Flora Windowboxes are great for outdoor growing! The planters hold one gallon of nutrient solution which eliminates daily watering. (Watering frequency depends on temperature - normally once every 5-7 days - 3-5 days in hot weather.)

LECA pebbles draw up nutrient solution to the plant as needed. If exposed to rain, excess water drains away through a drainage hole in the side of the window box. 

Flori Windowboxes are also great for growing herbs!