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"Cacti and Hydroponics: An Unlikely Pair?" · Hydroponics Daily

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  Hello and welcome back to Hydroponics Daily, your go-to podcast for everything soilless cultivation.
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  I'm your host Dr. Russell Sharp and today we're talking about whether you can
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  grow cacti hydroponically.
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  So I'm talking just about cactus, cacti, cactuses, cacti.
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  And I'm not talking about succulents and I'm
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  not talking about those plants that look like cacti but are actually euphobia we're
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  just talking about the cactus family and i thought this would be an interesting
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  one to talk about didn't do any research i allowed chat gpt to randomly talk
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  rubbish had a look on reddit had a look on other sources seeing if anyone's
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  growing cactuses cacti commercially,
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  and basically the answer is yes you can grow cacti hydroponically however nobody's
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  doing it commercially, as far as I'm aware.
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  And those that are doing it, they don't look great. So the answer is yes and no.
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  And I think the main reason for that is obviously that cacti,
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  if they're going to suffer from anything, they're going to suffer from root rot.
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  And that's going to be a big issue in hydroponics. And so that's one big fundamental flaw.
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  But there are a number of people using deep water culture, which is unusual.
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  And the cacti can flourish in that even though they're constantly submerged
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  however you would need to make sure that the oxygen
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  levels are kept very high the nutrient levels
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  are kept fairly low because they're not a high nutrient demanding plant
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  and they're going to grow slowly and that you've got a stable environment and
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  that they're crucially as well that the pathogens are controlled and when you
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  control the pathogens that you don't harm the roots in the process so if you're
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  using things like hydrogen peroxide they can damage the roots make them weaker
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  and even more susceptible to rot if you're not careful.
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  A number of people have looked at the cracky method or the mason jar method.
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  However, I wouldn't recommend this for cacti because the cracky method is like
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  for annual plants or what we term monocarpic, those that die after they've flowered.
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  They use up the water in the cracky pots and then they've flowered and fruited by then.
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  Whereas cacti are perennials and so it doesn't suit itself to cracky method.
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  You could have sort of passive system like an auto pot system
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  cocoa grower you know some people
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  term it hydroponics however it's basically hand watering
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  with hydroponic nutrients it's not recirculatory system that
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  that's probably your halfway house for for cacti
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  the one crop that
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  is actually not ornamental for cacti is a puntier prickly pears and that can
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  be grown with dwc however i if i was going to do a system for cacti and a puntier
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  I would probably do ebb and flood because then or aeroponics but have the flood or the dash of mist.
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  Very infrequent so that then most
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  of the time they're not exposed to water so we've
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  got massive oxygenation so i think apuntia
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  would be a good one to speak to start with apuntia is.
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  The so if you've not seen prickly pear they've got like flat like.
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  Hand like the palm of your hand all your.
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  Fingers together stems and they
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  produce these colorful fruits that are called
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  prickly pears they're not related to pears but they are fairly
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  tasty and they can be sold as a crop and
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  the beauty of apuntia is that they are very resistant
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  to root rots and to environmental
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  stresses compared to normal cacti
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  or other cacti and so
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  you could potentially there's a couple of potential reasons why apuntia
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  wouldn't do well in hydroponics either in a grass house or
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  a grow room that's because they can tolerate much higher temperatures
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  and so you can really
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  increase the light levels they'd be good in urban environments
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  because they're very tolerant of ozone and they
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  absorb the co2 when the lights
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  are off and so you could look at and there
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  might be a co2 enrichment system that is only available at
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  certain times of the day and you could just flood the
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  plants at that time when the lights are off because they have
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  something called cam metabolism or cam photosynthesis
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  which stands for crassulaic acid metabolism they
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  basically absorb carbon dioxide into a acid at night and then convert that acid
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  into sugars in the daytime when there's photosynthesis so there could be some
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  funky things you could do around co2 enrichment you don't want to be giving
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  them co2 during the day when the lights are on because they can't absorb it as well.
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  Other things you need to consider is that when you take cuttings they're called
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  heel cuttings and they need to dry and form a callus for several days to seal
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  them before the roots will form.
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  Sort of substrates you might want to use expanded clay would
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  be my choice to go with first for an
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  ebb and flood system pumice would be after that
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  i wouldn't go for perlite because you'd probably get aluminium toxicity early
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  on obviously water levels and ec controllers
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  ph would have to be really on point and aeration
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  using air stones if you're using dwc even
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  if you're not even if you're using ebb and flood your reservoir needs to be kept aerated
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  and if you're keeping it aerated you have to control microbial growth
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  in it so that's something to consider lights you could
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  do led but you could also do sodium because these plants are going to tolerate
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  much higher light levels and the
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  ph you don't need to they're not extreme they're not ericaceous they
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  don't like acidic or alkaline they will tolerate slightly
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  alkaline levels because of certain species because of where they grow some species
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  of cacti do like a slightly higher ph but they'll they'll all be happy at 5.5
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  to 6.5 and then you'll get some cacti that live in extreme conditions whether
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  you might need colder temperatures if they're an alpine species the hairy ones from south america,
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  and then there is one species that produces normal leaves and looks like a normal
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  plant and you can use that for grafting and what's the name of that one let
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  me just stop there parescia and you can use parescia as a rootstock so you could graft on.
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  Plants that are very sensitive to root rot onto your parescua rootstock potentially
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  if they are compatible and you could do some funky things around that as well so yeah,
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  As I said, the pitfalls of the water and the root rot, they're going to be the
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  first thing that probably kills you.
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  And the disease that comes in after that, I'd start off with a puntia if I was going to grow cacti.
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  They could be good. The reason why you would want to overcome all those challenges
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  is that you would get a lot of kudos, you get a lot of publicity from growing cacti hydroponically.
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  And there might be good research options around that.
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  There could be interesting biochemicals in the cacti. and
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  you could sell them as ornamental plants if you could get fast production
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  of a plant that normally grows very very slowly then you
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  could outgrow your competition so hydroponic
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  cacti cultivation is not commercial at the moment but
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  it could be and it could be a massive
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  opportunity for anyone who's looking to set up a
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  commercial hydroponic system forget leafy greens with
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  low margins high value cactus in Norway
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  or Finland or something like that could be
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  the next frontier in hydroponics someone will try and copy you
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  as quickly as you can set up a commercial one but
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  because there are good challenges
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  in your way you can overcome these with
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  novel and interesting and smart ways then you
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  can stop other people you can put a barrier a moat around
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  your business and that's what you know all good investors are always looking
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  for moats around businesses so something to think about one for the future hydroponic
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  cacti yeah let me know if you've tried it let me know if you failed or succeeded
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  that's been hydroponics daily for today thank you very much for listening.