Latest / Hydroponics Daily / Compost Teas

Transcript

Compost Teas · Hydroponics Daily

• 0:00
  Hi, welcome back to Hydroponics Daily with me, Dr Russell Sharp.
• 0:03
  Today I'm talking about compost teas, and these are not teas you would drink.
• 0:09
  Even though the British love to drink tea, compost tea is something I would
• 0:14
  very much not recommend to be drinking.
• 0:17
  And that is because these are teas that are made out of all sorts of biological extracts.
• 0:23
  Often there's no compost involved. When we think of compost,
• 0:27
  it's sort of food waste that's put into a big bin, a barrel or a crate,
• 0:32
  and then it's slowly decomposed over time into what we call compost.
• 0:38
  And it's used as a soil amendment, sometimes as a growing media,
• 0:43
  but not a great growing media.
• 0:45
  But in compost teas, you don't really use that material, not that I'm aware of.
• 0:51
  Really what you're doing is you're you're taking things like humic and fulvic acids seaweed.
• 0:58
  Molasses maybe a bit of yucca extract as a wetting agent and
• 1:01
  you're adding bacteria so you might add you might
• 1:04
  add a bit of compost to get to get the the bacteria as the
• 1:07
  source of source of the bacteria or you
• 1:10
  might add a starter culture of a known bacteria that's
• 1:13
  certainly what i would do if i was trying to
• 1:16
  start a compost tea and you maybe maybe
• 1:19
  add it to a tote as you say in america or an IBC as
• 1:23
  we say elsewhere and you can agitate it
• 1:26
  you can aerate it you can heat it but there
• 1:29
  are people doing compost teas that do some of
• 1:32
  these things and none of these things so some people aerate their compost teas
• 1:35
  some people don't some people agitate them some people don't some people heat
• 1:38
  them some people don't some people cover them up and some people don't it depends
• 1:43
  on the actual method and then you just allow it to brew either aerobically or
• 1:48
  anaerobically and then when it's ready,
• 1:50
  when you deem it to be ready you spray it onto your crops and it's thought that it helps with.
• 1:56
  Nutrient absorption, if you're applying a micronutrient at the same time.
• 1:59
  Protection against pests and diseases is a big one. And protection against environmental
• 2:03
  stresses, such as ozone and UV light and things like that.
• 2:09
  So I've seen it used to great effect on ornamental growers, especially in Belgium.
• 2:15
  I've seen compost tea being used a lot there.
• 2:18
  I i would not advise it on fresh
• 2:22
  produce or any food crop unless it
• 2:25
  was very far away from the time of harvest and
• 2:28
  that's because you just don't know what bacteria could be
• 2:31
  growing in that it's not like growing in a
• 2:34
  big fermenter in say a brewery or a biotechnology
• 2:38
  company these are uncontrolled then they're
• 2:41
  not aseptic techniques they are they're not
• 2:44
  going to be sterile and so you could get all sorts of bacteria growing
• 2:47
  in there you could get you know crazy things like anthrax legionnaires clostridium
• 2:53
  e coli so i wouldn't be putting i wouldn't be mixing up a brew spraying it on
• 2:59
  my tomatoes and then eating my tomatoes i've even known non-sterile microbial.
• 3:07
  Commercial products i used to work for a company
• 3:10
  that had non-sterile commercial bacterial products that made
• 3:13
  some some sort of like compost tea type products and they
• 3:16
  had all sorts of things they had bacteria that normally found in like the nether
• 3:21
  regions of your body that would turn up in the analysis so it was pretty disgusting
• 3:28
  that's because the water was contaminated from a sewage pipe hopefully i'm not
• 3:32
  involved with that company anymore they no longer exist.
• 3:35
  Some other disadvantages of compost teas are that
• 3:38
  if you are growing the bacteria the microbes
• 3:41
  up and you get filamentous fungi or
• 3:44
  filamentous bacteria in there then they are too big
• 3:47
  to go through a spray nozzle normally it's
• 3:50
  around 150 to 200 microns micrometers
• 3:53
  that is the limit for a
• 3:56
  spray nozzle and so these filamentous bacteria and
• 3:59
  microbes and fungi can can can block
• 4:02
  these spray nozzles so that's something you have to be aware of
• 4:05
  and also your seaweed and your
• 4:07
  molasses and your hemic acids and your other
• 4:11
  sources of food for the bacteria they may be
• 4:14
  completely soluble when you add them but they
• 4:17
  might react with each other and they might react and convert
• 4:20
  over time by the bacteria into films that block spray nozzles so you always
• 4:25
  have to be careful with that especially this is an issue for many of my farmers
• 4:30
  my regenerative farming customers because they go out and spray 7,000 litre tanks over farmers'
• 4:38
  fields and they block massive spray booms in doing so when they've been using compost teas.
• 4:44
  So that's something to be aware of. When you create biofilms,
• 4:48
  when you get more than one bacteria.
• 4:50
  Going together they can form biofilms but then that
• 4:53
  is also an advantage of compost teas
• 4:56
  is that rather than using a single bacteria use
• 4:59
  a consortium you can get additional benefits they can
• 5:02
  become greater than the sum of their parts and that's
• 5:05
  because of something called corum sensing and that's
• 5:08
  where you get what's called a plank when bacteria are
• 5:11
  just one species on their own floating around in a liquid that's called
• 5:14
  planktonic and the genes the phenotypes the
• 5:18
  genes expressed that produce the phenotypes in those
• 5:21
  bacteria are very different to when they are
• 5:24
  grouped together with lots of bacteria and certainly other bacteria
• 5:27
  and other fungi and then they get something called
• 5:30
  quorum sensing they sense they're in a quorum they
• 5:33
  sense they're in a group and they turn on specialized genes
• 5:36
  because of that and so you can get additional benefits of
• 5:39
  a bacteria that wouldn't normally have that benefit if it was on its
• 5:42
  own so quorum sensing could be a
• 5:45
  major advantage of compost teas and it could be why it could
• 5:48
  be the reason why the proponents of compost
• 5:50
  teas love them and the people who
• 5:54
  denigrate them don't understand why they work so it's certainly not something
• 5:59
  i would denigrate i would certainly look at it if it was an ornamental grower
• 6:03
  i wouldn't look at it if it was growing microgreens or you know something that's
• 6:07
  going to be harvested very very soon if you've got a different opinion let me
• 6:11
  know that's been Hydroponics Daily for today, fairly short one.
• 6:14
  Compost teas. Let's have some compost
• 6:17
  coffee. Has anyone made a compost coffee? If you have, let me know.
• 6:20
  But don't add any milk. I don't think milk would go well in a compost tea.
• 6:24
  I think it would get pretty smelly pretty quickly. A lot of lactic acid bacteria
• 6:28
  form in yogurt and cheese, and that would block some filters.