Head swimming with questions about water

[bethmarie]

I've done a lot of reading, and some of it is contradictory. So I'm asking, what's the best water for my orchids? I've been using RO, but found a quote from Ray from a few years ago on OB ("If you water a lot with RO, which has no dissolved minerals, that gradient is reversed, and you can actually pull nutrition from the plant. I don't believe it's an issue for the occasional flushing, but don't make a habit of it.") That has made me wonder if RO is robbing my plants of minerals. Distilled, I assume, can do the same, being nearly pure of minerals. Is there any solid agreement on this issue? I'd sure like to settle on what kind of water and get on with growing.

thanks!

[Bill U.]

Hi Beth, I think this is an excellent question! I am no expert, but in the readings that I have done in the past, they have said that if using RO a lot, it is important to make sure that you are using a very balanced fertilizer, like the MSU formula, to provide those essential minerals and nutrients. Basic Biology would say that without fertilizer, the RO would pull the nutrients from your plants, but this may not be the case.

Ray would be a great person to ask about this, but he won't be back for a while. Hopefully someone else can be a more solid source!

[WhiteRabbit]

I just use tap water. That said - if using RO or distilled for watering, add a bit of tap or well water to it to add minerals

[spetrizio]

It is not good use RO without fertilizer which have enough Ca and Mg and also other microlements.

I had problems with Cattleyas using rain water with fertiliser which have various microelemnts but not Ca.
New grows turn black. it looks like root rot but it was calcium deficiency.

Images of Calcium Deficiency on Orchids

MSU is the best solution.
If you are adding tap water like WhiteRabbit said, it would be nice to know how many and which elements are in your tap water. For Ca and Mg you can find testers for aquariums, or you can find some lab which is able to do full analysis. if your water is hard (180-200 mg/L) you can add 30-40% of water.
another solution only for calcium is to add lime powder or crashed egg shells into medium.

[plumania]

spetrizio, glad I saw your link on calcium deficiency. Looks like 3 of my plants have same problem. Is there any product I can use that supplies calcium?

I have been using regular tap water with various fertilizers and sometimes MSU .

[cbuchman]

I saw the pictures too and I probably have the same problem. How do you add calcium? I use regular tap water and a variety of fertilizers. I just started using fish emulsion. Will that supply the calcium? (I only use FE outside - it's smells too much for indoor use.)

[spetrizio]

if you are using tap water it is not big chance that you have calcium deficiency problem. Ok, it depends on tap water quality. My water in Croatia is very hard, arround 200mg of Ca+Mg per litre.

I could not find any Ca suplemental product. even I did not find dolomite lime which is reccomended. so I have used egg shells crushed into powder, sprinkled in medium.
also I have started to mix tap water with rain water, and now I am using MSU fertiliser for RO water. I did not notice new problem. so far so good.

The fastest way to discover water hardness is to go to pet shop and buy Ca + Mg test for aquariums. test it without and then with fertilizer to see difference. result should be not under 80mg/L (80ppm).

Root rot could have the same or very similar symptoms, and is more often then calcium deficiency.
For that you need fungicide, and stop overwatering.

I suppose that you do not have water softening system on your tap water. in that case you can not say that you are using tap water.

[tucker85]

I use regular tap water. Some of the orchid books that I've read say that if your water is safe to drink it's safe to use on orchids. Some phrags are apparently sensitive to water quality but I don't grow those. If you use RO or rain water it's a good idea to use a fertilizer that contains all the micro-nutrients. Most good fertilizers include them.

[RosieC]

I know Ray does recomend RO, but he recommends the use of something like MSU fertliser with that or rain water or any purer water source.

Ray is the best person to clarify his advice but he's away for a bit I'm afraid.

I use tap water on many of my orchids, with rain water for the more sensitive ones. I use a rain mix fertiliser which is the European version of MSU when I use rain water.

[bethmarie]

Appreciate all the help! I'm experimenting with Ray's SOLO, which can be used every 2 weeks with any type of water. For regular watering, it's RO or rain with 10% tap added. I guess the orchids will let me know soon enough if they like what I'm doing.