4 buckets and a 50L bag of compost.
Soil is a little nondescript. I would use the canna terra, a weak medium that you feed with a full range nutrient every time. You can expect water consumption of around 10L per day, so get a 5th bucket that you can mix up 13 in comfortably. This will lead to fresh oxygenated water every day, that's easy to adjust the strength of. With the chance of real air being pulled in as the water is used up. Deficiencies are unlikely unless you were to fancy yourself as more knowledgeable than canna. And if you did bugger it up one day, it's only the next day your rinsing it anyway. You can even oxy the shit out of it and have a more hydroponic view of things, if you do get real problems.
I like amateur friendly solutions. Terra gives a soil taste, without the need to make up a mix your stuck with.
So many options for you...