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- Semi-Hydroponic Culture (http://www.orchidboard.com/community/semi-hydroponic-culture/)

- - OK....I am curious (http://www.orchidboard.com/community/semi-hydroponic-culture/979-ok-am-curious.html)

OK....I am curious

I have a question concerning the pots and media.

1) Do the pots have holes in the bottom? How high are the holes on the side of the pot from the bottom of the pot?

2) Has anyone tried using straight lava rock for this?

Wally

No holes in the bottom. You need to contain a reservoir some how. Regular, holes-in-the-bottom pots can be used, but they then have to be placed in an external reservoir.
The holes in the side are typically about 1.5" from the bottom, but there's no "magic" to that height. A deeper reservoir may mean less watering, but it's the top-of-the-reservoir to the top-of-the-medium distance that should be controlled, as that's what controls the overall moistuer level.
I have not been impressed with lava rock as a semi-hydro medium:
1. The irregualr shape packs too tightly, restricting air flow.
2. If you use a coarse enough size, the wicking is not all that good.
3. Lava rock seems to accumulate minerals far more than do decent LECA's, and does not flush well.
4. The coarse, open surface porosity leads to "bridging" water droplets, which does two things:
1. 1. Blocks air flow.
  2. Traps minerals and concentrates them as the medium dries.

Thanks Ray...I know we have some local growers that just use lava rock and I was wondering if it would have fertilzer buildup. Being in Central Florida, I need a media that drains fast and doesn't decay fast.

Wally

I'm giving this S/H a try. I am still a little concerned about the fertilizing program I should be giving the orchid.

I have had good results so far with my fertilizer regimen of MSU formula at 125 ppm, given as the only source of water for the plant. Essentially, any time the reservoir nears empty, I fill the pot completely to the top with fertilizer, then allow it to drain over the sink and I'm done.

My fertilizer is a home made recipie, beer,epsom salt,ammonia, works wonders!
Clay

Hey Ray! tell me these cups with the slots in them can be made by anyone with a heated razor blade Right. So all we really need is the prime stuff.
Clay

I suggest drilling holes as opposed to melting (fumes) or cutting (sliced fingers), and you don't really need PrimeAgra either.

PrimeAgra is simply a single brand name of LECA medium, and there are plenty of others on the market. What makes PrimeAgra unique is that is it designed & made specifically with horticulture in mind, rather than manufactured as a concrete aggregate and remarketed into horticulture. Because of that, the overall combination of properties - wicking, packing, moisture absorption & release, pore size, distribution & shape - are optimized.

Whether you, individually, need all of that optimization depends upon your growing conditions and watering habits. For example, folks living in the deep south, with all of its humidity, don't have to be as concerned with wicking, as the high humidity decreases the evaporation rate, so the wicking isn't as critical and can "keep up" easier, even in a less-quality medium.

I'd love for everyone to decide they absolutely had to have PrimeAgra, but it jus' ain't so.

Quote:

Originally Posted by bodaciousbonsai

My fertilizer is a home made recipie, beer,epsom salt,ammonia, works wonders!
Clay

Beer, epsom salt and ammonia?! :_(

Now that really does sound interesting. Does it work? I guess I must be a little boringly self-restrained not to do some such adventurous experimentation mysef.
:)

All of the three chemicals are known to have benefit for terrestrial plants, but except for the Epsom Salts, none will be of particular benefit to orchids, as the medium will not retain them long enough for them to become sufficiently usable by the plants.

Ultimately, their use will lead to plant starvation or poor development, as the brew provides essentially none of the minor and trace elements provided by a decent fertilizer.

I have used all of the above for my lawn, but certainly wouldn't recommend the concoction for s/h culture.