfreak]

Winnipeg water is actually fine for most orchids. Phrags are just babies . What kind of fertilizer are you using? You can probably up that to every week, especially if you grow your Phrags wet (standing in saucers of water). And what you can do, is you can fertilize and then 2 days later flush the pot out with RO water. Mix the fertilizer with tap water and use tap water when you water except when you are flushing with the RO. It's almost impossible to overwater Phrags, especially if they are in a well-drained mix. So water them often and flush them often, and you will have less of a chance of burning them. It's when minerals exist in a dry environment that you really damage the plant.

[Ross]

Just so you know, the Brita filters cannot remove TDS. Only suspended solids or bacteria.

[slipperfreak]

Good to know Ross. Thank you.