Water Tube self watering plant guard

I purchased this plant guard from Diggers Club. You put 3 stakes in around your plant then slide the tube over the stakes. Then you fill the lining with water. It gradually drips out over a few weeks through a hole pierced near the bottom with a plastic coil spring. When it's empty, you re-fill the lining again. They're a bit expensive at about $10 each.

They say its better to give a deep watering less often rather than continuous drip watering but this would be a good way to get new plants established. I've planted a globe artichoke in this one and it's growing really well so far. It even survived my 2 holidays when I was away for a couple of weeks each time.