Recirculating water table for phrag culture

[xiphius]

I decided to start the new year off by realizing an idea that I have been sitting on for quite some time. With the move to a new (larger) growing space, I now finally have the room (and the time) to do this - a recirculating water table for my phrags! This idea is based off something I saw on the Gore Orchid Conservatory site years ago (http://goreorchids.com/CatalogAndInfo/Phrag-culture-SH.html). A lot of people grow their phrags (very successfully) standing in water trays. The idea here is to have a constantly recirculcating layer of water from a reservoir, some of the advantages being:

1) constant water level (since the water level is dependant on the reservoir and not on tray evaporation).
2) water stays cleaner (moving water doesn't get nasty nearly as fast as stagnant water).
3) much larger volume of water doesn't accumulate minerals as fast and doesn't need to be changed out as often. So, less maintenance.

I am all about things that automate/lower maintenance so I have more time to actually appreciate and enjoy my plants. Ok, lets get building!

I picked up a shallow, long, and narrow storage tub to use as the base. I am using flexible vinyl tubing for all the plumbing since this will make it easier to take apart for cleaning and also make it easier to shift and move as necessary (flexible). I will attach the tubing to the tub using barb fittings. But first, I needed a way to attach the barb fitting to the the tub! Looking around online and in various hardware stores, I was taken-aback by how expensive PVC bulkhead fittings are ($10-$20/fitting depending on the size)! However, it turns out they are actually quite easy to make from some very inexpensively obtained parts. All you need to make them is a pair of male/female thread-slip CONDUIT* adapters in whatever size you want and an o-ring of the appropriate size. The adapters are about $0.50-$0.70 depending on size. The o-rings I made out of some spare rubber I had laying around. For this particular build, the inlet hose is going to be 3/4 in. ID and the passive overflow is going to be 1 in. I arrived at these sizes since the pump I am using is rated at ~350 gallons per hour for a 2 foot lift. The one inch outlet should easily be able to drain at this rate and keep up with the flow.

Step one (move everybody off the phrag shelf and test the tub for fit):

Everybody off!

Adjust the shelf so the tub is centered:

Step two (make and install the bulkhead fittings):

Adapters:

Pieces - I am joining the slip components using a small piece of appropriately sized PVC pipe. I also cut off the long (slip) end of the female adapter since this will not be required and makes the whole build more compact.

Finished bulkheds - forgot to take pictures of making the gaskets, but I assume everyone knows how to cut a circle

Installing: Cut holes just slightly larger than the threads on the male adapter and popped them in.

Step three (the test):

I put the tubing on and it was a bit stiffer than I expected, so I will probably go ahead and throw some elbows on there to help route the tubing more easily. Works pretty well though! The static water line sits right above the 1-inch overflow. Because the side of the tub was curved near the bottom, I had to drill the hole for this about 1-1.5 in above the bottom of the tub. So the water is a bit deep (covers about 2/3 of the pots). So I may have to put a tray in there to raise them up a bit. If I had been able to find a tub with straight sides, I could have drilled the hole much lower and avoided this bit.

I am going to see about adding elbows this afternoon to get it permanently in place and running.

I can't say I am disappointed in this build. The deeper than anticipated water is an easily fixed issue and a better problem to have then not being deep enough. The whole thing only cost me about $45 ($15 for the tub and ~$30 in sundry plumbing stuff). The pump I had laying around already for aquarium stuff, but these can be bought for around $20. So with the pump, the total build cost is around $65. The reservoir I am using is an old cat-litter bucket that holds around 5 gallons.

Hopefully my phrags find this a great way to start out the new year!

*Note: It is very important to get CONDUIT adapters (in the electrical section) rather than getting PLUMBING adapters. Although they superficially look very similar, plumbing adapters have tapered threads which don't allow you to screw them together completely so the surfaces touch. Conduit adapters have straight threads and you can easily screw them together completely to get a good seal.

 

[Paphluvr]

The concept sounds good and the set-up looks good. The only thing I question is the 350 g/hr pump. That's close to 1 g/sec meaning a total water change every 4-5 sec. Wouldn't you want to create more of a water seep flow rate, maybe in the g/min range? Regardless, I like your idea and hope you'll keep us updated on the results or observations. Good luck!

 

[Linus_Cello]

Supposedly this is the best way to grow PK.

 

[orchid527]

Very clever with respect to the bulkhead fittings. Please keep us updated about how this works for you in the months ahead. The phrags drying out in my greenhouse limit how long I can be away on vacation. A setup like this could take care of the problem. Mike

 

[xiphius]

The only thing I question is the 350 g/hr pump. That's close to 1 g/sec meaning a total water change every 4-5 sec.

It's actually around 350 gal/hr = ~0.1 gal/sec (I think you missed a decimal somewhere in there). The total system volume is around 12-15 gallons, which means my turnover is around 20-25 times per hour. This is actually about the recommended bare minimum for any home aquarium setup. While the water current in the tub is definitely strong, it's hardly torrential (think medium - fast stream, not white water rapids ). The plants should definitely be able to take it. I've seen more than a few in situ photos of plants growing happily in or very near much stronger flows (case and point, see this in situ photo of phrag pearcei). And plants like besseae which grow on very steep rocks would frequently be subjected to really fast flowing water as rain runs over/off the rocks.

I actually see the fast(er) current as a plus rather than a minus as it also means that the water flowing by the roots should be pretty well aerated (another plus of moving vs stagnant water).

The only thing I am worried about is the depth. 2/3 of the pot submerged seems a but much, especially if it's on a continuing basis.

I will definitely post updates/progress!

Cheers!

 

[xiphius]

Supposedly this is the best way to grow PK.

This thought had crossed my mind when I was thinking about building the recirculating setup. One day, I hope to add a PK to my collection .

 

[Ray]

I think it's a great idea, if a bit too deep at the moment, and lowering the drain fitting should be easy.

The one caveat, in my mind, is that if several plants share the bath, you have created the ideal way to share pathogens. I would avoid using chemicals to ameliorate that, so maybe consider an inline UV sterilizer?

 

[abax]

The same thought occurred to me too Ray...also rot in
that much water. My Phrags. would begin rotting almost
immediately with the high humidity in my greenhouse if
I tried that method. In winter I only water maybe twice
a week...if the sun happens to come out.

I do admire do it yourselfers.

 

[Brabantia]

I never very well understand why some growers want cultivate there Phrags with there foots in a tray of water. It seems to me that this is not the best solution to have a good air (oxygène)circulation around the roots.

Envoyé de mon Nexus 9 en utilisant Tapatalk

 

[Ray]

I never very well understand why some growers want cultivate there Phrags with there foots in a tray of water. It seems to me that this is not the best solution to have a good air (oxygène)circulation around the roots

Consider that there are some phrags that grow with their roots growing into streams...

All of my paphs and phrags are doing will in semi-hydroponic culture, in which they are standing in a pot having a 5-6cm water reservoir inside the pot. Each and every plant, over time, will grow its roots right down into the water, with no rotting whatsoever.

I'm not saying that one can just stick a plant into a reservoir, as if you submerge existing roots, they will suffocate and die.

 

[xiphius]

I think it's a great idea, if a bit too deep at the moment, and lowering the drain fitting should be easy.

The one caveat, in my mind, is that if several plants share the bath, you have created the ideal way to share pathogens. I would avoid using chemicals to ameliorate that, so maybe consider an inline UV sterilizer?

I wish I could just drill the hole lower, but the side of the tub is curved near the bottom. So for now I am just going to put a tray in there to raise the pots up a bit and keep the water level the same as it is now (about 1.5 inches). In future, if I can find a tub with straight sides all the way to the bottom that is the right shape, I may just swap out the tub.

An inline UV sterilizer might be a good idea. I might look into adding one in the future. For now, I am not too concerned about the pathogens issue since my plants already occupy communal trays (for quite some time with no issues so far - of course, that's not to say it won't become an issue in the future). Also, I won't have that many plants in the tub. right now since I don't have terribly many phrags at the moment.

 

[xiphius]

The same thought occurred to me too Ray...also rot in
that much water. My Phrags. would begin rotting almost
immediately with the high humidity in my greenhouse if
I tried that method. In winter I only water maybe twice
a week...if the sun happens to come out.

I do admire do it yourselfers.

Yeah, I am definitely not going to let them sit that deep. They probably would rot. I am going to put in a tray to raise them up in the water such that only the bottom 1.5 inches of pot are submerged (which is about what they have currently).

I wish I had high(er) humidity, still adjusting to the new space and this is something I have been struggling with... keeping it above 50% has been a real struggle, especially with how cold it's been outside here

 

[xiphius]

I never very well understand why some growers want cultivate there Phrags with there foots in a tray of water. It seems to me that this is not the best solution to have a good air (oxygène)circulation around the roots.

Envoyé de mon Nexus 9 en utilisant Tapatalk

If you have super-high humidity (like 80-100%) and water a few times a week, then you probably don't need the trays to grow them well. But if your humidity is low or your water isn't terrific, then the trays really help!

Personally, it would be next to impossible for me to grow phrags at all WITHOUT trays of water. They would just dry out too fast and I would have to water continuously. Also, as Ray noted, mine have been sitting in water for as long as I've had them and many are now growing roots out the bottom of the pot completely submerged in water 24/7. These roots are really healthy and in no way rotting or struggling.

 

[xiphius]

Also, as a quick update, the hardware store was out of 3/4 inch right elbows yesterday, so I am going to have to look elsewhere today and temporarily delay the permanent install. But updates with the final installation will be forthcoming!

 

[Ray]

I wish I could just drill the hole lower, but the side of the tub is curved near the bottom. So for now I am just going to put a tray in there to raise the pots up a bit and keep the water level the same as it is now (about 1.5 inches). In future, if I can find a tub with straight sides all the way to the bottom that is the right shape, I may just swap out the tub.

Or...

Drill a hole in the bottom, and use a bulkhead fitting to create a shallow standpipe

 

[littlefrog]

Put a clay saucer or two upside down under each pot to lift them...

And if you are worried about oxygen, get an air pump and bubbler. I bought one that is probably over-oxygenating my 1000 gallon storage tank. I run it 24 hours a day. I think the whole setup cost around $60 at the hydroponics store.

 

[Tom499]

Great to see someone trying this, thank you for the detailed post. I really want to do this one day when I have the space.

I see that the air stone has already been suggested, I couldn't tell if you were using a pump, or also a filter too? My plan is to use my external aquarium filter, as well as a heater to maintain water temps to help with root growth.

I also was thinking to put the pump on a timer, similar to the flood and drain hydroponics systems, so the plants do get a period not submerged.

(With phrags requiring only light ferts, I would then be tempted to go one further and introduce aquatic plants, maybe some small fish... )

 

[xiphius]

Or... Drill a hole in the bottom, and use a bulkhead fitting to create a shallow standpipe

That's a great idea! I had actually thought about drilling the bottom and just putting on a smaller drain when I was setting it up, but the only tub of correct dimensions I could find doesn't have a very flat bottom (it has these weird ridges every inch or so (probably for support so they can get away with using thinner/cheaper plastic). I have already decided that I am going to be rebuilding the tub portion at some point in the future though (the tub by itself is pretty cheap) and I love the standpipe idea. This would let me actually interchange standpipes of different depths (very easily) if I wanted to have slightly wetter or dryer conditions depending on the season.

Put a clay saucer or two upside down under each pot to lift them...

And if you are worried about oxygen, get an air pump and bubbler. I bought one that is probably over-oxygenating my 1000 gallon storage tank. I run it 24 hours a day. I think the whole setup cost around $60 at the hydroponics store.

That's the plan. I don't think I want to put an airstone in the actual reservoir itself, though. This would create the risk of the pump sucking up air bubbles (which is really bad for the pump). But I may throw one in the tray with the plants.

Great to see someone trying this, thank you for the detailed post. I really want to do this one day when I have the space.

I see that the air stone has already been suggested, I couldn't tell if you were using a pump, or also a filter too? My plan is to use my external aquarium filter, as well as a heater to maintain water temps to help with root growth.

I also was thinking to put the pump on a timer, similar to the flood and drain hydroponics systems, so the plants do get a period not submerged.

(With phrags requiring only light ferts, I would then be tempted to go one further and introduce aquatic plants, maybe some small fish... )

I wish you the best of luck when you try it yourself. The build was actually much easier than I anticipated once I found out how to do the bulkhead fittings. I am not terribly worried about the air issue. Right now my plants sit in about 1.5 inches of stagnant water with no problem and have lots of roots growing into the water. They aren't going to be any deeper in the current system (once I adjust the height) than they already are, so it shouldn't be a problem. I may add an airstone to the tub, but I am hesitant to add one to the reservoir as I don't want my pump sucking up air bubbles. I do have an aquarium heater which I plan to throw into the reservoir at least during winter to head off water temperature issues when I have top off the system. Don't want to suddenly shock them with ice water!

The flood/drain idea is really interesting! In theory, you could use a deep tub and this strategy to effectively auto-water your phrags by having the pots completely submerged for 30 min-1 hour per day and then just let the system drain by shutting off the pump. A neat idea that I might steal when adding more tubs for other stuff later on :evil:.

It's funny that you mention fish. When I was done building it, my dad jokingly suggested that we throw in a couple zebra-fish to complete the whole "jungle stream" ambiance :rollhappy:.


I finally found the fittings I needed on the way into work this morning, so I am hoping to get it installed this afternoon.

 

[TyroneGenade]

Thanks for posting your design, and the commentary by everyone else. As I dream about growing Disa again this type of information will go a long way towards turning my dreaming into a plan.

 

[dodidoki]

I tried it once in the past. Fist reply was rotting within few days. Remember a pic of delenatii in situ took by Mr. Cahn. Roots were always wet by dripping water but on the surface of rocks so they could breathe.