Although since they refuse to die, you could consider it a hydroponic garden
Yes, it is rainy and cold and cloudy, and yes I built it at the bottom of a hill, but I had been here for 6 months and never had any issues with flooding, and this is despite the emergence of several large lakes nearby which did not exist in summer
Then Spring rolls around, I get a few days of boiling hot sunshine, I do the garden, and the moment I finish, we get the most consistently wet weather so far
Initially I realised my mistake was that, idiot that I am, I packed in several large rocks, thinking that because they do not absorb water, they will increase drainage - WRONG! they provide an impenetrable barrier through which no water can pass
After a month of this, I was able to dig up the herb garden with much effort and take the rocks out, and the pool immediately began to empty. I topped it up with more soil and perlite after that, but consistently bad weather means it keeps on flooding - Rosemary, Lavender and Thyme are all holding up, but the Cat Mint is fully submerged
If the sun ever comes out again, I think I will just build a planter