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Thread: Kratky Potatoes and Recycling Foam Packaging

  1. #1
    Jack O'wheelie is offline Germinator
    Join Date
    Feb 2019

    Default Kratky Potatoes and Recycling Foam Packaging

    Hello there,

    I'm planning to do an experimental 1st early potato Kratky hydroponic grow.

    Proposed Set Up
    • Build a 4'x3'x8" nutrient tank with 1 hole drilled for net pots per sq foot.
    • Build a 4'x3'x8" box to fit over the tank to hold inert dry medium.

    How it Would Work

    Using a hydro bloom (potash heavy) solution ph 5.7 I'd fill the tank to just below the net pots.

    Then, I'd put 1/2" layer of pre-soaked perlite in the bottom of each net cup, place in the seed potatoe and then fill around the potato with dry perlite making sure the spud is securely held in an upright position.

    I can then place the box over the tank and fill it with the dry inert medium.

    Wait a couple of months and compare yields with my soil grown crop.

    Submit a paper to the RHC get fame and fortune, retire from planet earth and go show Matt Demon how to really grow shite spuds on Mars!

    I know there will be "many a slip betwixt cup and lip".

    Now, what do I propose to use for the inert medium?

    Crushed/cut up foam packaging.

    I've got loads of the stuff of all shapes and sizes. The local landfill won't take it. The council doesn't recycle it and because I don't fly tip, I'm stuck with an ever increasing pile of unsightly useless white crap.

    It will be tedious work to chop the stuff up into small enough bits but once I've done it, I can use the stuff over and over again for similar projects.

    I welcome any comments, feedback or suggestions.


    Nannysally99 likes this.

  2. #2
    veggiechicken's Avatar
    veggiechicken is online now Warning!! Contains Nuts
    Join Date
    May 2006
    Sunshiny South Wales
    Blog Entries


    Hello Jack and welcome to the Vine.
    I hope you don't mind me saying so, but I haven't the foggiest what Kratky means and know nothing about hydroponics either. However, i hope it works for you because anyway of reusing waste materials is worth doing.
    lottie dolly and Nannysally99 like this.
    Make 2019 the Year of Random Seed sowing
    All we are saying is..........Give seeds a chance.

  3. #3
    Jack O'wheelie is offline Germinator
    Join Date
    Feb 2019

    Default Lol

    Kratky is a Passive Deep Water Culture System.

    It's probably the easiest, cheapest and almost foolproof way of growing hydroponically.

    A search for Kratky will reveal all.

    I like it because of the lack of pumps and plumbing.

    You can go off-grid and just let it grow

  4. #4
    Chestnut is online now Tuber
    Join Date
    Sep 2016


    Hi Jack, and welcome.
    I also have no experience of hydroponics, but wondered if the polystyrene bits might be choppable in either a food processor, or one of those mincer gadgets if you have or could borrow one?

    Something like this
    Nannysally99 likes this.

  5. #5
    Jack O'wheelie is offline Germinator
    Join Date
    Feb 2019

    Default Professor Kratky Lecture

    A lecture by the Master...

    Chestnut >wondered if the polystyrene bits might be choppable in either a food processor<

    Give it a go and let me know how you get on.

    I'm going to need a lot of little bits. So a small DIY concrete mixer with a bucket of bricks would be an excellent way to quickly break down large quantities of EXPANDED POLYSTYRENE EPS.

    I don't have a concrete mixer.

    However, I do have various power tools that should do a good job of ripping the stuff up into small pieces.

    The experiment hinges on the Determinate properties of 1st Early spuds and the fact that they don't need banking up.

    I'm confident that the Kratky method (as outlined) will work and the 1st early's are the right kind of spud.

    The big question is whether the EPS bits with be sunlight proof and stop greening of the tuber.

    I do have previous experiments/experience with bucket grow spuds. The details can be found on my website.

    Bright and sunny but very, very cold here in the north of Ireland.
    veggiechicken and Chestnut like this.

  6. #6
    Jack O'wheelie is offline Germinator
    Join Date
    Feb 2019

    Default Running The Numbers

    My original idea was to have a solution depth of 8" or about .22m.

    (1.2 m) x (.9 m) x (.22 m) = 237.6 litres

    Using 3ml of Vitamax Bloom A and B per litre

    237.6 *.003 = 0.7128 litre

    Approximate cost per litre 18

    1ml per litre Calmag

    237.6 * .001 = 0.2376

    Approximate cost per .25 litre 8

    1ml per litre Silicon

    237.6 * .001 = 0.2376

    Approximate cost per .25 litre 8

    Giving an approximate experiment grow cost of 34 for nutrients.

    This is clearly unsustainable.

    I think I can do much better by following Professor Kratky's lead in his Ginger grow example.

    Reduce the water level to .05 litre with a 150mm air space.

    Using the same calculation as above this gives an approximate experiment nutrient grow cost of 8.50 which is much more sustainable. And should provide a good return on investment.

    However. The seed potatoes must have at least 100mm of roots prior to planting in the net pots.

    This could be achieved by using a much smaller grow tank to start with and then transfer to the bigger final tank until cropping.

    Surprising what problems delving into arithmetic can create.

    But they're good problems with workable solutions.

  7. #7
    Jungle Jane's Avatar
    Jungle Jane is offline Early Fruiter
    Join Date
    Feb 2015


    Are you making something similar to this in the link but with a larger container for the potatoes to grow in? There isn’t much space to grow in,early varieties would be the best to use but a risk of them going green,I’d want to put the seed potato about 12 inches deep & covered. Main crop would want to spread too much,more likely go green I think.

  8. #8
    muck lover is offline Tuber
    Join Date
    Feb 2018


    And I thought I was being innovative planning container grow potatoes in my leafmould with blood fish and bone added.
    lottie dolly and Jungle Jane like this.

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