[x55j33]

Whenever I've tried this, the plants rot in the water. What am I missing? Should I be using a filter? boiling the water first?

[fredrikholm]

The water needs to agitated and aerated. An air pump works great.

That, or pumping the water to create circulation.

[nl]

This, and keeping the roots in the dark (which decreases algae growth in the water)

[frankzander]

Normal compost soil ;)