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Hydroponic Avocado Revolution: Mexico’s Soil-less Orchards · Hydroponics Daily

• 0:00
  Hello there and welcome back to Hydroponics Daily, your go-to podcast for everything.
• 0:05
  Soil-less cultivation.
• 0:06
  I am your host, Dr. Russell Sharp from Utrema Limited.
• 0:09
  We make interesting fertilisers, novel biostimulants and organic biopesticides.
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  And tonight I am sat in front of a roaring fire, so you might hear that crackling away.
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  Tonight I wanted to talk about, or today, avocado cultivation.
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  We talked about the researchers in Norway who were looking at growing avocados
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  in Norway to help with food security and because they eat a colossal amount
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  of avocados in Norway, being a very rich country and having taco Fridays,
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  which apparently is a big thing in Norway.
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  But I've come across reports that hydroponics is being used increasingly in
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  Mexico to grow avocados.
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  And when we think of avocados, we normally think of production in Mexico.
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  So we're going to look at why they are switching to hydroponic cultivation and
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  a few quirky points about growing avocados, which you might not have heard about.
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  A bit of bro science in there and then a stick around to the end because I found
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  a very silly but funny AI tool that I've been playing around with and I'm going
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  to drop some content in there as well.
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  So stay tuned. So, avocados in Mexico, hydroponically.
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  The avocado is native to Mexico, to south central.
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  Makes it sound like it's part of LA there, doesn't it? Dating back 9,000 to
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  10,000 years, the fruit was domesticated by various Mesoamerican groups by about 5,000 BC.
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  So it is endemic to Mexico, which means that it only grows in Mexico naturally.
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  And so, yeah, that's a good thing and a bad thing from cultivation in Mexico.
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  It means the environment must be perfect for it, but it
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  also means that all the pests and diseases that evolved with
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  it are still there so as we
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  know hydroponics has got well established in vegetables
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  and some berry crops but there is
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  a movement to hydroponic cultivation there
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  are a few growers who are growing it in shade tunnels
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  and net tunnels and they're growing the what's essentially
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  trees in there they're using air pots
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  and i think they're using cocoa so an air
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  pot system it's a you know it's an expensive crop so you can invest
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  in things like that in the
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  uk when i've grown avocados in a greenhouse even
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  a heated greenhouse i you have used a pot in pot
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  system which is almost like giving it double glazed
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  glass it gives you a bit of insulation in there to extremes of temperature so
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  that's a good one to use they're using a lot of sensors there's a large greenhouse
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  there's almost like you know the large blueberry or raspberry growers so think
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  lots of netted tunnels like you would in raspberries or blueberries.
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  What i term mypex i think that's a trade name basically
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  that um plastic sheeting down and
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  then either the air pots or the the the
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  the bags that the netted bags holding
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  the the cocoa grow media and then
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  drip irrigation going into every single plant and
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  so just like you would in any other crop then that's fed
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  with a diluted solution of fertilizer so
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  that's really interesting obviously this is a multi-year
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  perennial crop as well so that comes with its own challenges now obviously with
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  avocados you've got to keep them frost free and ideal temperatures of 15 to
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  29 degrees celsius so that is very warm and dry winds cold strong dry winds
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  is what it's particularly sensitive to.
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  There is the haas variety which you will come
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  across that will actually tolerate mild frosts believe
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  it or not but young trees are extremely vulnerable and
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  that's one of the things i haven't talked about when it comes to cold stress is when
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  it comes to perennials the younger plants are always more
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  sensitive okay it does need a
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  well-drained grow media probably why they're using air pots and so they hate
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  to have their feet wet very few plants like to have their feet wet even wasabi
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  and willows don't like stagnant water and the ph is 6 to 6.5 so really in the sweet spot
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  sort of pH you would get if you were using gold leaf in the US or liquid gold in the UK.
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  The problem is that people probably
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  apply too much water when it comes to avocados, keep them too wet.
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  They like to be moist but never saturated, just like other hydroponic crops
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  when they're grown in soil and cocoa.
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  Frequent light irrigation is better than deep soaking, but depends if you're
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  going for a complete hydroponic system or semi-hydroponics with cocoa.
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  And then if you do get root rot, it's probably Phytophora that's going to be in there.
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  So you're going to need at least six to eight days of full sun and shading will
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  reduce flowering of fruit sets. It's not one of these shrubs that needs a bit of shade.
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  It needs a fair amount of nitrogen. And one of the common deficiencies is zinc deficiency.
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  So making sure you've got the
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  pH correct. And that's interesting that you would go for zinc before iron.
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  And then obviously being a fruit crop, pollination is important.
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  And they have two types, a type A flower and a type B flower.
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  And planting one A type and one B type variety increases the yield.
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  And bees are the main pollinator, so maintaining bee activity is crucial.
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  So if you hadn't took into effect its unusual pollination mechanism, then you could...
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  Coming to issues because it's self-incompatible, just like apples.
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  With apples, you can't just plant one variety. You need a pollinator.
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  And so you might have a Hass with a Pinkerton with a reed, which are type A.
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  So you wouldn't have those together. You'd have one of those,
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  and then you'd have one of Fuerta, Bacon, or Zutano.
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  They're really different names, aren't bacon and fuerto
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  has pinkerton sounds like one's american one's british one's spanish all sorts
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  of crazy names there so yeah you need one of it one of the a's and one of the
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  b's together it only needs to be one plant to get the pollination to overcome
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  that self-incompatibility,
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  the main pest and disease of avocado we talked
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  about it phytophora but it's not phytophora ramorum which
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  is the more common one in the uk it's phytophora cinnamomy
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  cinnamomy thrips as
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  always mites there is boring insects into
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  the stem sunburn and fungal diseases so good drainage and avoid trunk injury
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  to prevent those borers getting in yet the crop requires pruning so light pruning
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  when young to shape them they aren't growing to full size just like apple trees
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  aren't nowadays grown to full size.
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  They're kept small to ensure that you don't have to go up a ladder to harvest them.
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  And so same with here. So very similar to apples in that sense.
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  Dead plant material has to be removed every year and just avoid heavy pruning.
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  And they're spaced around four and a half to nine meters apart,
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  which is 15 to 30 feet. If you're working in old money or American money.
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  And the high-density orchards require pruning and management,
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  so you need a good amount of cheap labor.
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  So probably why it's not done universally in all warm countries.
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  And then avocados, obviously the key thing with avocados is getting them ripe at the right time.
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  Avocados mature on the tree but
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  ripen after picking. And knowing when an avocado is ripe is a real issue.
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  And it's all about controlled environment storage and then ethylene-induced
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  ripening and things like this and making sure... Ooh, there's a car alarm going
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  off outside. Making sure that they are...
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  It's took me off my train of thought, that. Making sure they are ripe but not
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  bruised or overripe at the point harvest is a real art in itself.
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  That's why the distributors earn the money they do.
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  And the Hats variety is usually harvested once the skin begins to darken and
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  the fruit reaches its proper size.
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  So there's the the basics
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  and then i'm going to go into some interesting novel quirky
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  facts about avocado cultivation there is some bro science out there or has been
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  out there in the past saying that avocados are the one species that you don't
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  want to wash the seeds to aid germination you actually want to plant the whole
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  fruit to improve germination well i did an experiment on this about.
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  15 years ago and i planted whole avocados
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  versus um avocado seeds
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  i'd harvested from avocados i'd eaten and got 100
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  germination in the ones that i'd harvested and cleaned
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  and zero germination in the
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  ones where i just planted the whole fruit so that's a
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  load of nonsense so you can ignore that many people
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  outside of mexico in europe and america
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  and other places will try and grow an avocado plant from
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  the avocado seed it's very tempting and you can get
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  the plants to grow and you can get a very big
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  plant and you think you've got the ideal conditions but you've.
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  Got to remember that seed is full of oil it's a
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  massive seed and that can sustain a young
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  plant in sub-optimal conditions for a
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  long time so you might think oh yeah it's green it's
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  growing well but you're living on borrowed time
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  the ability to get it to three foot
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  four foot that's when you know whether you're actually growing it
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  correctly you know there's the toothpick technique there's loads
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  of techniques of growing avocado i'm not going to go into
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  them because they're basic and basically you stick an avocado
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  seed in some water or some grow media it's going
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  to germinate grow so don't overthink it really
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  when it comes to avocados the key is the real skill
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  comes in maintaining that plant and getting it to grow not sticking it next
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  to a radiator in a centrally heated room with no light in the middle of winter
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  is always a good option as well because that will kill any house plant at all
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  so a cool well-lit area in the winter if you are in somewhere like England or
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  Ireland or north of USA south of Canada.
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  The self-incompatibility in avocados is what I mentioned, you need a type A and a type B.
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  That's not due to self-incompatibility genes like it is in apples.
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  It's down to the male and the female parts of the flower maturing at different times of the year.
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  So that's why you need the two different varieties.
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  If you were to match them up somehow, you could grow just one variety,
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  but it's the hermaphrodite flowers
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  but the the anthers the pollen becomes
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  mature a different time to the sigma or becomes
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  receptive and things like that in plants this strategy is
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  known as dichogamy okay while
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  animals is known as sequential hermaphroditism so
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  like um some animals will become male
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  and then will become female or vice versa
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  gardeners or new who are horticulturists who
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  are unsure of this unusual reproductive strategy
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  can often suffer from a lack of success when planting
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  avocado bushes so especially if you've just grown a load
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  of avocado seeds and you're a newbie now
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  for some sad news it was it's thought that the avocado evolved alongside the
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  giant sloth and it was this giant sloth eating avocados that would disperse
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  the seeds around south central Mexico.
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  Unfortunately the giant sloth died out a few millennia ago and so now the avocado
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  plant doesn't have its natural pollinator in its native environment or anywhere
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  because giant sloths don't exist anymore. Sad times.
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  Avocados are what is termed.
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  Basal angiosperm okay so basal angiosperms these are and this is a group of
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  plants that are basically a dumping ground for a set of unrelated plants that
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  botanists struggle to understand how are they related and how they evolved so
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  includes magnolias and magnolia-like plants.
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  Birthworks wild gingers which i'm very
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  interested in laurels avocado nutmeg
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  black pepper but also water lilies and
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  other obscure plants like star anise we talked about
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  we talked about tamiflu and things like that so it's
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  a it's a poorly understood how
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  it evolves and it's it's
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  not beetle pollinated but it's in those mango lid
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  type magnolia type plants so
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  very unusual but very interesting group of
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  plants along with sassafras which i
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  think that's root beer isn't it root beer made from sassafras or
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  similar lots of beverages are certain avocado cultivation
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  if you've grown avocados in like 100
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  true hydroponics not semi-hydroponics so you've
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  grown it in nft or dwc or anything like that ebon
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  flood with an inert media then please get in touch i'd love to know more about
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  how you did it and your success rates the perennial crops are always difficult
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  but one as unusual as avocado i think would be doubly difficult i think lots
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  of people grow avocados hydroponically where they put the seed sort of.
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  Suspend it over the water um and but
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  that's very much the sort of cracky method you soon
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  get algae build up eventually and people move on
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  to soil cultivation or certainly cocoa and compost
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  cultivation after that so that's been hydroponics
• 13:53
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