A topic near and dear to my heart. I learned about pH the hard way after losing many, many plants. Any hobbyist who seeks to grow healthy orchids should take some time to study plant nutrition as it applies to orchids. Generally, orchids prefer a pH in the area of 5.5-6, however, I ignore this rule as different types of orchids prefer varying pH. I water with RO water exclusively and I check the pH every single time I water. I adjust it to a pH 0f 6.5-7 so that the pH remains in the safe zone for nutrient availability when it hits the substrate. I highly recommend you google 'Tom Blackmore' and read his articles on 'Understanding pH management and plant nutrition'.

Raphael, have you ever heard of decalcifacation tablets? If so, have you ever used them? This should bring down the pH of my water, no? Please refer to the article you referred me to (pg 12 of the newsletter) and to Dr. Gustav Schoser's book 'Orchid Growing Basics' pg. 27. Tap water contains a lot of calcium. It leads me to believe the tablets might help as well. What do you think?

Decalcification tablets are normally used to remove Calcium build-up in espresso machines, etc where hard water has continuosly been used. They're not made for plants and do not remove Calcium from water or intended to affect pH. It's a good idea to get a copy of your local water report and find out what is in your water. Most tap water is chlorinated and orchids hate chlorine. Have you ever considered an RO system?

An RO system is way out of our budget for a while. I am a stay-at-home mom of two boys (1 & 3 yrs). The Clear2o filtration pitcher, however, does filter out 95-99% of contaminants including chlorine. I also let the water sit a few days to let the rest evaporate and shake vigorously to add the oxygen back into the water. I'll have to check into that local water report. I didn't realize that was available, but I was raised on well-water from the farm as a kid and have only been in the city for 7 1/2 years. I have a lot to learn. I added the link for the Clear2o. If you wouldn't mind taking a look at the statistics and let me know what you think....

Thanks!

Here is a link that might be useful: Clear2o

There is no doubt that all this stuff about the water PH and fertilizer concentrations can be beneficial, but i question the benefit to a new grower who unless they have some scientific training and experience could get confused.

To my mind it is the icing on the cake, the fine tuning after you have mastered the essentials.

Now, in this City of 4 to 5 million people there are countless orchid growers. They grow reed stem Epidendrums and Cymbidiums as garden plants. If the plants need watering they get out the hose and water them ( on designated watering days). They do not worry about the Chlorine or the PH of the water or how much Calcium there is in the water and i would never mention such things to them. (Them being the public at an orchid show who want to buy something easy to grow like a Cymbidium)

At the other end of the scale are the specialist Cymbidium growers who do worry about the PH of their fertilizer, what micro elements are present in the fertilizer, whether their potting mixture is producing optimum results and so on. In other words the icing on the cake. Note these guys dream about winning Champion Cymbidium at a major show. An impossible dream for most.

For some 35 years i happily watered my orchids with the hose from the tap.Then i got a 3000 Litre rain-water tank so i could water on the days i wanted to rather than designated days. Have to laugh.... the tank came with the sign "Unfit for drinking".

Are my orchids growing any better? Not that i can discern and i have to use a complete fertilizer with micro-elements (including Calcium) to make up for the lack of trace elements in the tank water.

If you have doubts about the quality of your tap water, obtain an analysis of your tap water from the water utility.... and ask the question here....is it OK?

Of course, there are orchids that are very sensitive to water quality. Disa is one for sure and there are others that are probably cloud forest orchids.....i would like someone to produce a list of these sensitive types.

As Arthur states, just collect rainwater. I have a rain barrel which freezes in winter, but I collect snow in containers all over my deck. Takes a lot of snow to make a gallon, but you can mix half tap & half rain water. The plants will be fine. They are a lot tougher than you think.

Jane

You can buy RO water at the supermarket. It will be labeled "purified". If you can't get that, distilled will do. I use half purified and half tap. Works out well.

I only use the half/half mixture when I fertilize. When I do a plain water flushing I just use all tap.

You might try soaking the coffee grounds in some water overnight and then take a reading to see how acidic it made it. You can get test papers at the aquarium store. You can also get chemicals to change the ph at the same store.

I confess to checking the ppm (parts per million) and PH of the solution virtually every time I fertilize. And I use RO water.

There are exceptions if I've used the solution recently and/or have written down the "recipe".

Carol

Acidic things like peat moss, coffee grounds, and vinegar (acetic acid) would all lower the pH. I think checking the pH every time you water is a litle stessful (and as a scientist) I avoid doing that since it reminds me too much of work which I try to escape from with my orchids.

I don't think the pH of the water is as important as flushing, and in the winter I flush with lots of water, after all the bark itself is acidic. Grant it, I have access to RO water which I do use, but I only periodically flush each pot with it (mostly in winter where access to rainwater is hard to come by). This winter we had so much snow in Chicago I actually did throw some into some hot tap and water with that too. Collecting rainwater is good, but I have been known to re-adjust my schedule and just bring the plants outside for a good soaking (even in March or November for a few minuntes)in the middle of a good downpour. I just bring them into a warmer room and let them dry off. I look forward to summer since most of the orchids go outside and I water when I need to with hose water, collected rainwater, and my favorite, pond water, especially since most of the plants are growing new psuedobulbs, the added nitrogen is beneficial. UNless you have a sensitive cloud forest plant, like arthurm contends, I wouldn't worry too much - or am I just a lazy gardener?

Testing for PH and ppm isn't stressful for me, unless I'm really pressed for time, and don't even want to touch the meter. It's a Hannah that tests for ppm and PH and is super easy to use and maintain. I've had it for several years, and my orchids thank me. :)

Carol

Great tips! I do put them out in the rain. I think I'm going to buy some 5gal. pails and put them in the driveway during good rains. I've got the constant humidity needs under control, finally. I bought a 13" round serving tray @ Walmart. It's about 1.5" deep. I mounted the pot on an upsidedown terracotta tray in the glass serving tray, put marbles around and water within. The pH is all I'm concerned with right now b/c I want a bounty of blooms.

Here are the best I've gotten from my Phal. brother x lancer. This was last year.

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