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Hydroponic System Options: Recirculatory vs Run-to-Waste · Hydroponics Daily

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  Hi there growers, welcome back to Hydroponics Daily, your go-to podcast for
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  everything soilless and sustainable.
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  I'm Dr. Russell Sharp, the inventor of gold leaf fertiliser as it's known in
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  the US or liquid gold as it's known in Europe.
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  And today we're diving, doing a deep dive into the world of hydroponic system
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  design or specifically the great debate between recirculatory systems and run-to-waste systems.
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  So whether you're growing leafy greens, tomatoes, rare herbs,
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  medicinal plants, at a commercial scale or an amateur, this will be interesting to you.
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  So what is a recirculatory system?
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  So it's sometimes called a closed loop system and that's where the nutrients solution is reused.
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  So the water that feeds your plants gets collected, filtered and pumped back into the system.
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  So really popular in NFT, nutrient
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  film technique dwc deep
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  water culture and dutch bucket systems with
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  reservoirs or ebb and flood so that's a recirculatory or a closed loop system
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  where everything's recirculated back goes back into a tank gets cleaned the
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  nutrients get might get more nutrients might get added more water might get
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  added the ph might be adjusted might be sterilized and then it goes back to
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  the plants again and again and again.
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  On the other hand a run-to-waste system or an open loop system does exactly what it sounds like.
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  The nutrient-rich water is delivered to the plants and then it's gone.
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  It runs through the root zone once and it either drains away or is collected or disposed of.
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  Sometimes it might be reused for non-edible crops or for landscaping or for
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  gardening but it's only used on your crop once.
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  Now I think you can think of many of the advantages and
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  disadvantages of both systems with me running through them
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  but i'll explain them because there might be some that you've not thought of
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  now for recirculatory systems the big
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  pro is water efficiency so when people talk about
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  hydroponic crops using you know five percent or less of the water of a conventional
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  crop there that assumption is that they're using recirculatory systems that
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  water efficiency goes literally down the toilet down the sewers if you are talking
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  about a runaway system so you can get 80 to 90%.
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  Use less water than a run-to-wake system.
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  You do sometimes dispose of the water. So in a recircularity system,
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  after a while, you might just get a buildup of insoluble salts, algae,
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  or just allelopathic chemicals, chemicals given off by the plants,
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  exudates from the roots, bits of broken root.
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  You might just dump it every now and again just for that.
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  But most of the time, even if you've done that, if it's been through the plants
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  a number of times, then you've been through the system a number of times you're still saving water.
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  Long term it's very cost effective because you reuse your nutrients which means
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  you've got lower fertilizer builds.
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  That's an obvious one but it does rely on everything being completely on point
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  and it's environmentally friendly.
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  Less discharge, fewer pollutants entering the soil and the water system.
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  The disadvantages of a recirculating system are the main one is disease risk.
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  If one plant gets a pathogen recirculates through
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  your system you get a lot of sick plants so all your
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  plants could become sick especially with bacterial diseases or
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  molds and things like this another disadvantage
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  is it's a complex system so you need ph and
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  ec monitoring filtration possibly uv sterilization to
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  keep everything clean that's a disadvantage but it also can
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  be an advantage one of the reasons hydroponic people
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  get into hydroponics is because they like all the
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  bells and whistles all the systems control and
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  things like that so the could be a
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  disadvantage could be an advantage you know when we talk about hydroponics we're
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  normally talking about recirculatory systems true
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  hydroponics another disadvantage is if you don't get it quite right you can
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  get nutrient imbalances so plants uptake different nutrients at different rates
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  over time and your solution can be skewed in favor of one nutrient might build
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  up and one might become depleted so you need to be able to monitor that and you need.
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  Good knowledge of what plant deficiencies look like, you need good monitoring
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  of your pH and your UC, and you need experience in doing that.
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  That won't come overnight, you can't read that in a book, you just need to know how to use it.
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  So run-to-waste systems, they're simpler to manage, don't need constant checking,
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  you just add your nutrients and off you go.
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  You've got cleaner root zones because it's clean nutrients going through every
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  time, you're not going to get any salt build-ups.
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  It's easier for organic hydroponics because many of
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  the organic inputs can clog recirculatory systems just because
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  they often involve suspensions rather than true chemical
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  solutions especially if you're using extracts some
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  of the disadvantages of run to waste is that
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  as the name suggests you've got to dispose of that
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  runoff if you put it down the sewer you're just leading to
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  eutrophication of waterways and and rivers
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  and things like this and even if it goes into soil that's
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  the case you've got higher input costs so you're
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  not recycling your nutrients and the environmental impact without
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  proper drainage management runoff can pollute groundwater as i've said
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  i would always try and if you've got a home hydroponic
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  system i'd always look to put that onto your garden because
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  you're wasting it and you're going to find a useful use
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  for that even if it's on trees or something like that so i
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  would always try and look for run to waste the other advantage of run to waste
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  which is particularly pertinent for gold leaf or liquid gold as it's called
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  in the uk is that you could have an off-grid system because it's a fertilizer
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  that contains every single essential nutrient and that it dechlorinates and it's ph perfect,
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  you don't need to have separate a and b you don't need a computer to control
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  the additions of the fertilizers and you don't need a computer to control the
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  ph adjustment in the in the tank so you could have you wouldn't even need a
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  nutrient tank if you had a run-to-waste system say you had strawberry plants, NFT.
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  Gullies, rockwool, you could literally just feed them through.
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  A water from a ibc or a tote as you call it in north america you could have
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  a dosatron run from a solar solar pump and you could literally just dosatron
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  straight from the from the bottle.
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  Through dilute it into the water and run it through the system and
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  it could all be solar powered with a solar powered pump there's
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  not any of the fertilizer in the world you could do that with
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  and you can get an actual crop off grid so
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  you don't have access to electricity or mains water you could still grow
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  hydroponically and if you're it's a
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  good option if you are a grower who set up a
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  greenhouse and you want to add an additional greenhouse so you might have a computer system
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  in your main greenhouse you could look at this for an easy
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  low-cost way of setting up a grow so you
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  don't need mains water you don't need electricity to
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  run a compute and you don't need a computer system literally just a
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  solar powered pump a dosatron a bottle of gold leaf and
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  away you go and you've got a fertigation solution running
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  at the right optimum into your growing media for your crops and
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  like strawberries or something like that the other advantage of that
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  is that if you don't have a nutrient tank you don't have to
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  worry about issues of precipitation and bacterial build
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  up in the tank and biofilms and algae you just
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  go straight out of a fertilizer bottle really simple all you
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  need to do make sure you shake that bottle every few days to make
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  sure it's nice and homogenous and that's all you need to do so
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  really interesting run-to-waste system and then just make
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  sure you dispose of it in an environmentally and sustainable way that's
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  got low environmental impact so there
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  are a number of options there if you're a beginner grower you
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  might look at a runaway system if you're
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  going commercially then you're going to want to have a if you
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  want if you want to really maximize your lower.
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  Your costs and increase your yield dollar.
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  Spent then you're going to look at a recirculatory system so
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  that's what i would look at if pro tip if you.
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  Are going to do a recirculatory system which we're setting up in our grow room
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  now always make sure you have a good inline filter we're going to have a uv
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  sterilizer we bought a uv filter sterilizer off ebay that was designed for aquarium
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  tanks i but i don't think it's particularly good because,
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  The algae still builds up even when it's been through it. So the planktonic
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  algae that floats. So we're definitely going to invest in a better UV filter.
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  Those filters, they're two pieces of gear that save your crop,
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  save your sanity, and protect you against pythium and algal blooms.
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  So definitely pythium is a disease that is a mold that builds up in water butts.
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  You collect rainwater and pythium you need to be careful of. So UV will control that.
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  So hopefully you've learned something about recirculatory systems or closed-loop systems.
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  And run-to-way systems and just if
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  you are using a run-to-way system make sure that you are doing
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  it in a way that's environmentally friendly does it
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  does break my heart when i see reports of like northern california humboldt
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  county of people disposing of fertilizer in just
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  the redwood forests and things like this just loads of fertilizer
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  bottles building up it's it's one of
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  the most beautiful places in the world and just to have loads of fertilizer poison
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  in it is a real shame so don't
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  do that if you're in northern california if you're anywhere don't
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  dispose of your fertilizer in an environment and environments if anyway most
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  fertilizer bottles are recyclable and um and
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  if you are going to dispose of fertilizer there's always going to be a farmer
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  who will want a bit of fertilizer if you've if you've if you've got excess running
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  around hydroponic fertilizer is the best fertilizer you can get because of the
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  because it costs the most and the best ingredients so if you if you do need
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  to dispose of any fertilizer ever just just speak to a grower,
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  a hydroponic grower, a fellow hydroponic grower, a horticultural nursery, a farmer.
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  I'm sure they would take that off your hands rather than just putting it into landfill.
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  So that's been Hydroponic Daily for today. Until tomorrow, thank you much for
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  listening. If you found value in it, please share it with your fellow growers.
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  And if a fellow grower shared this episode with you, then you owe them a beer.
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  So take them down the pub. Thank you very much for listening. Goodbye.