As far as watering spikes go, Moonlight Mushrooms are probably the coolest ever. These handblown glass spikes look just like little mushrooms. Simply fill them with water and stick them into soil down to the roots. Best of all, when the sun goes down, phosphorescent speckles inside the glass begin to glow, producing 2 to 4 hours of soft illumination. Magic Mushrooms you ask? Sort of, but just for plants.
Moonlight Mushrooms - Glow-in-the-Dark Watering Spikes