I have recently visited every garden centre for 20 miles around in search of my Red Baron onion sets, but to no avail. This is the first time I have failed to get some. I thought I was just unlucky, but when I visited the Edible Garden Show at Stoneleigh a couple of weeks ago I realised I was not alone in my quest. Everyone seemed to be asking for them and while there I managed to find out why Red Baron is in very short supply.

I discovered that the Red Baron crop of sets is raised from seed in Northern France largely by one grower who subcontracts the growing out to several farmers in his locality. This year’s hard December also affected Northern France and low temperatures killed the crop, or most of it. As a result there are few Red Baron sets available. This is firm evidence that red-skinned onions are not as hardy as yellow-skinned onions. They certainly don’t keep as well. Shallots, also in short supply, were also hit badly by the weather.

Experience has taught me that red onions do best planted two to three weeks later than golden-skinned sets. My ‘Sturon’ (an AGM golden globe variety) are already in the ground and have been for two weeks. Other golden AGM onion varieties include ‘Centurion’, ‘Hercules’, ‘Jetset’ and ‘Setton’. Red Baron’ ( also AGM) is the best red onion by a mile. ‘Red Spark’ also got an award but isn’t available. Monty Don, on his return to Gardeners’ World, was seen sowing his red sets into modules to give them a head start. This could work very well on heavier soil because (like most bulbous plants) onions prefer good drainage.

Onion sets are planted six inches apart in rows nine inches apart on well-drained, fertile soil with their noses poking out. Shallots are smaller, but they need more space because they splay out and produce a cluster of bulbs, as in the picture (above). They should be planted nine inches to a foot apart. They also need more warmth than onions. AGM varieties include ‘Golden Gourmet’, ‘Jermor’ (a yellow) and the red-brown ‘Pikant’ Shallots take 26 weeks to mature and onions take 20. Always lift them. Leaving them in the ground could encourage disease.

There are two types of sets on sale. The ordinary, cheaper sets are available between January and March, and I tend to use these. Heat-treated sets, which are less likely to bolt, come into garden centres in April, but they are pricier. Last year’s exceptionally warm and dry spring wreaked havoc with my shallots and onions. They grew poorly and, when it did start raining again, they did not recover. I know now that newly-planted shallot and onion sets must be watered in dry springs owing to their short, stubby roots. It’s also vital to weed between them. A small onion hoe is the best hoe a gardener can own.

The First Edible Garden Show, held at Stoneleigh, just north of Leamington Spa, was a huge success. Crowds arrived, most dedicated gardeners and allotmenteers. As a result a larger show will be held next year between March 16-18.