when i grew in soil i used to use a 10ltr bucket, with a small pond pump on low flow connected to a 7 day timer. The flow tube was just placed on the top of the pot with an adjustable tap on the end to ensure you only get a limited flow of water. You have to play with this to get the flow right. It was timed to come on for 2mins every day. Found this was more than ample to keep my plants alive while i was away. just don't use a big bucket of water as if you get the flow wrong you'll come back to a flood