Aquaponics Shell grit seed raising

It seems like Ive been trying for ages to find a decent method to raise seedlings from seeds.

My preferred method would be to just throw them all over the place and see what happens, but I suspect the clay ball media allows seeds to fall way down into it. Its possible that with the normal vibrations of city life, that the seeds fall all the way down into the water and then sink to the bottom and rot.

One problem with raising seeds in potting mix is that you do a lot of damage to the roots when you wash them before transplanting them into the aquaponics system.

I add shell grit to the system as a pH adjuster. The nitrifying bacteria tend to move the system toward the acid side, and the shell grit brings the pH back into line (approx pH 7.0).

So I figured it might be a good idea to raise my seedlings in shellgrit.

I started with a food container, and drilled a few holes around the base.

Then added the mesh from a stainless steel sieve, and filled it with shell grit.

Shell grit can be bought where ever you might buy chicken feed, as they sell it to people who have chickens. Chickens eat it and it helps make their eggshells strong.

I chose a space close to the water inlet in the growbed to bury it so the water flowing through would have high levels of dissolved oxygen. I figured this might be important as the flow through the tightly packed shell grit would be slow.

I buried it at a depth so the water level just reached the shell grit. The water "wicks" up through the shell grit so it stays moist.

I also added a lid in the form of another food container.











Im not sure if the lid is needed, but a lot of store bought seed raising trays have lids so I thought Id add one. It probably isnt required because Id guess the lids are used to keep the moisture in, but with water always wicking up from the bottom...

Who knows.

I have no idea if this will work, but as always, Ill let you know one way or the other.


120 Things in 20 years - My ribs hurt.

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Aquaponics New growbed

I have a shiny new allotment of auqaponics real estate!

Yay me!

With a huge amount of help from Mrs. 120 Things, we added two submerged sections of 90mm PVC as inlet and outlet drainage media screens.

We also cut holes in the top of one end of the BYAP grow bend to allow water in from the fishtank, and the bottom of the other end to allow a standpipe to be fitted.

Then we fitted the standpipe. Basically a short length of pipe that sets the depth the water will sit at, by draining the growbed from the top of the pipe, out through a hole in the growbed.

Or in normalspeak, a plug with a tube stuck in it.

The result of a lot of picking through the media (clay balls) to remove all the rubbish that comes with buying second hand media, was this very nice looking growbed. (the growbed was second hand as well)

Working with a purpose built growbed with purpose built media is soooo much nicer than working with home made stuff. Im all for tinkering and DIY, but if you just want a garden, this pre-made stuff is great. I have no connection with Backyard Aquaponics other than existing on their forum* (as BullwinkleII), but having bought one of their growbeds (second hand), I feel very comfortable recommending them.

Getting there.


* and winning my pump and some other stuff in one of their photo competitions.

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Thinking Beam me up Scotty

Dear The-President,

Im reasonably sure that the pressure difference between the Enterprise and (statistically speaking), pretty much every planets surface, would result in a lot of sinus pain and some scenes involving explosive snot.

I feel these scenes were conspicuously absent in the filming of the Star Trek franchise during beaming exercises.

I further feel that in the interest of reality, this should be easily rectified.

The absence of snot is the absence of reality...

Boomshanka.




120 Things in 20 years - Its possible that I have a cold.

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Aquaponics New growbed flow control

I few days ago I created and installed all the required bits to control the way water enters and exits my growbed.

All this is probably overkill as a lot of people get away with just dumping water at one end, and draining from the other, but theres a fair chance that at some stage down the track I might try to make this system ultra low energy, so I thought Id design it so the water can move very freely through the browbed, and so it doesnt leave any areas that dont get enough flow. If I go low energy, that might mean low flow, so I designed it to what I think is the best way I could.

The plan is to have the water enter into a submerged pipe at one end of the bed that has a lot of holes in it, and exit via a similar, submerged pipe at the other end. This way the water will enter and exit evenly throughout the width of the growbed ensuring that no corners are left to go stagnant. With high flow, this wouldnt normally be a concern, but I wanted to make sure I had lots of options for the future.

After a bit of experimentation I discovered the quickest and easiest way to make holes in PVC pipe for water flow was with an angle grinder.

Just a normal metal cutting blade does a pretty clean job of cutting a lot of slots in a 90mm PVC pipe.

Just tap it onto the PVC quickly and it works a treat. A one second cut is perfect. Three seconds will burn it.






Slots are a must when using the clay balls for media as if you drilled holes, the balls would block them all.

All sized balls will block all sized holes regardless.

Go with slots.

The end result looks like this and only takes around 5 minutes per meter at most.

I cleaned it up with a little sand paper and added end caps and an elbow.

I cut a hole with a hole saw so that I could add a stand pipe that would go through the elbow, then continue on through the growbed.

Theres no great need to make these joins exact because you want water to seep in all through this bit of kit.

I  found some fittings that for some reason have a tapered thread.

When I got them home, I found that the things they screw into dont, which is kind of strange.








The original idea was to cut a hole through the growbed, and screw the two pieces together from either side to lock the fittings on tight.

Because of the taper, I ended up just making the hole in the growbed really tight, and screwing the fitting in really hard so it cut its own thread into the growbed.

It seems solid enough.

This is what the finished drain looks like. This will drain water from the growbed back to the sump.

A pipe will be fit into the recess at the bottom, so that even though the water enters the drain from the bottom of the growbed, the water will exit the device at a bit lower than the top of the growbed.

I cut a hole with my hole saw into the bottom of the growbed.

This is an oddly scary thing to do.

Shiny new water tight containers dont lend themselves to be holed without causing some distress to the new owner.

I cut the hole slightly smaller than it needed to be, and then hand filed the rest so I could be sure of a very tight fit for the threaded component.

Once coaxed through the hole in the growbed, the standpipe was cut to size, and pressed into place without any glue.

Theres no need to glue it because if it leaks, water wont actually leave the system, and there might come a day when I want to adjust the level, or change the system from constant flood to an auto siphon or something.

The drain assembly looked like this when fitted.

The standpipe runs through the growbed on the left hand side.

The other end was completed in a similar manner, but this time with a central inlet because there was already a hole in that position.

This is where water will enter the system from the fishtank.

And thats it.

The growbed part of the system is complete.

Its worth adding plastic caps top the top of the inlet and outlet media guards to keep the clay balls from getting in when your digging around in the garden.





Like I said, its probably overkill to make the inlet and outlet pipes like I did here, but it should make it just that little bit more efficient.


120 Things In 20 Years isnt above pretending to make a new growbed when really I made it more than a week ago.

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