Aquaponics - Bottomless cup transplanting method

I've had an idea.

I've decided to go with plastic cups as pots for my NFT tubes and strawberry towers. They cost four cents each, and are food safe. Or at least I can reasonable expect them to be food safe.

I drill holes into the bottom of a stack of ten cups at a time so they are quick to modify, and fit the NFT holes well.

But that's not the idea.

It turns out that you can get pretty good growth with more than one plant in even a tiny plastic cup. There is always enough nutrient getting to the plants because there is so much of it around. The problem is, it's a bit tricky to plant two or three seedlings into a little pot. I tried holding the plants with two hands then adding the grow media with a third, but didn't get far with that plan.

So then I tried this...

I cut the bottom out of a cup, and sat it lightly inside another cup with holes drilled into the bottom that would end up being the pot.

This allowed me to sit my three seedlings in place, and at just the right height, being supported by the bottomless cup.

Then I can add my media to the bottomless cup without burying the plants, and I also get to keep keep the roots down where they should be.

Once the bottomless cup is filled to the desired height you gently lift it out, leaving the media behind.

A gentle and rapid transplant that handles the plants as little as possible.

But I wont be using it, because I plan on planting seeds directly into the media.

• My 8 pots at a time will be planted with seeds in individual cups.
• These will be placed into a partially buried empty 2L ice cream container with holes drilled in the bottom in the main grow bed. They will be packed tightly together and taking up a small amount of space.
• Once large enough they will be transferred in their same pots into the original small NFT tube with holes very close together.
• When they outgrow their small homes, they will be moved into the main NFT tubes. 
• Eventually I'll add another 4 tubes of 10 holes each to the growhouse, and another icecream container seed raising bank to the grow bed. That will give 90+ (I think) in total, plus the main original grow bed.

 All with a foot print of 1.8 metres square.

NFT test

[Edit from the future - there is some additional material on NFT ]

As usual, this is one of those things that I just made in the hope that research wasn't necessary until I had failed at least once. I really don't know things like how much nutrient rich water to flow through, exactly how deep the water should be, and, well, everything else. What I do know is that you cut some holes in PVC pipes, stick plants into the holes, and pump water through the pipes.

So I started with what I know.

I cut some holes in some pipe. This will be for seed raising so I'll cut the holes close together.

I'm hoping to be able to move plants around at will to maximise the growing space I have.

If I can move plants, I can grow them densely when they are little, move them to the medium density area when required, and then to the largest spaced holes for a while before harvest.

The plan is for small plastic pots to sit so that they touch the bottom.

And a trickle of nutrient rich water will pass through the base of each plastic pot.

Because I'm still using my sad old pump, I'm a bit limited as to how much flow I can offer the NFT pipe, so I'm stating with a only a broken stream from a 4mm (external) pipe. Basically at the rate of a dripping tap.

Next I added a 90 degree bend, and a short extension with an end cap. This should allow me to adjust the depth by slightly rolling the entire pipe and bend, so that the outlet pipe sets the desired water level.

I was going to make it so that the end cap could be rotated and thus the exit pipe's height adjusted, but it was a better option to seal everything properly (I used plumbing tape for this because I might want to pull it all apart if it doesn't work), and just rotate the entire unit to adjust water depth.


Here's a hot tip I discovered.

Its possible to make a really good seal with clear plastic hose, by drilling a hole that is a bit too small to pass the pipe through.

Cut a slice off an end to make it taper to a point.














Pass it through the hole.

Then grip it with pliers and pull like mad.

With a bit of effort (the more effort required, the better the seal) you can get a very good seal.

Simply pull it all the way through until there is the desired amount of tail on the end inside.

This will be the drain hole, and emergency overflow in case of blockage.




Having said that, clear plastic tube isn't very good for aquaponics, it gets a build up of algae on the inside, and will eventually block. This is just a test, so I want everything to be removable, and I also want to be able to see water draining, but in the final version, I will use black poly pipe.

So my final product looks like this.

Water enters through the 4mm pipe to the end on the left out of frame, and runs through until it drains back into the fish tank, through the elbow, and the clear plastic tubes.

If all goes well.

Now I can pull my new strawberry seedlings from the blue barrel, and add them to the NFT pipes without disturbing them.

This top down view shows the thin black pipe that delivers water just jammed into the hole on the side of the pot, but it will eventually have its own entry hole drilled right at the very end of the pipe.

The seedlings are already showing roots peaking through the bottom of the pots, so they should be just right for transplanting into the shallow water.


In the dirt world, you would have to transplant into ever bigger pots, but I'm hoping that in aquaponics, there will be no need, as the pot really just becomes a convenient handle to move the plants around with, and less to do with how much access to nutrient they have.

Who knows. I'll let you know more as I find it out.

[Edit from the future - there is some additional material on NFT ]