Full vs Semi water culture vs Semi-hydroponics: which is best?

[Ray]

Concerning the temperature, the open, airy nature of the moist LECA medium may lead to a lot of evaporation, depending upon your growing conditions.

Low humidity, high temperatures, and lots of air movement favors evaporation.

If the evaporation rate is high, the evaporative cooling will reduce the temperature of the root zone.

If you are trying to grow plants cooler than your conditions might ordinarily allow, that can be a good thing, allowing you to "stretch" your conditions a bit.

However, if you are trying to grow "hot growing" plants and your conditions are only marginally warm enough, that evaporative cooling might push the root temperature too low, and they will start to fail.

As a general rule, terrestrial plants are much easier to transition to S/H culture than are orchids.

[Orchidtinkerer]

Originally Posted by karrolhk

Btw, I am curious if Ray invented S/H for growing orchids only and then other people applied the same technique in growing other houseplants?

Sorry for so many questions..

Semi-hydro is not used outside of orchid growing. I only use it to raise smaller plants. I don't think it has much use outside the small hobbyist growers. It's great for growing plants that don't have many roots to get new roots established.

Not sure what semi-water culture is

Full water culture as mentioned doesn't get used much and is more of a fun experiment. The reason I don't think it's any good because it does exactly the opposite of what good orchid growing is all about. For me it's making sure the roots can breathe and they cannot breathe in water.

Also another reason why you cannot grow orchids in soil like other house plants - they need more access to air to do gas exchanges and they like to dry periodically. So soil and water are no good long term as they suffocate the gas exchanges causing the roots to die and rot.

Once I realized that orchids need more access to air my orchids started growing better (and ferns too actually - just mentioning it because I've always struggled with ferns till I also let their roots breathe more)

The only main problem that arises as you let roots breathe more is that in order to do so you have to use airier substrate that dries faster so the roots need to be watered more to stop them drying out. It's a bit of a compromise that has to be found between keeping the roots hydrated enough to keep the plant watered and making sure they don't get too waterlogged which reduces their air exchange.

This is one big reason why semi-hydroponics is popular - it provides very airy substrate like lecca. But lecca dries ridiculously fast and nobody wants to keep rewetting the lecca every day..... so it doesn't require much to figure out to just keep a little layer of water in the bottom of the pot to keep the lecca wet. That is all I do. I don't bother drilling no holes or anything I just use clear pots, fill the bottom with water and let the lecca wick the water up and keep the orchid hydrated while very airy at the same time without requiring much watering.

I would also suggest you look into self watering pots for orchids as they are the next step up once your plant has grown a bit bigger, has roots growing down into the reservoir which as I discussed blocks gas exchanges in the roots and once it starts to drink more. People have often found that once a plant outgrows semi-hydro it needs to be watered a lot again so you could stick with semi-hydro I suppose and just keep using bigger pots or switch to self watering pots.
Both use hydroponics in the same way so are equally difficult or easy however you look at it.
I should point out that any hydroponic system is inherently harder for a beginner than a more traditional method like growing in bark.
If you don't know about water ph, what nutrients are in your water supply, what nutrients and in what quantities your orchids needs then you might find hydroponics whether semi hydro, self watering or full water culture harder.
Bark is far more forgiving in that regard, will buffer excess nutrients thus protecting from overfertilization more, will buffer the ph so less attention needs to be given to the exact ph too and some people swear bark has a beneficial effect on root growth.
Far more people will succeed with bark on pure luck than with hydroponic systems.

Hydroponics in my opinion can achieve better results than bark but not everyone will be able to and if you don't get it right in hydroponics than you will end up with worse results than growing in bark. I think that is a very important point to make and I'm not making it to exaggerate or make hydroponics seem hard. But there is a very fine balance betwen getting it right and getting it wrong.
Just like someone playing the violin, if you can play it well it will sounds angelic but only a handful can and the rest sound like screetching noise.

Another point to mention is that a lot of times plants will "sulk" initially getting transplanted from bark or moss to hydroponics. So even if you do know exactly what to do to keep your plants happy they might still go through a long transiton period (I mention long because in plant terms orchids are slower than most other plants) and for most this might not even be worth it.

[SouthPark]

karrol ----- a very experienced grower that has found the right mix of everything (pot type, material, light level, light duration, temperature level, temperature range, humidity, air-flow around leaves and roots and media, watering schedule, fertiliser schedule, mag-cal schedule, pathogen and attacking organism control or avoidance etc) ------ will generally be able to keep their choice of orchids of alive for very long times - like decades, or indefinitely.

Some considerations to be made will include - how many orchids will be in the collection, and whether the system for watering is going to be manual or automatic - which might also apply to temperature and humidity and lighting and air-movement too. So if one needs to manually water the orchids (like I am doing currently) ----- then we have to consider how much time and effort that takes. If we have that time (which I do hehe) ---- then no problem.

Also - consider what kind of orchid is to be grown. so - for some big orchids - or orchids that develop a heap of roots, or may become really big ------ we might have to foresee what's going to happen if we apply a certain kind of method that involves certain kinds of orchid pots.

All the various methods we have today can be workable. It will have to be down to situations and choice - and making sure we know about most of the conditions that can negatively impact the health of orchids - and addressing the conditions.

[karrolhk]

Originally Posted by Orchidtinkerer

Semi-hydro is not used outside of orchid growing. I only use it to raise smaller plants. I don't think it has much use outside the small hobbyist growers. It's great for growing plants that don't have many roots to get new roots established.

Thank you for sharing your experience I would like to follow up on 2 points:

1. By searching "semi hydroponics plants" on Google, I could find many articles about growing houseplants in LECA using the semi-hydro method. That really revolutionize the way of growing plants. That's why I had wondered if Ray's method has been applied in growing houseplants?

2. I am surprised that quite a number of the experienced members here do not seem to think highly of the "water culture" method. I thought it's a good method because I have seen several people on Youtube with success growing orchids using the water culture method. For example, Youtuber "orchid whisperer" grows her orchids by keeping the bottom 1/3 of her roots in water. Others recomend soaking the orchids for an hour and then drain the water (semi-water culture). Here is an example:

[thefish1337]

Semi-hydro is great for growing other plants. Whoever stated that is incorrect. I've grown all types of different plants in semi-hydro setups.

Big reason people are not high on "water culture" is because there isn't a lot of evidence that plants truly "thrive" in water culture. From what I've seen it's mostly phaleanopsis hybrids that people are growing and in my personal experience every plant I've seen should and would look better if it were grown with more appropriate methods. It goes back to the difference between surviving and thriving. If you watch OrchidWhisperer's most recent video her water culture plants are curiously gone or out of sight.

[Orchidtinkerer]

ok well of course in theory semi hydro can be used to grow houseplants, I'd never really seen people do it but I didn't pay too much attention to it either, I have researched whether it has ben used commercially on tomatoes and found that it had not but southpark explains quite well how the bigger the setup the more automated it generally becomes.

Also when looking I did find people mention they had switched other plants to semi-hydro but I also noticed that they aren't actually switching to semi-hydro but in fact to self watering pots.

example: I switched most of my houseplants to semi hydroponics. Here'''s my collection of Hoyas in LECA! : houseplants

A lot of people call both systems the same.

[Ray]

Originally Posted by Orchidtinkerer

Semi-hydro is not used outside of orchid growing.

In my experience, this very far from the truth, but I suppose that depends, to some extent, but how broadly or narrowly you define the technique.

To me, “semi-hydroponics” means the use of an inert medium in contact with a static reservoir of water/nutrient solution to replenish the supply by wicking.

My “big contribution” to S/H was merely the design of the container with a couple of holes in the sidewall to define the reservoir and its use with LECA for orchid growing.

I have seen the technique used for tropical plants in cafeterias in factories throughout Europe. There, the containers were often large, elongated, plastic-lined boxes that acted as room dividers.

When I was first developing the technique, I bought my LECA from a guy whose business was placing and maintaining large tropical plants in offices, car dealerships, etc. - all of which were in the commercially-available “self watering pots”.

I am not a fan of the self-watering pots for orchids, as they are more expensive than a simple converted food storage container, can be overfilled, drowning the roots, and can lull the grower into merely “topping up” the reservoir, rather than pouring solutions through the medium at every watering to flush it. Repeated “top-ups” leads to rapid buildup of minerals and wastes in the medium, which can result in poisoning the plant.

[SouthPark]

In that youtube video ------ at time 7:48 ...... it's mentioned that dry-out time is used in that demonstrated method. It was mentioned in that video the words 'that's when the roots will grow'.

I assumed (and still do) that the 'water-adapted' roots can still grow when they're wet. That's my assumption anyway.

[karrolhk]

Originally Posted by Orchidtinkerer

when looking I did find people mention they had switched other plants to semi-hydro but I also noticed that they aren't actually switching to semi-hydro but in fact to self watering pots.

example: I switched most of my houseplants to semi hydroponics. Here'''s my collection of Hoyas in LECA! : houseplants

A lot of people call both systems the same.

I checked out the link. That person explained his method as "The semi-hydro uses clay pebbles with only few inches of water on the bottom, which allows plenty air flows. ... At the beginning, I showered the plant and change water every 2-3 days. When the plant is adjusted to LECA, I then top up the water when it's dry and only clean pots when it's dirty. Roots is planted on top of the bottom layer of clay pebbles, new water roots will grow down. "

This sounds perfectly semi-hydro to me. How is this not? could you please explain?

[Leafmite]

Someone in my orchid society grows using full hydroponics (air is pumped into the water, nutrients are balanced, etc.--she has a scientific background). She even gave a really amazing talk on how she grows them. Her orchids are amazing and I keep thinking that if I had more room, it might be a fun way to grow my orchids. My orchids are already in basket pots and lava rock.... I was inspired to grow herbs and vegetables in hydroponics.