moving to hydroton

[Ray]

Fast drying is a well-established trait for LECA in traditional culture, but in some cases, that is desirable.

The rate of drying can be affected by the container material (plastic versus clay versus a basket), it's aspect ratio (a wider, squatter profile will dry faster than will a tall, narrow container), temperature, air movement and ambient humidity.

A potential negative of using LECA in traditional culture is that of mineral buildup.

► With organic media components, the decomposition typically outpaces the buildup, so we replace it before toxicity is an issue.

► In Semi-Hydroponics, most of the LECA stays constantly moist, so the salts stay in solution. There is some buildup, but it's slow.

► In traditional culture, where the medium more-or-less dries out completely between waterings, the rate of mineral buildup will be accelerated:

• Upon the first watering, the particles are uniformly saturated with the fertilizer solution throughout.
• As they dry, it is the water at the surface that evaporates first, resulting in an increase in the concentration of dissolved minerals deeper within the particle.
• As evaporation continues, eventually that concentration gets great enough to precipitate the minerals at the core of the particle.
• If you later flush with plain water, it is only the outermost part of that core of deposited minerals that has time to redissolve, and if you water again with fertilizer, the buildup will continue.
• If you use very dilute fertilizer solutions and flush frequently and heavily, you will slow the buildup and extend the time between required replacement of the LECA, but it will take a long soaking treatment to strip it enough for reuse.

[Izzie]

Ray, do you think that applies to fine lava rock used as a medium as well?
If one waters as you suggest, how long before the media would need to be soaked thoroughly? Or could you judge that by looking at the mineral buildup on the surface?

[peeweelovesbooks]

I use 100% hydroton for all my catt alliance plants, and now they are all in clay pots. I fertilize once a week and water when they become dry.

Like s/h, i've noticed that the old roots die off when I make the switch. I don't know if this happens to anyone else though. However, the catts bounce back rather quickly and start making new roots fairly quickly.

[Imperial_Exotics]

I must admit I am quite intrigued by this discussion.

While fishing about the internet, I found orchidarium pics with plants in pots full of Hydroton. Needless to say, I popped right over here to see if I could find some additional info on this and lo and behold, I find this thread.

my local hydro store has setups like this, with sumps and pumps and spray nozzles blasting hydroton etc. Never really looked at it.

Went to the site listed on the first page here, and read the info there. Seems extremely simple, almost too good to be true.

I've got a few hundred Laelia/Cattleya that need potting, this looks like a good time to experiment a bit perhaps.......

[CTB]

Word of caution, lots and lots, and lots of water. I have all my chids in Hydroton. They are all doing great even Phals., which did take longer to adjust.

[Ray]

Originally Posted by Izzie

Ray, do you think that applies to fine lava rock used as a medium as well?
If one waters as you suggest, how long before the media would need to be soaked thoroughly? Or could you judge that by looking at the mineral buildup on the surface?

Izzie, I apologize for just responding. Somehow missed your post a month ago!

Lava rock has a reputation for trapping minerals and building them up at a much greater rate than many other media, and for the difficulty (some say "impossibility") in cleaning it.

[Imperial_Exotics]

Originally Posted by CTB

Word of caution, lots and lots, and lots of water. I have all my chids in Hydroton.

yes.... I am curious about that.

my local hydro store has a continuous spray on the hydroton. With orchids my first thought was they would certainly get root rot.

Obviously this is not the case if people are doing it........

[RosieC]

I don't know about a constant spray but the Semi-Hydroponic technique of Ray's has the media constantly wet, using a resevoir of water at the bottom. It's not the same as full hydroponic growing, but is related to the 'drench and drain' hydroponic method.

Take a look at the info on his site about how it works.
Semi-hydroponics Orchid Plants T5 Lighting

[RosieC]

Forgot to say that one of the key things with the technique is that the roots still get a lot of air as well as the moisture.

Orchid roots enjoy this air/moisture mix provided they were grown that way. You usually expect existing roots to die when plants are transfered to this growing method (although most of mine haven't, not sure why) and so transfer is done when brand new roots are just starting to grow.

[Ray]

Certainly the active pumping of the fertigation liquid to pour from the top would work - probably better than the static hydroponics of S/H culture, however:

1) that is inherently more expensive, what with the need for a special pot, pump, tubing, etc., and
2) I suspect there would be a tendency to attempt to "feed" multiple pots from a single reservoir, and that is the ideal way to spread plant pathogens throughout your collection.