My herb patch was established after visiting the Eden Centre in Cornwall. Outside the tropical biome they had very attractive stripes of Cornish vegetables and shrubs running up the slope. I thought it would be fun to grow stripes with different sorts of chives. Although not strictly an organic gardner I like the choice offered by the Organic Gardening Catalogue (http://www.organiccatalog.com/catalog/) partly because of featuring more exotic variants of herb and vegetable seeds than most garden centres.
After looking at chives I was intrigued to find "Welsh onions" in the herb section. I had never heard of them before. They looked vaguely like spring onions and seemed to have a decent season length so I bought a packet of seeds just for a laugh. As can be seen in the foreground of the picture below they have thrived. There are garlic chives (with white flowers) and ordinary chives (purple flowers) behind them.
As the catalogue said they grow just like chives so I have harvested them just like chives. They are bigger than spring onions but the tubular leaves have a finer texture - they are giant chive leaves - but have a very similar taste to spring onions. You can cut the tubes at the base and chop them finely for say a salad - as an alternative to spring onions - however it is important not to let the tubes grow too long. We usually cut them at roughly 30-40 cm long; beyond that the leaves develop yellow spots, become coarser and keel over.
As can be seen below the Welsh onion is like a big brother to a spring onion which will typically grow to about 25 cm (the one below from a supermarket has had its roots and leaf tips chopped). The maximum height is about 50 cm.
From time to time Welsh onions have been a useful insurance policy for when we have run out of normal onions for something like a stir fry. Of couse they need to be added very late as they cook in no time at all. Just chop up a number of tubes and you will get your onion taste from the leaves.Last but not least the neat thing is that - like chives - once they are chopped they just keep growing again. In not many weeks you can cut your next crop.