Onion sets red raygreat flavour and ruby colourthe exciting onion sets red ray is a true must have in your vegetable patch or allotment. This is a uniform variety that boasts an excellent ruby red skin, accompanied by an amazing flavour. Thanks to its very strong root system, the onion sets red ray is a very productive variety that is suitable for long term storage.heat prepared onion setswhy buy heat treated onion sets? It's frustrating when your beautifully forming onions decide it's time to develop seed and send up a flower stalk. Heat treating is a process that we carry out on your behalf to prevent this happening.