RO water reconstitution - Orchid Board

Epiphile · #1 02-05-2010, 10:48 AM

Hi everyone,

I'm fairly new to all of this, and have a poor understanding of the science involved, so I'm hoping someone can help.

I'm currently using RO reconstituted with MSU fertilizer for pure water. What I'm wondering is whether there's a minimum level of fertilizer I can use, above which I won't see nutrient deficiencies. I realize that different species prefer different nutrient levels, etc. I'm hesitant to shoot for levels optimal for plant growth because some of my plant are kept in vivaria into which I'm hoping to introduce amphibians, and am seeking to find some manner of middle ground between the two. At the moment I'm dosing to a meager 10-20ppm N, and I wonder whether I'm asking for trouble.

Thanks in advance for your thoughts.

Aaron

Ray · #2 02-06-2010, 03:53 PM

Good question, Aaron.

I suspect (guess) that at low dosing rates, you'll simply see a very slow growth rate, as opposed to any out-and-out deficiency. Probably no blooming, either.

Epiphile · #3 02-11-2010, 10:10 AM

That's reassuring, Ray- thanks.

From what I understand there is a danger in using straight RO water as through osmosis nutrients can actually be drawn from the plants by the water, and so I wonder at what minimum level the water can be kept to avoid this. Of course in nature most epiphytic plants would probably never see even 10ppm of nitrogen unless they had collected some detritus around themselves- I tried to look through some studies on water throughfall and stemflow in forests and nitrogen levels rarely reached over 2 or 3 if I recall correctly.

I'm actually still getting some flowers at the levels I'm at now, which is great... probably not as many as I'd see with an increased fertilizer content, though- you're probably right. I am having issues with a few plants, but I guess there are other cultural variables I could be looking at apart from nutrients.

Thanks again, Ray.

Aaron

Leisurely · #4 02-16-2010, 09:44 PM

Several months ago one of our members commented about growing her orchids without the addition of any fertilizer and she claimed that her orchids grew and bloomed just as well as the orchids that she saw of society members who brought in their plants for show. I don't remember what she used for a water source.

I had to leave my orchids in the care of someone for fifteen weeks once. They received no fertilizer during this period and were watered with municipal water. I was amazed at how they had grown when I returned nor did blooming seem to be impaired either.

Epiphile · #5 02-16-2010, 11:53 PM

That's something else as well.

As far as when your collection was being taken care of, do you happen to know anything about the source of the water used? Was it from the tap? It'd be interesting to see what the water report looks like.

calvin_orchidL · #6 02-17-2010, 12:19 AM

Toronto and GTA water in general is very good. I watered for a whole year without any fertilizer and I got no problems. Switched to RO water and had some problems after about 8 months, until I recently started to supplement with fertilizer...still waiting to see if things improve but I think most of the damage has stopped and new growth is coming out nicely.

phearamedusa · #7 02-17-2010, 12:22 AM

Hi Epiphile,
I'm just a short drive down the 401 from you. Have you decided what kind of amphibian you're going to have in the vivarium? They will raise the amount of fertilizer your orchids and other plants receive. Check out some of the vivarium sites like OB sister site Vivarium Forums , or www.dendroboard.com.

I hope this helps. Regards Melanie

Epiphile · #8 02-17-2010, 08:06 AM

Quote:

Originally Posted by calvin_orchidL

Toronto and GTA water in general is very good. I watered for a whole year without any fertilizer and I got no problems. Switched to RO water and had some problems after about 8 months, until I recently started to supplement with fertilizer...still waiting to see if things improve but I think most of the damage has stopped and new growth is coming out nicely.

It's true that our water quality is comparatively good (very low in nitrogen, though, for better or worse). Do you think that you'll see improved growth with your reconstituted RO water? At what levels are you fertilizing?

Quote:

Originally Posted by phearamedusa

Have you decided what kind of amphibian you're going to have in the vivarium? They will raise the amount of fertilizer your orchids and other plants receive.

I'm thinking about starting with Phyllobates terribilis- I believe they will contribute nutrients, but only to a point. My impression is that they spend the majority of their time on the ground. Since most of my plants are growing epiphytically, I would imagine that they won't see any of these nutrients.

I know people have good luck with aged tap water, but past the fact of other dissolved solids, etc. I just want to see if it's possible to push the fertilizer envelope a bit. I've yet to find something that indicates the levels at which different components in fertilizers become problematic for sensitive animals, but I guess that aspect's better addressed in the other forums you mentioned.

Leisurely · #9 02-17-2010, 04:04 PM

Ephphile, the water they used for the entire time I was away was city water. The city provides an analysis yearly but most everything listed says either meets or doesn't meet EPA standards. I do know that dissolved mineral salts are very low; somewhere under 50 ppm.

Reptile · #10 03-16-2010, 01:47 PM

Quote:

Originally Posted by calvin_orchidL

Toronto and GTA water in general is very good.

Sorry, I have to disagree on that one. I live in the GTA and I also have a fish tank, so I did water tests on the tap water. GTA gets the water from lake Ontario and the pH is quite high (8). Not to mention the general hardness, which is very high (I don't have the numbers right now).
It's not what I would use for orchids, since they need a soft, slightly acidic water. That's why I use distilled water supplemented with MSU.