Backyard Aquaponics
A place to discuss aquaponics

I would like your thoughts on my future build of a wicking bed. I am planning on building one to try and id like to not use wood so i thought about using cinder blocks and a pond liner along with the sock type piping at the bottom i am thinking 4x8 bed. Everybody seems to use wood and while that is fine i just dont like the idea of it rotting on the ground all the time.

I just used a little but you could substitute metal for those spots if you wanted. Here's my thread - the bed construction is good and even though the wicking portion works there are better ways to set this up - http://www.backyardaquaponics.com/forum/viewtopic.php?f=18&t=13622. 4 x 8 is a good size and easier to manage if you have to clean one of the beds out to repair a liner.

So what about not using metal and just using cinder blocks for all of it? and based on your comments i wont do gravel as the wick.

I built an experimental WB from a bath tub then used that knowledge to design and (in process) build an IBC x4.
I needed them level so I'm going to elevate them on foundations like my GBs. If I had a flatter site I would have not needed to brace the under side of the IBCs and just set them on packing sand.

Pete.

I have an IBC wicking bed. I'm expanding and did a bunch of research recently on different ways to build a wicking bed. I concluded an IBC cut in half is cost-competitive with a 4x8 bed with either cinder blocks or wood and pond liner and much more resistant to puncture/leaks. Of course, this depends on the availability/cost of IBCs. I can get one for about $100.

I also am going to try self-watering wicking beds, like in this clip:
https://www.youtube.com/watch?v=Spt0hFVLeKk&t=24s

Using a float valve in a bucket to maintain constant level with water from either rain barrels or my AP system.

My thread (link below) has a photo of the wicking bed that I have.

It costs me about 75 bucks for an ibc and about the same for cinder blocks + pond liner. what kind of depth does a WB need to be? and at what level does the various stuff need to be? Thats the part i cant find much info on. I think a IBC would be easier because well... cut it and bam your almost done vs cinder blocks would be heavy and a pain but i think i would rather look at cinder blocks. Does anybody know of anywhere that used them for a WB i cant find anything with it.

>> what kind of depth does a WB need to be?

it depends a bit on the plants being grown and the size of the reservoir you want/need.

I have made a 300mm deep one from IBC (was a grow bed from a 700-300mm chop) and I find that good for pumpkin and beetroot and things that dont mind a bit of moisture. However for other things the full half IBC (about 400mm) is much better IMO. Too shallow a bed is a risk for root crops etc that might rot if it stays too wet.

If you go IBC the trick is to cut them vertical so you get two smooth bottoms without the lid or outlet.
You just leave the middle strip that has the lid and the outlet off.

Minimum *dirt* is around 250mm (10") but many plants like a bit more.
So you really want to end up with around 100mm water and 250mm dirt/organic matter at a minimum.
(12" / foot of dirt/material over a 4" reservoir would be reasonable starting point).

>> but i think i would rather look at cinder blocks. Does anybody know of anywhere that used them for a WB

no but they are used a lot for DWC's and there is no reason why you cannot use them. In fact only the reservoir section needs to be fully waterproofed. Liner will be fine as many variants use that.

There are various ways to make a wicking bed and the short answer is that all basically work.
* the classic is rock gravel at the bottom then shadecloth and then soil etc on top.
* the variant is to put containers and/or pipes into the bottom to increase water storage - these rely on dirt to wick.
Food&Fish has some good blow by blow instructions for these on his thread.>
viewtopic.php?f=18&t=663 pages 146, 158, 166-170
* the third type uses wicking materials within the beds. These are more common for smaller setups and wicking pots.

leave you to do the metric to inches....

[edit] here is a good thread to look at viewtopic.php?f=18&t=12933&start=60 Lot of chat in between but the pics are over pages 2 to 7. You could easily do this style with cinder blocks.....

here is another to look at - IBC setup > viewtopic.php?f=18&t=23402

Gravel is actually more the reservoir, it's the landscape fabric and soil that are really where the wicking comes from in mine but yes I don't suggest using rocks, it's just extra work. I think Milne's (aka Food & Fish) IBC beds just use milk crates and mix for the reservoir and wick respectively but it's been awhile since I looked at them.

The only issue I can think of is figuring out how to get the drain hole incorporated and same for the inflow if you're going to automate filling with a float valve. Your blocks won't be in contact with the soil inside the bed so alkalinity (which might hurt acid loving plants) and any potential for leaching (some worry about this with blocks made with ash from coal processing) should be nonexistent.

Something else to think about if you might get chickens or other digging animals, is whether you have to worry about them getting in the beds and tearing the liner. At least with IBC there's not much chance of that. Good pond liner beats the heck out of thick plastic and is probably good enough as well.

Here's a combination grow bed and wicking bed setup done with the narrow cinder blocks which were installed, lined and finished, came out pretty well - http://www.backyardaquaponics.com/forum/viewtopic.php?f=18&t=24300&start=15

OK so it sounds like I could do 4x8 with cinder block and pond liner and then have a small bit of wood or tin or something to stick the overflow through then the sock with some sand covering it then a shade cloth then 1ft of dirt and I think I'll put some bricks on the bottom to keep weeds out or plastic or something. Should I use mortar or anything with the cinder blocks?

Heres an interesting read if you have time
viewtopic.php?f=18&t=12933
Or here if you have plenty of time
viewtopic.php?f=18&t=663&start=2175

>> Should I use mortar or anything with the cinder blocks?

doesn't matter. Mostly it is going to be 3 rows high or so, so you want to make sure it is stable.
I have used blocks like cinder blocks simply by putting them up and putting something inside the internal holes.
That is much quicker than laying and can be taken down easily.

>> bricks on the bottom to keep weeds out or plastic or something.

don't really need to. If using a liner simply throw some clean dirt down and go direct on that.
Maybe some weed matting or old carpet or something.

your bottom water reservoir section need to be waterproof so a liner will be easier than sealing...
Can just stop the liner at the max water depth and it will leak out after that.

relevant pages for both of those F&F mentions above are in my post couple up, save you wading through.

Mk sounds good, so you think a sheet of tin would be strong enough for the space to drill the overflow or what would be good?

your bottom water reservoir section need to be waterproof so a liner will be easier than sealing...
Can just stop the liner at the max water depth and it will leak out after that.

sorry just edited during time your post went up to say this....

you can use a bulkhead if you want to. Wouldn't use tin.
Just get some of the plastic flexboard (corflute etc) or something stiff plastic for the bulkhead to grip onto and just have a gap in the blocks.

What about a bit of a Ibc top cut to fit in the space of a cinder block seems good enough to me.

that works. If using a liner make sure the liner is neatly held by the rubber washer or whatever you use.
as its an overflow you probably don't care so much if it leaks anyway. [not like a DWC or grow bed].