If it weren’t for that blasted fly, I’d be queen of onions. The allium leaf miner shreds any whiff of the enzyme alliinase – it takes down leeks, bunching onions and garlic, and the only sure way around it is to barricade your crops with the finest of mesh netting or confuse the female so thoroughly with a blanket of other plants that she can’t find her way through to your crop (mint is quite effective as long as you can keep it from taking over). For the last few years I’ve been prepared to battle only on behalf of garlic, but I miss shallots, so I’ll darn all the holes in my mesh and protect those, too.
You have two choices with growing onions and shallots: you can either sow in early spring or plant as sets. The latter are immature onions or shallots that grow into mature bulbs. These are fairly easy to grow; you just nestle them into the soil so only the neck is sticking out.
There are two windows of planting: autumn and spring. Autumn sets are from cultivars that are less sensitive to cold exposure, which induces early flowering (and makes for a poor bulb). ‘Electric’, ‘Senshyu’, ‘Radar’, ‘Troy’ and ‘Swift’ are all onions suitable for autumn planting; for shallots, try ‘Jermor’, the delicious ‘Eschalote Grise’ and ‘Yellow Moon’.
Truth be told, it’s a little late to be planting them now, as the aim is to get them all in by the end of October, but you can cheat and plant the sets in large modules or small pots in good compost and they’ll quickly catch up with the in-the-ground folk. You may be lucky and find discounted bags of sets. Sort through and discard any that are too small or shrivelled (buy two bags if necessary). You need to use the largest module trays you can find (or 6cm pots), as the bigger the root mass, the better. When planting out, place the sets 10cm apart with 30cm between rows, or in blocks 15cm apart in each direction.
This is also a good back-up plan if you have mice, squirrels or curious crows who will all have fun unearthing and stealing your sets if they are in the soil. You can use this module trick for broad beans, too. Make sure they are somewhere you can keep an eye on them and sheltered from the worst of the winter rain. They can be planted out in late winter, if the weather allows, or early spring. Over-wintered sets benefit greatly from a nitrogen-rich feed as winter wears on. Traditionally this is sulphate of ammonia or poultry manure, at the rate of 35g per square metre, but in the modules a liquid feed with comfrey will work just as well. This helps with growth and can also suppress premature flowering.
