This is the best design I have seen for 5 gallon buckets, but its too expensive...Here you can buy wicking pots and big box stores. You add water to the bottom through a hinged spout you open.
https://www.amazon.com/GroBucket-Wa...jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==
