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

[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?

[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.

[Ray]

Originally Posted by karrolhk

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?

In a 4.5" pot (quart or liter food container), I put two, 1/4" holes in the sidewall about 1"-1.5" above the bottom. They are placed as close together as possible without intersecting. 2 holes because a ball of LECA can block one, but will prevent another from blocking the other hole. No other holes needed or recommended.

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?

No. Just the opposite in fact. "Buildup" requires the loss (evaporation) of the water. Evaporation occurs primarily from the top, so that's where the buildup occurs. If your growing conditions do not favor excessive evaporation and the LECA particles stay moist all the way to the top of the pot, buildup is minimized.

Yes, as water evaporates, the fertilizer concentration in the remaining solution will increase, but that's one reason to fill the pot rapidly to the top at every watering - it flushes and saturates the potting medium, and refreshes the chemistry of the liquid in the reservoir.

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?

That's up to the individual. In my greenhouse or out on my deck, I just let it spill to the ground. For the plants indoors, I have several pots sitting in a large tray that drains to a bucket.

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

See attached

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

No problem at all.

[Mr.Fakename]

Originally Posted by ChrisMalaga

(I'm still shocked when I see her Vandas doing great)

I've been trying pure rockwool and LECA/rockwool mix on Vandaceous for two months or so, and they send more roots than I've ever seen in previous potting mixes.

There's not a lot of info and testimonies of Vanda in S/H, but so far so (very) good.

[Clawhammer]

Originally Posted by Mr.Fakename

I've been trying pure rockwool and LECA/rockwool mix on Vandaceous for two months or so, and they send more roots than I've ever seen in previous potting mixes.

There's not a lot of info and testimonies of Vanda in S/H, but so far so (very) good.

Very interesting! I am experimenting with rockwool and scoria in a s/h container for a few of my catasetinae this year.

I got the rockwool mini-cubes from Ray's website and they are very easy to pot with.