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

[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.

[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.

[karrolhk]

Originally Posted by Ray

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.

Hi Ray,
May I ask you a few questions about S/H:

1. Are the holes located in the middle and top parts of the pot? there shouldn't be any holes on the bottom because it should be a reservoir, right?

2. Since the bottom is a reservoir with LECA always sitting in a solution full of nutrients, would salts build up in the reservoir in the bottom? And over time, the nutrients or salts in the reservoir would accumulate to an intensity too strong. When this overly strong nutrient-rich solution wicks up, would it burn the roots?

3. You mentioned in an article ("the basics of S/H") on your website that when we water, the water must be filled to the top of the pot first to flush everything out each time. So, should there be a very deep dish outside the pot to catch all the water coming out?

4. Do you have a picture of the S/H pots you use?


I am sorry for so many questions. Really appreciate the opportunity to ask you questions directly. Thank you

[camille1585]

Originally Posted by Orchidtinkerer

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.

As someone who works in a company growing leafy vegetables and herbs on a massive scale in hydroponics, I can tell you that your last statement is false, or at the very least incomplete. Roots that grow into water are adapted for this environment, and water contains enough dissolved oxygen for them to live and develop. The key to this is to keep the dissolved oxygen content at acceptable levels, usually by agitation and cycling the water with pumps. In water culture this can be achieved by renewing the water, and I think a lot of the problems seem with water culture, aside from water temperature, are linked to rate of refreshment which is too low and a DO content which drops too much in water that stagnants too long.

Originally Posted by Orchidtinkerer

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.

I may be wrong because I last used a self watering pot a long time ago, but the principle is the same as S/H, and self watering could be considered a type of S/H, or S/H a type of self watering pot. Both systems depend on wicking to function, and both have reservoirs where the roots can go into. I'm not sure where you are seeing a difference. And in both cases you need to step up a pot size if it happens to outgrow it... If a mature plant in S/H drinks up water fast then the solution is either a deeper reservoir section or more frequent flushing, which is all cases is beneficial. Speaking of that, the lack of flushing in self watering pots seems a bit problematic to me, how do you clean out exudates and fertilizer build up?

[thefish1337]

TeChNiCaLlY everyone growing epiphytic orchids is practicing some form hydroponic culture. Ray Barkalow understood this before most and modified the container and identified the best type of soil-less media to refine the method as well as publishing a lot of high quality information about orchid culture on the web. A big thing that Ray identified within orchids is that plants produce physiologically adapted roots for their environment if you understand this fully and completely then you can make most methods work successfully.

Hydroponic definition:

"Hydroponics[1] is a type of horticulture and a subset of hydroculture, which is a method of growing plants, usually crops, without soil, by using mineral nutrient solutions in an aqueous solvent

[Dusty Ol' Man]

Originally Posted by karrolhk

Hi, I am a newbie. I have read much about what are:
- full water culture
- semi water culture, and
- semi-hydroponics

But, I can't find a discussion about a comparison of the 3 methods. What are the pros and cons of each method? and what is the best for different climates?

I believe the answer to which is the best would be: "it depends". Yeah, but depending on what factors? could somebody pls explain?

I suggest you go to the S/H threads and read up. There is a wealth of information there which may answer your questions as they come up. And welcome to the OB.
http://www.orchidboard.com/community...ponic-culture/

[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.

[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.

[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.

[ChrisMalaga]

To anyone interested in S/H, apart from reading all that essential information his inventor Ray published on his website, I strongly suggest to follow Annabel on YouTube (The Orchid Room), she has been able to grow (almost?) any orchid in S/H (I'm still shocked when I see her Vandas doing great), has some videos showing the different wicking properties of different medias (leca, pumice, scoria, etc.), different ways to mix them and different setups.