You can easily get a cheap $1.99 water spray (as above) from any Craft or Hardware Store, but it looks tacky and frankly, uninspiring to a child.
Stick a few Space Alien stickers on it, and tell your child to ‘shoot’ the monsters growing at your garden / balcony. (It’s really an excuse to get the little one to help water the plants but who needs to know right?)
Image from: http://goo.gl/ydrmck
