tap water versus filtered water - Orchid Board

siannevo · #1 06-17-2009, 03:44 AM

I heard somewhere that one should only use filtered water for their orchids...is this true? And is there also a preferable temperature to the water? And lastly, if I live by the coast, do you think it wise to put a humidity tray underneath the orchids? (and by humidity tray I mean a tray of water and pepples, or the likes, that the orchid would sit on top, not submerged in.)

Thanks

camille1585 · #2 06-17-2009, 06:37 AM

I think it completely depends on the quality of your tap water. Some places (like NYC) have exceptionally good quality water, and where I am it's very good as well. I've never heard about using only filtered water for orchids. One thing I know not to use is softened water, as the softener replaces the calcium and magnesium in the water by sodium, which can build up to toxic levels very quickly in the plant.

RosieC · #3 06-17-2009, 08:17 AM

I know the water filters we use here add other chemicals to the water as well as taking some away. I think they do usually soften the water as well because we are advised to use filtered water in things like our coffee machine to stop it scaling up.

I would check what yours add before using filtered water.

Here I use tap water for the orchids all the time. We have quite high quality water which I don't drink withough filtering due to a slight clorine smell from it, but my orchids have never seemed to mind.

Ray · #4 06-17-2009, 09:14 AM

As these two ladies have so clearly explained, "it depends". (By the way, that is a phrase used very heavily in the orchid-growing world.)

There are a lot of water-quality factors to take into account, and there are filter factors, as well.

Mechanical filters remove suspended sediment, but that's all, so do not really affect water chemistry.

Some (not all) orchids are particularly sensitive to the mineral content of the water. No filter will affect that. To reduce that, you will have to go to distillation, reverse osmosis, collected rainwater, etc. Some beginners buy spring water for their orchids, but more often than not, spring water is quite high in dissolved minerals, so it's no advantage to use it.

Chlorine is not an issue, as if you leave the water standing in an open container, the chlorine will dissipate overnight. If your municipality uses chloramine however, you're definitely going to need a filter (charcoal?) to remove it.

Organic compounds in the water are likely more of an issue for you than the plants, so if it's OK for you to drink, it's OK - in that respect - for the plants.

pH of the water and your fertilizer solution can also affect plant nutritional uptake and growth.

But before you can decide whether you need to treat your water, or just how to treat it, you need to know its chemistry.

If you have municipal tap water, your provider can give you a report, but you might also rely on a water quality lab to test a sample. I am on a well, and lab testing told me that the quality varied a bit over the course of the year, so I went with reverse osmosis, and have never looked back.

As to humidity trays, please read this: Evaporation

RosieC · #5 06-17-2009, 09:25 AM

Good advice Ray.

I don't know what you have in the States but here in the UK a lot of people use filter jugs. You add water to the top of the jug, it goes through a filter and fills the bottom of the jug which you then pour in to your drinks.

That is what I think of when I hear 'water filter' and it uses charcoal and other things to filter the water. I don't know what it removes, but the booklet which came with my latest jug warned that it adds something (can't remember what but it may have been magnesium) and that some people may have health issues which mean they should not use it.

Anyway our tap water is suitible for drinking but the water from these jugs tastes nicer. I've never tried it for my orchids and was actually more worried about what it may add which may harm them.

Ray · #6 06-17-2009, 09:37 AM

If it adds mag (I think that's doubtful, but who knows?), that would be a benefit to the plants - assuming the pH isn't too high.

RosieC · #7 06-17-2009, 09:50 AM

I'll check what it was when I get home. I'm sure we kept the booklet.

Zdenglan · #8 06-20-2009, 03:29 AM

Hi all, I have tried to water my plants with water from one of these filtering doodaahs and it was not good. When i used it for misting it left white residue on the leaves. That can't be good for sure. It's mineral salts of some kind that are added during the filtration process. Currently I use water that i boiled over in a kettle. That gets instantly rid of all chlorine and some of the minerals as well. Allways using tepid water that has ambient temperature. My plants seem to be loving that. However thinking about investing into a reverse osmosis kit - that I think is the way to go for totally pure water. Costly though...

siannevo · #9 06-20-2009, 03:45 AM

So after much research, I found that a lot of it comes down to a person's individual water. One of your guy's water could be much better than mine, so the first thing to do would be to test one's water levels. A cheap way to do this is buy a EC/TDS meter. It is not super accurate, the more accurate way is to get the City (if you have city water) to do a reading for you. If it turns out your water is horrible, then its best to either buy distilled water and mix in equal parts of your tap water or use rain water (but for some of us we dont always get a lot of rain, I may live by the beach but it rains here maybe one month out of the whole year.) A lot of people do neither and just wait to see if something happens to their orchids before they take an initiative, and then its trying to find out if its the water or the fertilizer. Reverse Osmosis sounds awesome, but only for super serious collectors who have many many orchids...but if this is not the case I would love to know peoples RO experiences. I only have six orchids, and if I hit 35 perhaps I will think about this option, but it seems to have some severe drawbacks. There is a lot of wasted water, it can corrode your pipes, and you need to dilute it with fertilizer. So for the moment RO doesnt seem like such a good idea for someone who rents their apartment and doesnt have an extensive collection. So far I have not seen any salt problems from my water, but I did notice a little bit of a salt problem from a feed I was giving to one of my plants, so Zdenglan you might also want to check your fertilizer, but you seem to have found a way that works for you. And that is the number one thing that most materials I read said...you have to find the way that works for you and your orchids in whatever location you are living in.

Thanks everyone for your feedback. Now its down to trail and error...eek.

RosieC · #10 06-20-2009, 05:45 AM

Ok, I finally remembered to take a look at the details of these water filters.

As I said before when I hear 'filtered water' what I think of is these 'Active Filters' which are very common in the UK.

Brita make the ones I have but there are other makes that are very similar in the UK.

They have charcoal and other stuff in them and according to the details they remove...
Chlorine
Limescale
Aluminium
Heavy Metals (like Lead & Copper)
certain pesticides and organic impurities

As a side effect they add...
Silver
Potassium

They state on them that the water must already be 'from supplies which have been tested as safe to drink'.

Well if it's potasium and silver that they add then I would guess they are safe to use on the plants. But are any of the heavy metals they remove actually good for the plants?