Old Ted at the allotment says Boxing Day is best if you want big ones, so this year thatâ€™s what I aiming for, though if itâ€™s anything like last year, Boxing Day was spent hungover without a thought to onions!
Yep thatâ€™s the time to sow them according to Ted and he grows prize specimens and he also says he always grows them in the same bed each year with great results.Â
Onions need quite a long time in which to make a bulb â€“ hence starting on Boxing Day! However, January to early March will still produce great tasting onions.
So, what do we need to prepare for this seed sowing session? I will need some heat, Iâ€™m going to use one of those nifty window sill propagators, putting it on the window sill in the spare bedroom as it faces south, I will try to maintain a temperature of between 10-15 C. Using use multi-purpose compost, you can of course use seed compost, popping a couple of seeds into each cell, then sprinkle about 1.5 cm of compost over. They can take up to fifteen days to appear depending on the temperature.Â Onion seeds actually donâ€™t need light for germination, but as soon as they have they must be moved into the light.Â Keep the compost just moist and if both seeds germinate hoick out the weakest one.Â I will need to transplant these later on into 8cm pots, you can if you have the room or a heated greenhouse go straight for the 8cm pots, so I will transplant into 8cm fibre pots which will then be planted straight out, so bonus of no root disturbance.Â Â You can also sow the seed outside around the last week of March once the soil has warmed up a bit. Â ÂÂ
They will need to be hardened off, so when the temperature permits i.e. consistently above 5Â CÂ (40Â F) pop them outside during the day and back in at night then they should be ready to plant out late March early April, 10cm apart with a 30cm gap between the rows for hoeing and you will need to hoe, they hate weeds.
If I can remember, once a month I will give them a handful of blood, fish and bone. About every square metre should do it, sprinkle around the plants, jiggle it around a bit but donâ€™t damage those roots!Â Also keep them watered in dry conditions and stop watering and feeding once they have formed good bulbs as it encourages them to mature which helps with storage. Have a go!
PS â€“ I missed Boxing Day, make of that what you will!Â So the second or third week in Jan it is then.