Earth tied sub-irrigated lasagna garden in tote...

I needed more planting space along the boardwalk, I had just emptied this tote of biochar, and I needed a place to put the unfinished compost that I  was moving to get at the finished stuff.
I have been wanting to try sub irrigation in raised bed  that also had access to the soil moisture beneath.
The hole in this is tote  so small it probably isn't a good test.
It should be a good test of the basic idea of a tube delivering water to a buried open topped container.

I like it.

With a few modifications in the overall design I'm sure the same concept could be utilized in a self watering raised bed. My only issue with the SWRB is it doesn't allow access to existing ground. The varieties with deep penetrating roots would suffer(certain radish,asparagus,etc.)
The key I think is getting the water to pass thru the materials(BioC,  HotPost) and then be dispersed throughout the bed with the water in a uniform fashion not to be concentrated in 1 particular area. Another key would be accessibility to be replenished when the material is spent or needs a refill.

I thought of a design with a tub up above the bed itself that could be filled with anything, even have different chambers for different material separation that combined in the void below before leaving the tub. Screened below the chambers and at the outlet with maybe a 2' perforated pipe leading into the bed, like a drip tape concept. Even place a valve on the outlet so the tub could be filled and the material could soak and release more goodness.

This way even though you would still have to water the bed or tub in the design. there's a few ways like materials in substrate that could retain the moisture. You could even have access to the pipe as it leaves the tub to just water the bed normally.
A timer could even automate the process on the tub and the pipe.

I have yet to implement it and many of my thoughts... I think too much...

good luck

I planted it out.
Most of the seedlings are tomatoes from a neighbor-he grew them in fast food paper cup!
I love the fact that almost everything in this photo was "free"

This is one of my bicycle wheel beds.
It has a tube feeding into an(smaller) open topped container.

You mentioned a "hole" but... can it drain? I always try to put them up on a side so it will have a reservoir in deeper containers. I just can't see any.
OOhhh, is that the deck I see,  hahaha , my bad.
Free is always good.