Are drainage holes needed?

[jetflair]

I'm playing around with semi-hydro. Orchid beginner, working with Trader Joes Phals. They all come rotting in densely packed moss, so I've repotted all in LECA and all are doing visibly better.

My confusion is pot and drainage related. I have some in bonsai pots with bottom train holes, some in net pots, some in net pots with an outer pot as a reservoir, and some in mugs with no drainage. I've used a tray filled with water and put the ones with bottom drainage as well as the net pots in it.

I'm frankly confused about how much air circulation and moisture is needed. I'm seeing everyone do the side holes, but if they are not for air circulation, why do we need them at all? Couldn't I use a glass tumbler and eyeball how much water to leave at the bottom?

Will I harm my plant with the LECA in a mug potting method?

Also, should they be allowed to dry out fully between waterings, or not?

[Ray]

The air flow in and around decent quality LECA pellets is sufficient in any pot. The drainage holes in the side of the pot don't add much to that, but serve to limit the depth of the reservoir, yet allow you to flood the pot when you water, flushing plant wastes and mineral residues out. If you simply "top up" the reservoir, you'll soon poison your plants.

If you grow in LECA and allow it to dry out between waterings, you are not using semi-hydroponics, but are just using traditional culture with an inorganic, inert medium.

Have you read the stuff here:
Semi-Hydroponics


Ray Barkalow
firstrays.com

[jetflair]

Thanks Ray! Yep, I've gone over I think every page of your website And I want to order orchids from you!

I'm one of these very detail oriented people who reads everything and then gets hung up on things like this. So, if I don't have drainage holes, I will be okay but will need to take more time and care flushing?

I've since your first reply repotted the ones in bonsai pots etc. so that there is a reservoir.

How often should I flush them? Every watering?

[Ray]

Originally Posted by jetflair

<snip>So, if I don't have drainage holes, I will be okay but will need to take more time and care flushing?

If you have no drainage, the only way to flush is to invert the pot and dump the contents, which will likely result in dumping the LECA, won't it? I just wouldn't go there.

How often should I flush them? Every watering?

Yes. At every watering.

[mtorchid]

<Also, should they be allowed to dry out fully between waterings, or not?>

Some orchids like to "dry out between waterings", some don't. You've got to know how your container "works" in order to accommodate that. I like to grow Phals in LECA in wood baskets so as to avoid root rot. They thrive in it, but they are watered quite often as they are not true S/H.

<How often should I flush them? Every watering?>

You didn't mention how often you fertilize. You don't want to saturate the roots with water before they can soak up the fertilizer or dilute the fertilizer with a flood of water. I would recommend flushing (with no fertilizer) thoroughly once per month. If you don't, you're not in control of the amount of fertilizer your plants are actually getting.

[Ray]

I have yet to find an orchid that HAS TO dry out between waterings. The controlling factor is the amount of air getting to the roots, rather than the presence of water.

I also have to disagree with Carl's last statement. I have fed my plants at every watering for the last 20 years. I don't get into trouble because 1) I use a very dilute solution, 2) I flood everything heavily when I water, and 3) I try to avoid letting the potting media completely dry out.

[mtorchid]

<<I have yet to find an orchid that HAS TO dry out between waterings>> Ray

They're out there Ray! It's all relative though. Think of roots needing to "dry" between waterings but in a 50-60% RH environment though, not a Death Valley environment.

<< The controlling factor is the amount of air getting to the roots, rather than the presence of water>> Ray

As the higher percentage of water lowers the amount of air available, it's easier to think of as an air/water ratio, not an air vs. water problem.

<<I also have to disagree with Carl's last statement. I flood everything heavily when I water.>> Ray

"Carl"? You mean Marc? You forgot to mention that you have a greenhouse. Flooding every time you water in a house just isn't practical. Better to fertilize weakly/weekly and flood thoroughly monthly, unless you only have a few orchids or don't have anything better to do than go back and forth to the bathtub every time you water.

[daddydoall]

Ray has more experience than anyone with SH, but I agree with Marc. Adopting to SH can be a big setback to some Orchids, and total failure for others. Some of my Cats never adopted, and but I rescued them transfering growing in LECA in Net pots allowing more air and drying out to occur. The lithophilic species / hybrids have not adopted for me. Many "mini" cats which seem ideal for SH are struggling / dying rather than adapting (even though grown warm). I'm sure SH works better in warmer conditions too. In my GH in SF bay area I have half my collection in SH and still consider in an experiment since it has yet to prove superior to traditional culture for me. LECA in Net pots with a shallow tray is a compromise that seems to work well as the tray keeps the LECA damp, lots of air flow, and the water evaporates quickly so they still dry out almost every day.
Dave

[mtorchid]

Dave, that's interesting about your Catts not doing so well in SH, everyone's growing area is different. Mine do quite well in SH. It's my Phals that needed to be transferred into LECA as traditional medium. They thrive in wooden "vanda baskets", LECA and some Sphag on top to help retain a little moisture. I also set them into clear plastic trays (about 3" - 4" deep) which provides a higher RH micro climate.

[fotofashion]

IF you grow your plants in an outer decorative pot w/o drain holes and have them outside, you will have to drain the water out every time it rains. That is a regular pain because, as Ray noted, you have to upend the pot every time with resulting loss of LECA. I happened to buy a couple of plants from a grower who sells them in LECA in an inner pot with a gauge to show how much water is in the outer pot. That is OK if you grow indoors, but outdoors that's rot waiting to happen. I just removed the plants from the outer pot a day or so ago.
Beverly A.