Aquaponics - modular potting III

I thought I might take this modular garden design just one step further.

If I cut holes in 90mm PVC piping so that at one end they are close together, and then progressively get further apart, it should allow me to grow twice as much stuff in one length of PVC, because the gaps between the holes, only need to be the size of the different sized lettuce as they grow up.

If I plant say 2 lettuce seeds in a pot every few days, I should be able to move the tubes along as they need more space, and as I need to plant another pair of lettuce for continuous supply.

So to start with I plant a lettuce in the space on the left. I wait a few days, move the first pot to the right, put a new empty pot in the first slot, and plant some seeds in it.

If I keep doing this every few days, or once a week, I get a continuous supply of lettuce. Or whatever else.

Anything that grows for a long time, like say chilli plants, I'll put into the main grow bed, but all the smaller fast growing things, I should be able to at least double the number of plants I can keep. And all without having to transplant.

I'm guessing it might take 20 seconds to move 10 lettuce along each week.

I think I've become obsessed with seeing how productive I can make my 5 cubic metres of grow house.


  1. Hey mate,

    Love the blog! I'm planning a very similar system with a double blue barrel grow bed on top of a IBC with a 90mm poly pipe NFT around the outside.

    Anyway I just thought your progressive lettuce idea might come unstuck with the crazy volume of roots that they produce, ie pulling out and replanting could be a messy and painful experience (for the lettuce).


  2. Actually it worked pretty well.

    I think from memory I ended up using different tubes for different spacings, but shifting the plants was never an issue. They were all grown in cups, and the small, and even half sized lettuce don't really have enough root that it was ever a problem. Plastic disposable cups (I reused them) have a nice lip on the rim that worked well when you put them into NFT holes that were just the right size.

    As long as you use clean water that has come out directly from a growbed, the NFT tubes don't get clogged, but if you use water from the fishtank before it's filtered, the roots catch everything that goes past them and the NFT tubes will overflow within a week or so.

    One other thing to watch out for with NFT is the temperature rise. The tubes make a great heat sink, so heat up the water quickly. One run around an IBC is around four metres long, and in my system, half that length saw something like an 8c* rise in water temperature from one end to the other.

    I'm glad you're enjoying the blog.

    Welcome to the obsession and good luck with the system. you'll get lots of help and feedback on design ideas if you join a forum, and drop a plan in front of the members. I'm on a few, but spend most of my aquaponics life on...

    as BullwinkleII. Say hello if you ever find yourself there.

    *Dont quote me on that 8c


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