Air Crete vs Concrete For Raised Beds

David Trammel's picture

I'm a big fan of using concrete bricks, specifically what's called "partitioning blocks", which are regular size but half as wide, to make raised beds.

My current raised beds are just one brick high. Given my decline in physical condition, not big but getting down on my hands and knees is getting more and more difficult at 62, I'd like to increase the height of my raised beds when I move in with my sister at retirement so I can weed from a sitting position. A taller bed would also allow me to experiment with soil additives like Hugelkultur.

That's why I found this Youtube video interesting.

The Complete Guide to Air Crete Raised Garden Bed

If you know anything about the Romans and concrete, you know that they often added volcanic pumice to the mix to lighten the weight of their structures and bricks. Air crete does the same thing, but with organic material like hay or straw.

Larger blocks, especially ones that have an inter locking mechanism, and which I could bond together, might be the way to go. Not sure if I'd save any money, the partitioning blocks if I remember are under two bucks a piece but might be better even if more costly.

Has anyone worked with lighter versions of concrete or poured your own

Blueberry's picture

IMHO stay with the blocks easy to work with and you can stack then up 3 high and just use rebar to hold them in place. Just drive the rebar in the ground about 2 feet a number 5 rod should be ok. In my part of the world concrete cost $110.00 a cu yard and you must order at least 3 yards. Once it is set you just can not move the stuff around. The little 80 pound bags at the home center make 2/3 of a cu foot. So it will take 41 bags to make a cu yard plus the mixing by hand. You might get a better price on the blocks if you order 4 pallets of block and have them delivered. This would be from a concrete company not a home center. Please ask lots of questions the concrete company could also supply the number 5 rods at a better price.

Blueberry's picture

Well I can be dangerous with a credit card. Have no idea about cost but ready to go. or you could start collecting metal or plastic drums. This one is a lot more money!!!! Just need a few blocks to get to the right height. With a little blue smurf pipe and poly paper instant cold frame.

David Trammel's picture

Ran across this tutorial on Youtube

The author has been experimenting with making concrete sides for his raised beds which can be modular and pin together. He originally used common Portland cement, but the panels were heavy because they needed to be a certain thickness. He used plastic pipe and metal pins on the ends to join the panels and needed a certain thickness least the panels crack at the corners.

He thought he could make the panels thinner and therefore lighter by using a stronger cement. He found a cement called "CSA" or Calsium-Sulfo-Alumanate. Typically used in mortar. This resulted in a panel 40% lighter.

As someone who did a lot of molding with silicon and wood forms in Hollywood, his tutorial is amazing and his method is probably going to be how I make my raised beds at my sisters instead of partitioning blocks.

Watch the video if you thinking of using raised beds.