This inexpensive DIY project makes starting or growing plants a
whole lot easier by automatically keeping the soil at just the
right moisture level. All you need is a 2 liter bottle and some
string. ASBloom shows you how to make these clever planters on
the Skruben blog. Basically, you cut the bottle in half, and
thread some string or yarn through the bottle cap. Then invert
the top half into the base and add your plants and soil. The
yarn acts as a wick and the plants will take the water as they
need it. Even better for those of us with black thumbs: The
clear bottles help you see when the water needs refilling.
(Note: If you need a larger planter, you can instead use a milk
jug and some foam for your automatic watering needs.)