Oh control, How?

[Matorchid]

Hello all,
How would one control PH without chems? I already know of lyme and wood, is there other things that one could use to make mixes more acidic or more alkaline?

Thank you in advance for your reply!

[cbuchman]

I use a few drops of white vinegar to lower my Ph.

[Matorchid]

You would do that in the soaking process or in watering? And how bout making it more alkaline?

[Orchid Whisperer]

Originally Posted by Matorchid

You would do that in the soaking process or in watering? And how bout making it more alkaline?

Just about any municipal water supply is adjusted to neutral pH. So, if the pH is too acid, mix with tap water.

Remember that a low dissolved solids water will change pH a lot in response to anything added to adjust pH (because low TDS water has lower buffering capacity)

[Ray]

Originally Posted by Orchid Whisperer

Just about any municipal water supply is adjusted to neutral pH. ....

Sorry, OW. That's just plain incorrect.

As I've been traveling about on my "Water quality/fertilizer/addit1ves" speaking tour, I have been checking the EC/TDS & pH of local water supplies, and haven't found a single one at pH=7. In Pittsburgh about 3 weeks ago, I saw some at pH = 5.7-6.5, and other samples at 7.5-7.7 and TDS range around 125-175. I was out at the Suffolk OS (Long Island) about a week ago, and the pH there was a pretty consistent 5.5-5.7, with TDS ranging from 25-75 (lucky so-and-so's).

Shifting back to the original query, I have two comments:

1. Everything that affects the pH is "chemical" (including vinegar).
2. The pH of the solution going into the pot is not nearly as important as the pH within the pot, and that is determined by a combination of the solutions, the nitrogen source in the fertilizer, the potting medium ingredients, and the plant itself. Collect the pour-though when you water and test that. If it's in the 5-7 range (preferably 5.5-6.5), it'll be fine for almost all orchids.

A low-TDS water supply at almost any pH is better than one adjusted "perfectly" with higher TDS. Don't forget that anything that goes into solution to adjust the pH will raise the dissolved solids content.

[ALToronto]

I'm surprised that so many municipalities have low pH water. Usually municipal water pH is adjusted at the water treatment plant to be above 7.0 to minimize rusting of the pipes and pumps. Values over 9 are not unheard of.

Fertilizer alone is usually enough to drop pH to acceptable levels, while lime (primarily calcium oxide, which becomes calcium hydroxide when dissolved in water) will raise it.

[snowflake311]

I have been keeping fish and aquatic plants for years and have bred fish. So ph and how to control it I know well.

Peat moss or peat moss pellets are a good way to bring the ph down. Calcium shells can bring up the ph.

Another way would be to water your plants with RO aka Reverse Osmosis water or rain water. There are little to no This water can have a ph of around 5.

Why are you messing with the orchid ph? What kind of potting mix are you using? I found when keeping fish and freshwater shrimp that messing with ph is not worth the time and energy. Maybe that's why I stopped raising freshwater shrimp.

[Matorchid]

While I haven't done a hard test on my tap. Upon doing some research of my city water it runs a ph of around 8.6, with a 600+ TDS. From my understanding most Orcs like a range between5.5 and 6.5. I usually use distilled water but moneys are very tight right now. So I was thinking tap water, filter, then ph adjust for the short term.
Anyone have feelings on UV Sterilizers for recycled Orc water?

[Ray]

If you have 600+ ppm TDS, that will likely lead to the slow demise of the plants, no matter what the pH. Filtering isn't going to do anything to help that, and if you add any fertilizer or additives, it'll only get worse.

I know of no information related to the efficacy of aquarium UV sterilizers on plant pathogens, especially viruses. Don't forget that they are intended for continual, recirculating use, so don't knock down the count to zero on a single pass, but affect only some at each pass.

If you're serious about growing orchids, you really need to consider an RO unit.

The pH of pure water comes from the carbonic acid formed by the dissolution of carbon dioxide from the air. It is a very weak acid, and should be ignored.


Ray Barkalow
firstrays.com

[ALToronto]

Wow, Tony, your water must be crunchy! What is in the 600 ppm? If it's mostly calcium and magnesium, in a ratio of 3:1 - 6:1, you will be fine growing cattleyas, phals, oncidiums and most slippers. You will not be able to grow orchids that require low calcium water.

How much nitrate is in your water? If more than 10 ppm, you don't need to add fertiliser.