Water Holding Gels and Semi Hydro
 

Hi y'all,

So I have LOVED growing in semi-hydro! I have noticed the salt build up at the top of the pots, and I'm going to use the plastic coverings Ray suggested as an evaporation reducing barrier, but I was curious, has anyone tried putting a layer of the water holding gels at the top of the pot?

I love having plants as lab rats (african violets are great lab rats because unlike orchids they are ridiculously easy to propagate) so I'm probably going to try one or two with some water holding gels on the top of the pot.

I was also curious, is there anything (besides Seramis because that is not easily attainable in the U.S. as of right now) that has the same size as LECA but holds more water? I wonder for those plants that need tremendous amounts of water if a little "mulch" of something moisture retentive would be appreciated.

I *think* lava rock holds more water than LECA? I don't remember though.

I don't grow in s/h so maybe this is a dumb suggestion but...why not just use some sphagnum on top? I think that would hold some moisture and still allow good airflow. And it's easy to find.

I've tried spaghnum with mixed results...sometimes it works well, sometimes it decides to rot and attract flies...so I'm looking for something that won't break down :) Also sometimes it will mix in with the LECA pellets and reduce air access to the roots.

The gels when wet are denser than water, and LECA is less dense. Gel particles would quickly work their way to the bottoms of the pots.

On the First Ray's Web site, Ray has a demonstration of water holding capacity of various substances for S/H. Lava rock is not as good as LECA.

Salt buildup on the surface means too-high mineral content of the water, not watering often enough, or not filling, then flushing, the pots when watering.

I have no salt buildup 18 months after putting my first plants into S/H. I use rain or RO water. I add a tiny amount of MSU fertilizer - 22 PPM nitrogen - at almost every watering. I flush with pure water about once a month. Every time I water I fill the pot to the brim, then let it drain. During hot weather I need to water a lot more often than during the winter to keep the roots moist in the LECA.

There are several potential sources of buildup on the top surface. - minerals from your water, minerals from your fertilizer, plant wastes, or manufacturing residues from the LECA itself.

If the buildup looks a bit fuzzy, and is tiny needles, then it's from the LECA, and means you didn't clean it well enough before use.

There are lots of different brands of LECA out there, and each is different in one or more properties from each other. All are more dense than water, and will sink if given enough time to absorb.

The particular lava rock I tested wasn't as good at wicking, but that doesn't mean some aren't.

You could try using Synthic at the top of your pot and/or going down into the pot. It won't deteriorate like sphag will.
I tried this with hydroton LECA and it helped with additional wicking toward the top. Just don't use too much as it could prevent enough air from getting to the roots

Where do you buy that? I did a short internet search but it seemed like there wasn't anyone selling it in the U.S.

I found it on eBay, although I don't see it there anymore. Their website lists the dealers, might be best to contact them: Epiweb