S/H variation in pond setting

[Jonna]

I've read the excellent articles on SH at First Ray to get an idea of what it is. I want to try a slightly different approach but I think it is similar enough to work.

I have an indoor pond with concrete boxes on the wall above it, water from the pond is pumped up through those boxes from the bottom and over the front back into the pond. The boxes will have no soil but several types of media to hold the bacteria necessary to change ammonia (fish poop) to Nitrites and then Nitrates. There will be some plants bare root in the box, probably several types of fern that will take up the Nitrate. It's a basic bog type filter for a fish pond. The roots of the plants in the box are constantly washed with this fish fertilizer and many plants grow exceedingly well in this.

The top several inches of the media are above the water flow and can either dry out or, if a wicking media is used, stay damp at all times. These top area seems to fulfill many of the requirements of SH and I would like to put some orchids, unmounted, in that area.

I have to pick orchids that prefer the type of lighting available, all natural from an opening in the roof about 15' above that gets light all day but very filtered except from about 11am to 1pm. Even in those 2 hours it is not direct as there is screening above. So, it's medium bright and filtered light.

Humidity is fairly high all year, rarely below 60% and usually higher. Temps also are warm to hot with lows in the mid 60f and highs in the mid 90f, and the water should stay around 78f to 80f perhaps dropping to 75f at times. PH is a little high, it will probably end up between 7.5 and 7.8 because of the initial PH of the water and residual leeching from the concrete. I will acid treat the concrete before filling the pond, cycling it, and adding fish and plants.

This is in tropical Mexico and I'm not sure I can find the medium suggested at First Ray so I will need to try some other things. What about clay pieces broken into similar sizes? What if I mixed coconut coir or sphagnum moss in with the clay pieces? I'm a little leery of doing that because this top few inches won't be washed by the pond water so algae and fungus could grow if organics were in it. I kind of expect algae to grow no matter what but I don't think it by itself is a problem.

I'm new to orchids, but not growing in ponds, and for this location I'm looking for the type of orchid that grows best and prefers the lowest light. This is equivalent to growing in the lower understory of a jungle environment. Are Phalaenopsis the best choice?

I'd love any discussion on preferable media and/or type of orchid. I think it will be a fun experiment and has a chance of being successful.

[Darknessdancer]

Hello Jonna how's all going?

I've been reading your post, and although I really have no clear idea if your S/H pond set-up could work, I believe it could do it.
In my opinion, if you can provide constant humidity and an adequate oxygenation to the roots of your orchids while in said set-up, they may adapt to it and grow to like it, but I think that the nutritional aspect is also very important, and while i don't know about the adequateness of fish poop as an orchid fertilizer or its nutritional content, IMHO if you plan to use it you should take on account that it is probably a not 100% water-soluble fertilizer (i suppose it always has a solid content that may be undissolved), and it may impair its ability to be wicked on top of the LECA and thus provide adequate nutrition to your plants. Besides, if you consider using a water soluble fertilizer, it may be hazardous to the fish in the pond. Also, i think that using organic media may be a really bad idea since due to the high humidity and nutritionally rich water running through it it may become and excellent source of bacteria, fungi and whatnot. Basically, if you suspect that the fish poop can be nutritionally adequate as a fertilizer and soluble enough to be wicked, i say go for it, i've been in Merida sometimes and the weather is quite humid and adequate for orchid growth so they may be allright.
Finally, i live too in Mexico, and I acquire my S/H media (Hydroton) in Home Depot, its about $150 mxp. for a 10 litres bag (around US$15.00 for 3 gallons of Hydroton).
Hope this helps, take care and let us know how all goes
Dark

[Jkelee]

Hi Jonna!! Can we pretty please see some pics of your FAB pond??!!

[Jonna]

Hey, I'd about given up and figured it wasn't an interesting idea or so stupid no one wanted to tell me.

I'm happy to hear you got the S/H media at Home Depot in Mexico. I was at one here the other day looking to see what they have, I didn't see that but now I know the name of it I can ask.

I think using the Hydroton on the top of the bog boxes will help with wicking and keeping the roots out of the actual water. If they grow into it, then fine but I think I'll let them make the decision.

My house isn't finished yet, so no plants or water in the pond. I have a recent picture of the indoor pond though.


The water level will be close to the top, about the same level as the hall floor. The boxes will overflow but without a lot of force either a dribble or a slow sheeting back into the pond. At least, that's how I anticipate it. I can control how much water from the pump goes to the boxes so I will play with the amount until I find a sweet spot - no splashing and enough time in the boxes to filter the water.

I took this pic around noon the other day, I removed obstacles up above so I have more light now. It's open to the sky but there is a fine mesh net overhead and that reduces the light some and breaks up the rain. (it also keeps out the bats and mosquitoes) All of the plants in the box and on the wall will get some rain as well. Air circulation is very good in that hallway and there are also ceiling fans.

I have several areas that I want to grow different orchids, outside under trees and on an east facing wall. All of those will have much brighter light. This wall inside is the one I am most interested in now though. I have to plan one place at a time or I'll be overwhelmed. We're maybe a month or so from finishing, painting should start in another week. After the paint cures I can start putting water in the pond and cycling it.

Fish poop is mainly liquid, I've never seen it stay solid in the pond for long. If it did, the filter before the pump would probably hold it long enough for it to dissolve.

My understanding of how this type of filtering works is that the fish poop contains ammonia, there are bacteria that convert that to Nitrite and others that convert the Nitrite to Nitrate. It's the plants job to take up the Nitrates and release oxygen. Oxygen also comes from the water falling and I may add an air stone as well. The plants will also take up oxygen at night so to keep both fish and plants healthy the water has to be well oxygenated. I've mainly learned this from the fish's water quality point of view, using plants to remove Nitrates from the water.

What I don't know is what other nutrients are added to the water besides the Nitrogen. I've grown a lot of plants in these filters, gingers, aroids, iris, canna and even hibiscus, all bare root. That's in addition to water plants, most of those take a lot more sun than this will have so I need to focus on shade loving plants. In other ponds, I've used tomato stakes near the roots to add more general nutrients for the plants. They are safe for fish. I could also spray the orchid roots every week or so with a liquid fert that was non toxic.

I may put some bromeliads up on the wall or the tops of the pillars where there is much more light. The house is over a hundred years old and this has been a major renovation but I have tried to retain the colonial look. It's been a fascinating project.

[neb]

This is a great idea. You may have unfore seen problems, but I would be suprised if you couldn't make it work and work well.