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"Greenhouse Material Guide: Choosing the Best for Soilless Cultivation" · Hydroponics Daily

• 0:00
  Hello and welcome back to Hydroponics Daily, your go-to podcast for everything soilless cultivation.
• 0:06
  Now when we think of hydroponics, many people will think of indoor growing,
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  so growing in a grow tent, a grow room, or even a warehouse.
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  But hydroponics also covers polytunnels, it can cover outdoors,
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  and it can also cover greenhouses or glasshouses.
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  We tend to say glass houses in horticulture
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  even when they are not made of glass so
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  today we're going to talk about choosing the right material for your
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  greenhouse the skin and the skeleton so
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  the skin where we think of that as the glass but
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  could be another option we'll look at optimizing
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  lights longevity cost and
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  also insulation which is often not thought about so the
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  first option is single pane glass standard and
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  low iron options excellent excellent scratch
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  resistance and lifespan they do last a you
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  know decades if you treat them well and they are lucky that
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  they don't get smashed in a weather storm or
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  from your children hitting a
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  football or somebody else is somebody else smashing
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  them they will last a long time they transmit high
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  quality light and with good
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  clarity so around 98 transmission they
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  have better insulation than some of the alternatives however they're not as
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  well insulated as say you're double glazing in your house they have duller hemispheric
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  lights and um cannot be drilled and they're heavy i don't know what hemispheric
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  light is answers on a postcard please for that one.
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  But yeah they can be cleaned though and they can be cleaned with some very aggressive
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  chemicals so traditionally they would use some really nasty acids to clean them
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  and make sure that there was no algae or,
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  dirt build up on them and the transmission could stay at around 98% so that's
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  what they do commercially on big glass houses and now they're starting to use
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  drones to clean them as well so spraying the chemicals on.
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  You could potentially use double paint or even
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  double glazing with a gas filled option for
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  added insulation however that is expensive and you'd really have to be a heavy
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  use of expensive heat to make that worthwhile so that's not if you really want
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  good insulation then you're probably going to use polycarbonate which is the sort of thing that you,
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  you'll see it's got like a looks like a ladder side on
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  it's used in the uk in in conservatory
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  constructions and you can get opaque versions and
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  transparent versions and for a greenhouse you want a transparent
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  version the thing about this one is is it's um it's
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  got good insulation because it traps the
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  air in that twin wall panel it's also impact resistant
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  so if you in an area where you know things are going to hit your greenhouse
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  then you could then you'd struggle to get anything to go through it you know
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  you can walk on this if it's secured in place you're not going to snap in two
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  but it might come away at the seams that's the other thing to consider there's a famous.
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  Story about a executive in a high-rise in new york and he took a load of his kids from his
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  kids his kids go to school and they went on a school trip brought
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  all the kids into this high rise and he was showing them the the
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  skyscraper and he said look this glass is so strong
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  if i ran up and jumped up against it it wouldn't break and
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  he took a big long run up and he jumped up against it and it didn't break and
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  the problem was it came away at the seams and he fell to his death in front
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  of his kids and all their friends so yeah don't jump on a polycarbonate greenhouse
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  because it may give way you see people walking on single pane glass house roofs
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  and that someone scale of heights that does.
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  You know scare me something that i would ever do i have
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  a mixture in my greenhouse of polycarbonate for the roof and
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  glass for the walls and it
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  can be a good option if you if you know you're going to make it opaque so sometimes
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  you put whitewash on onto the glass so that to diffuse the lights if you're
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  going to do that anyway then polycarbonate could be a good option you could
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  just get a diffuse version of that polycarbonate.
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  It comes as standard for the likes of conservatories and side buildings and things like this.
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  So polycarbonate could be a good option there. Also, if you don't want people
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  to see into your greenhouse, rather than putting whitewash on,
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  which washes off over time, you could use an opaque polycarbonate.
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  Well, not opaque, but what's the word I'm looking for?
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  It transmits light, but you can't see through it, whatever that
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  one is frosted frosted that's the word you could also
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  use one-way film on the glass
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  however that's going to absorb a lot of light so you're not going to get anywhere
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  near that transmission you would if you didn't have a filter on it you can use
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  acrylic plastic to uses the skin of a greenhouse however acrylic or is known
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  in the u.s plexiglass and it's lightweight excellent optical clarity,
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  medium insulation, weather resistant, less prone to yellowing the polycarbonate,
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  but modern polycarbonates don't yellow very much.
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  However, it can go on fire. So you've got lights in there, LED lights or sodium
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  lamps, then, you know, you know,
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  you might struggle to get insurance for that. And you might want to consider
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  that your greenhouse could go up in flames.
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  Tends to not be used very often, acrylic really. Cheaper greenhouses tend to
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  use acrylic. So that's something to bear in mind.
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  You can use film or PVC coating, PVC options. So like you would in a polytunnel.
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  Very low cost, very lightweight, very quick to install, but a short lifespan, one to four years.
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  Not durable and they don't filter.
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  Out uv so you might get lower yields
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  but higher value crop they also
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  get a lot of condensation on them so that's considered that drops down
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  in your onto your crop and you can get gray mold now a
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  really good option is like pv
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  film or pvc that's into like bubble wrap
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  like that you would get in packaging now
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  a very very strong version of that is used in
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  the uk a firm called keder k-e-d-e-r
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  keder greenhouses are really strong and because
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  they use this bubble wrap type reinforced bubble wrap type material
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  to make sort of a cross between a
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  polytunnel and a greenhouse they're like really expensive
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  polytunnels they're not cheap but they
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  are very very resistant to mechanical damage
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  so they're used in like the really northern
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  scottish islands like the shetlands and the orkney isles for growing
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  crops up there where you know they can struggle for a lot of the
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  year and their light transmission is not so
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  much of an issue it's more insulation increasing the growing
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  season without having to use heating
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  and things like this expensive heating so cader greenhouses are something you
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  know something that would be on my list of things that i would like to invest
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  in a nice cader greenhouse they're really good for filming things in as well
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  like just like a greenhouse much closer than a polytunnel we've got vertical
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  walls. It's more like a green house.
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  When it comes to the structural material, aluminium is now by far the most common
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  type because it's lightweight and,
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  corrosive resistant, low maintenance and clean. So you don't need to,
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  and you can clean it easily.
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  It's cost effective compared to wood, much easier to handle and assemble.
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  It's got a lower thermal mass, which can be a disadvantage, can amplify internal heating and cold.
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  So any, like if you've got a plastic cladding, then that could degrade when
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  it's close to the aluminium.
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  You could use galvanised steel, it's another option. It's strong and stable,
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  ideal for large commercial structures.
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  So like the really tall greenhouses you can
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  anchor heavy glazing panels without bending
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  however however it is by its nature heavier and prone to rusting without protection
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  you know the galvanized will wear off and more expensive to install the traditional
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  amateur material or even commercial material was cedar wood or redwood in america
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  that was used mainly cedar in the uk.
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  Provides some sort of natural insulation to a bit the
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  reason why it was used is visually appealing a red
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  cedar greenhouse looks great that's what i've got it's easy
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  to work with and diy friendly it's rot resistant
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  red cedar especially if you
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  treat it but that could potentially leak leach chemicals
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  and things like that uh my greenhouse is as old as
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  me it was handed down to me from my
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  father so i've still got the same greenhouse so it does last
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  a long time it doesn't rot however it's has had
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  a few things replaced over the years getting close to the
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  end of its life now you could potentially have plastic or
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  fiberglass greenhouses these would be at the
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  low end low cost options they're corrosion corrosion resistant but they're just
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  less durable they warp and they don't have good structural strength compared
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  to aluminium steel or wood so you know i would probably if i was going for if
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  i'm going to replace my greenhouse i'm probably going to go for a CADA which would be,
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  aluminium poles with a.
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  High-end plastic sort of
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  bubble wrap filter on it if I wasn't going
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  to go for that I'd probably go for an aluminium glass but with
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  coverings on it to prevent the glass from breaking
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  because I've got young kids that's something to consider with glass
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  is that you know they are going to hit footballs and golf
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  balls and cricket balls in my case at the greenhouse and
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  so I have to put a plastic covering over the
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  walls of my greenhouse and have a polycarbonate roof because of that because
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  they don't want glass flying everywhere and obviously it's going to be harmful
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  to the people near and around who get exposed to that glass and also if it goes
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  onto the inside the greenhouse and you you've got potential for contamination
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  of the crop and things like that.
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  So that's something to consider so there's different positives
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  and negatives a lot of people when they start designing their
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  own greenhouse they start to look at acrylic and you'll
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  see people with like making greenhouses out of old
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  doors or old materials and they'll start
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  using acrylic and things like this but they don't last long so really i'd
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  really go for polycarbonate polycarbonate is harder to shape
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  and than acrylic so it's you couldn't
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  it's much more difficult to produce things like triangles or curves
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  than it is in acrylic or glass if you
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  go if you want to cut glass you can normally take them to a hardware store
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  an old an old old school hardware store just phone up and ask them if they cut
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  glass they'll cut it to any shape you want rather than trying to do it at home
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  if you're not an expert in cutting glass then it can be expensive and dangerous
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  so that's my thoughts on glass house materials.
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  You could protect this potential for using films spectral
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  films to increase different light levels
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  that's been used in the past however now with led lights you
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  could just put a tunable light in there to increase the the
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  spectrum of a certain wavelength of light so
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  something there to consider for both commercial and hobby greenhouses
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  i've been dr russell sharp you've been listening to hydroponics daily and if
• 11:29
  you could share this podcast it would mean the world get my listener figures
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  up i've recorded about six of these podcasts this morning because i'm going
• 11:37
  on holiday to holland so hopefully one of the next few podcasts will be about the dutch,
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  flower auctions which i'm hoping to go to because they're
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  right next door to where we are staying so fingers crossed i'll get into one
• 11:48
  of those they're not cheap to go into i think they're about 50 euros so we'll
• 11:53
  see you have to get up really early which i'm not looking forward to either
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  so but you know the early bird gets the worm when it comes to flower auctions
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  so watch this space thank you very much for listening until tomorrow goodbye.