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As some may have noticed in my signature, one of my other hobbies is hydroculture, which is basically passive hydroponics. I have tried growing various carnivorous plants in hydroculture but, perhaps with the exception of Nepenthes, it has not been very successful.

This year I decided that I would try an active hydroponic system on a Dionaea muscipula (VFT). For this experiment I have used a homemade hydroponic system. The growing medium I used is small rockwool cubes (1cm x 1cm x 1cm), with a top dressing of gravel to keep them in place and to make things look a little neater. The base of the VFT bulb and the roots are in the rockwool, therefore the rockwool is the growing medium, not the gravel. This is all contained within a mesh pot, with air line tubing running through the pot to an airstone underneath it. This is then placed into a watertight container and rainwater is added to a level just above the base of the pot. The idea is to get the rockwool wet but not have the roots actually sitting in water at this stage. The other end of the air line tubing is then attached to an air pump which oxygenates the water via the airstone, this runs continuously. I have added a little fulvic acid to the water to acidify things a little but I don't know if this essential, I just had some so I added it. As you can see from the pictures, I've used a clear container, this is perhaps not ideal as light may encourage algae growth, though the rainwater that was added was initially a little green but has cleared. I will keep a close eye on this and cover the container if algae starts to appear. The plant has been in this system for a couple of weeks and it has put on new growth. This is encouraging as I expected the plant to show signs of stress but there has been no evidence of this so far. I will update this post on the progress of this experiment.

Overview of system:
SS851171.JPG


Plant in place:
SS851169.JPG


Rockwool cubes:
SS851178.JPG


Pot containing rockwool cubes:
SS851195.JPG
 

seedjar

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Very interesting. I've been curious about how rockwool would work for CPs for a long time. What were your results like with Nepenthes? I'm looking forward to seeing your results with the VFT - my money is on it working. Do you know if there are any significant root temperature differences with this type of hydroponics vs. traditional methods? Seems like evaporative cooling might play a much bigger role in this system when compared to a typical soil-potted setup.
~Joe
 
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My results with Nepenthes in hydroculture weren't very satisfactory. Although the plants survive, they do not thrive. I think that an active hydroponics system like deep water culture (DWC) or aeroponics might be more successful.

I've not measured the root temperature but I think you are probably correct in that evaporative cooling might come into play.
 

RSS

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I've played around with some Utric's in rockwool a bit and had good results. They were completely passive. I would think any CP's would do well with aeroponics, but I don't have the space to test it out.

Have you tried any of the Ping's that can grow submerged? I would think they could take the "wet" of rockwool.

Another thing to try would be a flood/drain system with some expanded clay pellets. The entire thing could be put on timers. Oh if I only had the space, I have a perfect 18" X 48" drilled tank......

I've used clay pellets with a few CP's with acceptable results.

Are you using any nutrients?
 
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RSS,

Unfortunately, limited space is an issue for me too. The above is the only hydroponics setup that I have at the moment, though I do have a number of plants in hydroculture.

I have not tried nutrients on the VFT and I'm a little wary in doing so as they are typically not exposed to any in nature and I don't want to risk root burn.
 
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Very cool experiment. :D

I'd be interested to see the changes in the water quality and rate of use with this. Are you monitoring pH, TDS, etc? What kind of lighting setup are you using? I'm guessing there isn't a very long outdoor season for VFTs in Scotland... heh.

A thought - one potential difficulty I see might be in repotting. I don't know how long rockwool cubes hold up, so I don't even know if it would ever need to be repotted, but it seems to me that over time it might be difficult to get the tube out easily or something. Adding water would seem to be more of a pain with a hydro system, but it also seems like you'd lose a lot less to evaporation than pots sitting in a tray.

I wonder if dessicated insect bodies getting down into the media would be a problem...

Keep us posted. I'm sure a lot of people who have to grow indoors would be interested in using soil-free setups for their CPs if it's viable.
 

seedjar

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Rockwool more or less never decays. It's stone that's been melted down and extruded into a steel-wool-like lattice. Think really porous concrete. You're guess is probably very correct, though - it will probably be a real pain to repot if the roots start knitting the cubes together.
~Joe
 
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Very cool experiment. :D

I'd be interested to see the changes in the water quality and rate of use with this. Are you monitoring pH, TDS, etc?
I've not been monitoring it but I have the equipment to measure TDS. I wouldn't think that the TDS would change significantly as nothing is being added.

What kind of lighting setup are you using? I'm guessing there isn't a very long outdoor season for VFTs in Scotland... heh.
The sun is my lighting setup :grin: The plant is on a south facing windowsill. Being northerly, we have long daylengths in the summer.

A thought - one potential difficulty I see might be in repotting. I don't know how long rockwool cubes hold up, so I don't even know if it would ever need to be repotted, but it seems to me that over time it might be difficult to get the tube out easily or something.
As per seedjar's reply above, rockwool does not break down significantly. It is in quite a large pot for the size of plant so I don't think it will outgrow it for some time but when it does I will transfer it to a larger pot retaining the rockwool that is not easily removed.

Adding water would seem to be more of a pain with a hydro system, but it also seems like you'd lose a lot less to evaporation than pots sitting in a tray.
It's very easy to top up, just pour the water over the surface of the rockwool and it drains through into the reservoir quickly. At the moment I am having to top up once a week. That will increase when the weather gets hotter. Eventually the roots will probably grow down into the water reservoir so the level will be able to go lower. The frequency can be reduced by using a larger reservoir.
 
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Here's a quick update:

During a two week holiday, in June, the plant in my original post was beset by a little 'accident'. Below is a picture of the replacement plant.

Replacement plant, 29th June:
update_june.jpg


Plant on 6th September:
update_september.JPG

update_september_growing.JPG


October 17th
october_2009.JPG


In August I noticed that growth started to slow down so I decided to add some nutrients. I also added a lightproof sleeve as the nutrients would encourage algae. I finally settled on 5ml/l Orchid Ultra (humic and fulvic acids) and 0.75EC Ionic nutrient solution in deionised water. I have been using this ever since, but now the VFT is going into dormancy so I have reverted to using just deionised water.
 
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Awesome experiment and great results!

For those of us that aren't familiar with hydroponics, could you give me a basic summary of what exactly you have set up there?

Is it basically simply putting a VFT in rockwool in a mesh pot and then topping off with water and fertilizing (skipping the aerator part)?

How often do you fertilize with the 5ml/L of Orchid Ultra?
 
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Hi mmlr38,

The first post details the setup; however, I have summarised below.

  • Pre-soak rockwool cubes in a slightly acidic (5.5 pH) water. I use fulvic acid to acidify deionised water to 5.5 pH. I then rinse with deionised water. This ensures that any alkalinity in the rockwool is fixed.
  • Place a layer of rockwool cubes in the bottom of a mesh (aquatic plant) pot.
  • Suspend VFT in the mesh pot while adding rockwool cubes around the roots, surrounding all sub-surface parts of the plant.
  • Obtain a watertight container (referred to as reservoir hereafter) which is approximately twice as deep, or more, as the mesh pot.
  • Place an airstone in the bottom of the reservoir and run an air line from it, attaching to an air pump, with check valve, at the other end.
  • Suspend the mesh pot into the reservoir.
  • Make up a nutrient solution. I use Growth Technology Ionic nutrients diluted at a rate of 0.75EC in deioinised water. I also add 5ml/litre of Growth Technology Orchid Ultra.
  • Add the nutrient solution to the reservoir, pouring it through the rockwool cubes in the mesh pot. The nutrient solution should be in contact with the layer of rockwool cubes at the bottom of the mesh pot, but no more than that. You don't want the roots of the VFT sitting in the nutrient solution at this point, they may grow into it at a later date but that's ok. The rockwool cubes, in the base of the mesh pot, in contact with the nutrient solution, will deliver it to the VFT roots via capillary action.
  • Switch on the air pump. This will need to run 24/7. If the nutrient solution is not aerated then the roots will probably rot.
  • Keep a regular check on the nutrient solution level and ensure that it is always in contact with the rockwool cubes at the base of the mesh pot. Top up with nutrient solution when necessary.
  • The reservoir will need to lightight or algae will start to grow in the nutrient solution This is bad for various reasons and must be avoided.

Notes:

I dump all the nutrient solution from the reservoir approximately once a month and add fresh.

Orchid Ultra is not a nutrient solution. It is humic and fulvic acid and I add it as VFTs are likely to receive these from the surrounding bogs in their natural environment.

I use a good quality hydroponics nutrient solution. Normal plant food will not be sufficient and may actually be detrimental.

A EC meter is necessary to measure the nutrient solution concentration.
 
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Mmlr38

I think it's just a case of growing plants without soil and getting the plants to take minerals from the water only... I think the air stone helps with oxygen so it does not stagnate... I think that somes up hydroponics, short verison, please correct me if I am wrong.
 
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Mmlr38

I think it's just a case of growing plants without soil and getting the plants to take minerals from the water only... I think the air stone helps with oxygen so it does not stagnate... I think that somes up hydroponics, short verison, please correct me if I am wrong.
Sort of, but the air stone does more than stopping the water from stagnating. Delivering oxygen to the root zone increases nutrient uptake and accelerates growth. See HERE for more details of the method used above,
 

seedjar

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Hey mobile, what type of nutrient solution did you use when you tried Nepenthes? I'm curious to know if this would be a more effective method for rooting cuttings that just stagnant water.
Thanks,
~Joe
 
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Hi seedjar,

I used Growth Technology Formulex for Nepenthes. This is often referred to as a 'soft' nutrient solution and is commonly used for seedlings and cuttings. It has a N-P-K of 1.8:0.21:1.95
 

Not a Number

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From what I've been reading even if you pre-treat the rockwool it acts like a buffer and you have to monitor the pH.

Dionaea appear to need more acidic conditions than most other CP species (BACPS panel of growers). And their roots are more sensitive to nutrients than other species. With a high enough level of nutrients the roots atrophy and plants slowly die over a period of 2-3 months. This fits in with the observation that Dionaea growth gets more stunted the longer they are potted in the same media. An repotting "rejuvenates" growth. Peat moss breaks down with age releasing nutrients. Some growers repot their flytraps as often as once a year.

I wouldn't rely on TDS to monitor pH without taking baselines.
 
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From what I've been reading even if you pre-treat the rockwool it acts like a buffer and you have to monitor the pH.

Dionaea appear to need more acidic conditions than most other CP species (BACPS panel of growers). And their roots are more sensitive to nutrients than other species. With a high enough level of nutrients the roots atrophy and plants slowly die over a period of 2-3 months. This fits in with the observation that Dionaea growth gets more stunted the longer they are potted in the same media. An repotting "rejuvenates" growth. Peat moss breaks down with age releasing nutrients. Some growers repot their flytraps as often as once a year.

I wouldn't rely on TDS to monitor pH without taking baselines.
I agree, pH needs to be monitored. At the moment I can do this with litmus papers but I need to invest in a pH meter in the near future. The main reason I add Orchid Ultra is because it consists on fulvic and humic acids which lower the pH. I've been using 0.75EC nutrient solution for approximately three months now and have not observed any detrimental effects yet. In fact, the roots are starting to appear out of the mesh pot and growing directly in the nutrient solution. My setup is quite basic and would benefit from a larger reservoir which would give more EC and pH stability, but I didn't really anticipate VFT hydroponics actually working so didn't invest much time or money in it. I intend leaving this as a long running experiment and will post results, whether they be positive or negative.
 

seedjar

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Hi seedjar,

I used Growth Technology Formulex for Nepenthes. This is often referred to as a 'soft' nutrient solution and is commonly used for seedlings and cuttings. It has a N-P-K of 1.8:0.21:1.95

Haha, fertilizer specifically for Neps - I would never have thought. I'll search around for that.
Thanks,
~Joe

PS - Oh, now I understand. You were using italics in the context of proper binomial naming. I'm too used to being lazy and using unstyled text - I thought you were trying to emphasize that there's a hydroponic formula for Neps in particular.
 
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Erm may I know why can the Vft take nutrient up it's root without getting sick???
This plant has been in nutrient solution for months with no sign of any problems. I add Osmocote to my standard VFT mix of peat/perlite/sand and again have not noticed any ill effect. Time will tell if there's any long term effects.
 
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