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Lava rock

Discussion in 'Orchid Culture' started by Boytjie, May 24, 2012.

  1. May 24, 2012 #1
    Boytjie

    Boytjie Out hiking Supporting Member

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    Anybody else have positive results using lava rock as the sole medium? I grow exclusively indoors under lights, and have up till now been using a pretty standard mix (mostly CHC, aliflor, charcoal, perlite and/or tree fern) in plastic net pots. Recently I acquired several Laelia species and decided to try putting them in clay pots with small (1/4") lava rock pieces. The difference is remarkable: fat healthy roots with bright green tips, less dead roots, and faster, stronger, sturdier growth. I'm now contemplating transferring some Dendrobium species to this method, but before I do, I was just curious if anyone else maybe had similar experience. These results might be from the lava rock, or the clay pots, or just specific to my growing conditions.

    -Stephen
     
  2. May 24, 2012 #2
    KellyW

    KellyW Orchid wonk Staff Member Supporting Member

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    Stephen, I haven't used lava rock but I use LECA (I think I have the Hydroton). Most of my potted plants are in LECA. I started doing this to minimize the frequency of repotting. With the inorganic medium you only have to repot when you need to divide or up-size the pot. I would never go back to bark or CHC unless a specific plant requires those conditions. For moist loving plants I do still use sphagnum when necessary. The small lava rock (probably black or red cinder?) should hold more water than the LECA but give similar results.
     
  3. May 24, 2012 #3
    Ricardo

    Ricardo Slave of demanding bird

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  4. May 24, 2012 #4
    goods

    goods Well-Known Member Supporting Member

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    I grow all of my non-mounted orchids in lava rock, except a Phrag in semi-hydro and the Pleurothallids in sphagnum. They are mostly made up of Catt. alliance species and hybrids and a Dendrobium or two. Ever since I moved them from traditional media to this, I've seen tremendous root growth and more, stronger, new growths.

    Using this not only has the benefit of not breaking down, but it also allows me to water a bit more often with less of a rot worry. I tend to be a little heavy handed when I water.
     
  5. May 25, 2012 #5
    Uluwehi

    Uluwehi angraecoids, dendrobiums and more Supporting Member

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    I think that there is a medium for every growing environment and watering habit :)

    In Hawai'i I used lava rock (we call them cinders there) for a few orchids but more extensively as a component of potting mixes for non-epiphytic, potted plants. It can be a great component, but unlike horticultural pumice, perlite or LECA, lava rocks (cinders) have pockets in them that sometimes collect and hold water for longer than roots prefer.
     
  6. May 25, 2012 #6
    goods

    goods Well-Known Member Supporting Member

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    Jacob, I agree with your statement about pockets holding a bit too much water. I forgot to mention that I use the larger chunks. These don't ever fit uniformly in the pot, so there are alot of voids of just air. I use mostly clay pots, so I imagine this provides a humid microclimate. This may be one of the reasons I've seen all the root growth with the switch.
     
  7. May 25, 2012 #7
    Boytjie

    Boytjie Out hiking Supporting Member

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    I was also wondering if this could be part of the reason for the great root growth. Roots have been growing much better and healthier in the lava rocked plants in clay pots, as opposed to the ones in plastic. -Stephen
     
  8. May 25, 2012 #8
    mrbreeze

    mrbreeze Anglican Supporting Member

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    I also use a lot of lava rock, usually in clay pots. Overall I've had better luck with it than pretty much any other media and it has numerous advantages.
     
  9. May 25, 2012 #9
    Alexey

    Alexey Well-Known Member Supporting Member

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    To all listed above advantages can add more: summering outdoors in the terra-cotta pot / lava rock semi-hydro setup my Dendrobium nobile-type hybrids can bloom in August (as on this 2008 photo), due to chilling effect of this setup. However, the space in the pot is limited (rock is rigid) and division of the plant is rather traumatic process for the roots.
    Den Red Emperor 01.JPG Den Red Emperor 02.JPG