Giant Onions grown in Self-Watering Planter

Giant Onions grown in Self-Watering Planter Having been to an exhibition and a gentleman approached me what my thought were in respect of growing giant onions in our Oasesbox. Initial thought I do not know. Thinking what Onions needs, loads of Water. 15 Litres should be enough. In 2020 we have grown giant onions successfully