Boiled Eggs: Don't throw out the water you boil your eggs in. It contains tons of calcium plants love. Let water cool and dump it on plants. Save egg shells, rinse them out really well, crumble, then mix in with dirt and/or potting soil before planting.
I never knew how to Harvest Cilantro without killing the plant. This site has all kinds of tips for growing, harvesting, storing & recipes for all herbs.