The smallest container we recommend you use is a 15 gallon fabric style container. The optimal container size is 25 to 30 gallons, but with proper care you can have good success in 15 gallon containers.
With no-till living soil you want to use worms, cover crop, and a mulch layer to start with. We also advise you use nematodes, rove beetles, and hypoaspis miles to aid in pest management. Collecting proper data via soil testing, sap testing, water testing, and the use of an Irrometer to aid in watering can all collectively help with a successful garden. As well as ensuring a diverse array of biology in your soil.
The benefits of no-till livng soil is that the water holding cpaacity will increase over time. The key thing to keep in mind is that you want zero water runoff when watering. If you are getting runoff then you are watering to much. Typical users will water 3 times per week, and the amount will vary with temp/humidity, age of soil, indoor vs. outdoor, etc... Again, if you get runoff you are watering to much. Using this as a basic guide you will figure out how much water your situation needs.To water more exactly, we suggest using an Irrometer to measure the tension in the soil. This is a fairly precise devise that is low in cost, but can help to really dial in your watering needs.
We recommend that you use a sedmiant, and carbon filter to remove any chlorine, or chloromine. We have found that straight city tap water will run into issues over time, and this basic filtration helps to extend the longevity of your soil. If you are on well water it is still a good idea to use the same basic filtration to help get a more homogenous water source as wells tend to fluctuate in quality a bit especially in rainy seasons. RO water can run into issues long term as the minerals are removed form the water. As the RO water passes thorugh the soil it will pull the minerals back out. After a few rounds you may begin to see what looks like deficiencies in your plants when using RO. Reintroducing minerals when using RO water may alleviate this issue.