Know your onions for seed sowing

Onions ready for pots. Picture by Tom Pattinson.
Onions ready for pots. Picture by Tom Pattinson.

Sowing seeds in the first week of a new calendar year is one gardening ritual I always look forward to.

And although there’s an awareness that up to a fortnight might pass before the beginnings of germination, so high is the anticipation that I take a peep every day, full of hope.

Onions are always first on the agenda and they are the large show type, grown for fun and kitchen use rather than exhibition. Last week I managed to get three strains sown.

The first was saved from an Ailsa bulb two years ago, but after storage in a cool, dry place, it will still be viable. Next came Robinson’s Mammoth, which has performed well over the seasons, and friend Alan, who always does well at the local Coach Inn show, provided the third.

My onions are sown into John Innes seed compost, which is soil-based and retains more moisture than others. This is a useful buffer against the seedlings drying out, just as J.I. potting compost is when they’re transferred to pots at the shepherd’s crook stage. I also find it useful for later handling of seedlings to sow onions or leeks in rows. These are fashioned in the tray by making an impression with a pencil or edge of a short ruler.

Sowing exhibition onion seed in late December is fine for a local show, but top exhibitors aiming for national onion events need a flying start. No sooner is the show season over than next year’s plants are being sown. With the aid of supplementary lighting, the problem of shorter days can be overcome, additional warmth provided where necessary. As our seeds are being sown, there will be well-advanced young plants in greenhouses and polytunnels throughout the north.

Young plants of show onions can be bought at a cost, advertised in gardening magazines. A typical example is 12 plants for £16, but for me there is more satisfaction in producing your own. The starting point is securing a mature bulb of proven pedigree. Friend Alan is a kindred spirit in this respect. We both save a big shapely onion after show time each year, treating it like the biennial plant it is.

Over a period of eight months in a growing year, onions will develop from seed into mature bulbs that we lift and dry for storage and use over winter. By the end of January it’s not unusual to see small roots emerging at the bulb base, a sure sign it’s ready for the second phase; to grow on and produce one or more seed heads. Placing them atop a pot filled with decent moist compost is all the encouragement they need.

Last October Alan gave me such a bulb and it has spent the past two months standing in the conservatory. Last week, the signs being there for action, I started the process.