Switching to Semi-Hydro: a repotting pictorial

[pretty_bug01]

How about a idiots guide to semi-hydro. I've read about it in several places, but I am more of a visual person. So could you explain it in detail? All I got out if it is put it in a big pot full of clay pellets, fill with water. But if there are holes in the pot, how is it semi-hydro? How long does it take for the water to come out of the pot? How often to fill it up, how far to fill it up? How long does it take a plant to get accustomed to the switch, and the best time to do that? Basically spell it out like I'm an idiot or something, because I am just not grasping it. Though it does seem to be something I could be interested in.

[Sue]

Jen –

No problem. Unless you mind me calling you "Jen", in which case we already have a problem.

(BTW, we were talking about FAQs for breeding/hybridizing, and this is more a grower's issue. Whether this becomes a FAQ in the general forum is totally up to lja.)


Two ways of doing semi-hydro (S/H): The easy way, and the other easy way.

So first; the easy way. Take a plant which is already potted. Put it in some sort of somewhat deep little saucer or saucer-like object; maybe 1" deep. This way, when you water it, the water collects in the saucer, so it's sitting in water the whole time. Between watering, the water can wick upwards, so not only is the bottom of the pot soaked, but the top stays moist too.

Now the other easy way. Take some sort of plastic bottle. For a classy look, I recommend Gordon's Gin. Drill a hole or two about an inch up on the side. This has the same effect as the saucer above: the area below the drain holes fills with water so it's got some around between waterings.

Either way, you will do well to use extra-tall pots. This allows the plant to grow to a normal depth without having its roots dip down into the reservoir. They probably will anyway, but at least they won't start out in the drink.

So isn't this going to keep the plants really freakin' wet? You bet it will! Do orchids like this? Well, kinda. Roots adjust to their environment by producing different amounts of velamin, and presumably in other ways as well. When you stick a plant in S/H, expect it to take some time to adjust. As to whether it will do better in the long run, after the change has been made . . . well, there are varying accounts. Regardless, be sure to change your watering habits; you won't need to water as often in S/H.

Some orchids don't need to adjust much, if at all, to S/H, because they prefer to stay moist. Even if you don't use S/H for any other ones, do consider it for Phragmipedium hybrids (not species), and for Pleurothallidinae, especially Dracula.

Ah, but we must also discuss media. The most frequently used S/H medium is those expanded clay pellets which are known as Hydroton or LECA. S/H can also be done with perlite, coir, or normal organic media. The nice thing about the Hydroton and perlite is that it won't rot from sitting in water all the time, but I've got Phrag hybrids in peat sphag and bark mixes which are in S/H, and they've been ok so far. I expect to have to repot soon though. If you use fine media like perlite, coir, and/or perlite, fill the pot a little bit higher than the internal or external resevoir with Hydroton, then pot normally on top of this. This will keep the whole thing from being completely soggy, and will help to stop the finer media from being flushed out of the pot, and from clogging the drain holes.

So there you go. Let me know if you have other questions about S/H.

[LJA]

Here is a little guide I just made, step by step, with pictures:

1. Gather your materials.
You will need: an appropriate plastic container, suitable media, a drill, and a plant to repot. For media, we are using fired clay nuggets similar to PrimeAgra. These are roughly 3/4 to 1 inch in all dimensions. Since the principle behind Semi Hydro culture is the same as the principle that rots your orchid's roots when you leave the pot standing in water, choice and size of media is important. As a general rule of thumb, the smaller the media, the finer the porosity, the more water will be wicked up by capillary action and retained. Conversely, the larger the media, the coarser the porosity, the less water will be wicked up and retained. So it's important that you choose a size and type appropriate for the moisture needs of the plant you are growing.

For a container, anything plastic that's deep enough and handy (from the laundry room or kitchen) will do. In this case, we are using one of Brutal Dreamer's favorite pieces of Tupperware I snagged when he wasn't looking, an act for which I'll pay dearly later today:



2. Rinse the media to remove any dust and fines and soak it for several hours. At the end of that time period, water the plant thoroughly.

3. Mark the plastic pot approximately 2 inches up from the bottom and drill holes around the circumference. The holes should be large enough to allow excess water to freely drain, yet small enough to keep the media from spilling out:



4. Drain the water from the soaked media, and pour enough media into your S/H "pot" until it covers the holes. You will need to adjust this initial level dpending on the root length of the plant you intend to repot.

5. WASH YOR HANDS THOROUGHLY WITH SOAP AND WATER, then unpot your plant. This is a Phal. seedling we have been growing in Sphagnum, and the roots are in pretty good shape:



6. Carefully remove the old media from around the roots. Repotting is a "shock" to the plant, so be as careful as possible to keep all of the roots intact:



7. Place the plant into your pot. The plant's lowest leaves should be level with the top of the pot, and its longest roots should not extend below the drainholes you drilled in Step 3. Then, fill the pot to the top with the remaining media, rapping the pot against your workbench every so often to settle the media around the roots. The newly repotted plant should look something like this:



8. Using a dilute fertilizer solution, fill the pot until the liquid runs out of the drainholes.

9. Tada! You're done. Your plant has now been happily repotted into S/H, and you too can now say you're a really cool S/H orchid grower.



Add water / fertilizer solution as necessary to keep the water level even with the bottom of the drain holes. As time goes on, I'll post regular pictorial updates so you can see how this little guy is doing.

[Paphraguy]

lja,

Excellent demo pics and I'm really impressed!

[LJA]

Thanks, Pete! It was a lot of fun doing, and it didn't take much time.

[Heather]

That's awsome! I've always wondered exactly how to do this, but also haven't really delved into it yet since I am so new I figured I should learn to just GROW first...Makes me want to try this sometime!

Nice tupperware. I have a couple of those, but I'd have to steal them from myself! Not as much fun...

[dosal]

One thing - the pot in the pictures shows holes all around. Unless you want to get soaked put holes only in one side. That way you can place the pot on a tray and catch the overflow.

[Brutal_Dreamer]

Oy! That was my coleslaw container! Guess I will have to revert to using the old cool whip bowl for my slaw.

Oh well the orchid is always worth it!

Cheers!
Brutal_Dreamer

[Máire]

Very informative. I'm another visual type. And sorry to hear about your coleslaw container, Dreamer.... lol

Couple of questions...

Once the roots grow down into the reservoir does that mandate promptly repotting into a larger container? I'm wondering what if the roots grow down into the reservoir in the center where you really can't see... Or is it no big deal...?

Also, Sue... you recommended this for Phrag hybrids but not species. Don't many of the Phrag species like to be wet? Or is it a dry/rest issue?

Thanks!
Máire

[Sue]

Originally posted by dosal
One thing - the pot in the pictures shows holes all around. Unless you want to get soaked put holes only in one side. That way you can place the pot on a tray and catch the overflow.

That's exactly what I was going to say!

Originally posted by Máire
Also, Sue... you recommended this for Phrag hybrids but not species. Don't many of the Phrag species like to be wet? Or is it a dry/rest issue?

Don't know much about it myself. That's just something I heard from Peter and Louis. Can one of you guys address this question?

(good to see you around, Máire!)

– Sue.