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Clint

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Orchid growers are starting to use passive hydroponics. It's my understanding that all orchid growers do is use a pot with drainage holes about one inch up the side instead of on the bottom. They fill it with ceramic pebbles and water so that there's a reservoir in the bottom. I would have thought that the roots would rot in the bottom in all that water, but apparently they don't. I don't know *why* they don't rot when sitting in an inch of water, unless I'm missing something.

Anyway, why couldn't this work excellently for Nepenthes? You could use pure perlite or a mix of perlite and ceramic and even limestone or other "exotic" ingredients if your species calls for it. The fact that there's water in the bottom presents a problem (or maybe it doesn't since, for some reason, orchids don't mind and I would have thought they'd be the first plants to rot). Why couldn't you add something impenetrable to roots yet also wicks water up to place in the reservoir? Like that green floral foam, or a dense sponge or something?

The advantage is that you water less frequently, there's maximum oxygen to the roots, and the media is never too wet or dry. Of course there are a few species who prefer it a little drier/more wet, but for the majority of plants, maybe even Cephalotus and Heliamphora (Why not?) I think it would work if we could figure out how to address the reservoir. For some plants that don't mind wet feet, the reservoir wouldn't be a problem. The media is also reusable and won't break down and it's said that this method of growing really increases ambient humidity over normal media. For a media that looks nicer and doesn't float, you could use APS.
 
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I use semi-hydroponics for growing D. binata, and it works well. I use plastic half-gallon and gallon bottles that snack foods come in, and drill a couple of small holes an inch or two from the bottom. Then I put a layer of perlite in the bottom of the bottle, so that the top of the layer is just over the holes. If the holes are larger than the perlite, I glue a bit of fiberglass window screening material over the holes before putting in the perlite. I then add a mixture of peat and perlite up to near the top of the bottle, where the D. binata is planted. I usually add a top dressing of LFS, but that is not necessary. I use this method because the water tray method breeds mosquitoes. I adapted this method from semi-hydroponic orchid growing. The reason that I've seen given that roots will grow in water is that roots develop different physical characteristics when grown out of water, so when they are placed in water they rot. When grown in water, roots adapt to growing in the water.
 

JB_OrchidGuy

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Clint it is called semi-hydro in the orchid world. the roots adapt to being in the water because they grow there. The roots the plant had prior to being planted rot. the new ones are adapted to growing there. You have to water often with this system I have found. Not everything likes it. Some thigns it is still too dry. Also if you use the irregular shaped pellets you get a better wicking action over the round ones.

I am planning on true hydro with some weed nepenthes. They will get watered about every 2 hrs for an hr with a pump set to a timer.

BTW this has been around for years. Since before I started growing orchids. It is not anything new.
 
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I have rooted Nepenthes cuttings in a cloning machine and it worked great, they grew much faster than the nepenthes rooted in LFS. I was told that the success rate is much higher for nepenthes that are hard to root too. The only problem i ran into was deciding on what nutrients to put in the water.
 

Clint

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Not new to orchids maybe, but I don't know anyone who's done this. Semi Hygro! I don't know why I keep calling it passive.
 

seedjar

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I've made posts about doing this a half a dozen times, Clint. It works really well. Like... REALLY well. I haven't tried pure inorganic mix but I don't see why it wouldn't work. Orchid mix and LFS on top of a layer of perlite is what I had when I decided to try, and it seems well-received. I use $2 10" aquatic plant baskets for containers because they're the biggest I could find, but I'd like to get some of those nursery pots for orchids with perforations down the sides. Putting them in trays as tall as the pots seems to make evaporation managable. Try it.
~Joe
 

Knuckles

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My rafflesianas roots usually find their way out of their pots and into their water-filled trays. There hasnt been any rotting and they grow just fine. Time to repot though
 
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The term semi hydroponics is not so far away from the hydroponics system. Actually it is the combination of both the old farming system and the new hydro system. Here few features are of the old traditional farming also continue.
 
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