- The tube coming out of the air pump goes through a valve (I'll explain this later), then into the top of a water bottle, via a small hole so that the tube is a tight fit. The tube does not go far into the bottle, as it should not come into contact with the water in there.
- Another tube comes out of the bottle top, again via a tight hole, but this tube goes all the way to the bottom of the bottle. The other end is connected to the water reservoir in which the plant pot sits.
- The bottle is filled with just enough water to fill the reservoir to half way up the pot.
- When the air pump is switched on it pressurises the bottle and pushes the water up the tube to the reservoir. When all the water in the bottle is gone then the air pump will push air through the water in the reservoir, which is actually good for the plant roots.
- When the pump is switched off the water in the reservoir will gravity flow back into the bottle, but this can only happen if there is a a small air leak in the system, else an air lock will be formed. This is where the valve comes in, as this allows an adjustable amount of air into the system. It's necessary to balance the valve so that not too much air escapes, as the pump would not be able to push the water, but enough to prevent an air lock. I don't think that these valves are actually meant to leak air at all, but fortunately they do. Alternatively, a two way valve could be used if the single valve is not leaky.
- The system will be set on a timer to come on a few times in the day and to run for a yet undetermined time, allowing the planting medium to get sufficient moisture and aeration.
My other horticultural hobby