Gardening – Growing your own: onions

FOR the time-pressed gardener, onion sets are a godsend. Onion seed can take a long time to germinate and it transplants poorly. It also needs a long season to attain a kitchen-ready bulb size. So it usually makes more sense to grow your onions from sets instead. Sets are one-year-old onion seedlings that are dug up while the bulbs are still immature. The bulbs are then gently dried, stored for the winter, and arrive in garden centres the following spring. I suppose you could say the sets are in hibernation at this time and you reawaken them by sowing them in your garden. I reckon garden centres hate to see me coming through their doors every time they get in a new batch of onion sets. I slow everybody down by hogging the onion display as I scrutinise each and every onion set that I place in my plastic bag. In the case of flowering bulbs such as daffodils and tulips, bigger is better. Big bulbs usually mean a large amount of stored food to produce brilliant blooms the following season. However in the case of onion sets, smaller is better. Any sets much larger than your thumbnail are unlikely to produce good bulky bulbs, instead they will tend to run to flower. The colour of the bulbs' skin should be reasonably uniform with no excessively dark, light, or green patches. Any bulbs with weak or spongy areas should not be planted, this is often a tell-tale sign of rot. Sowing your sets Onions from sets grow best in an airy, sunny location on fertile soil that drains well. Avoid at all costs soil that holds water or, on the other hand, dries out rapidly. Thankfully, onion sets are slightly more forgiving of poor fertility than onions grown straight from seed. Sets can be sown by simply pushing the bulbs down into soft, crumbly soil leaving the tips of the bulbs just above the soil surface. However, if you fear your soil is not soft enough, or that you may possibly damage your bulbs by planting this way, then you can always sow them into shallow drills instead. At 12 inch (30 cm) spacings, create flat-bottomed drills one inch (2.5 mm) deep, and then lightly press your sets into the base of these. After sowing, close the drills with soil, lightly firm around the sets, water well and label. Bird attack tends to be one of the main pest problems encountered by the growers of onion sets. These pests tend to pull up young sets root and all. Protection, in the form of netting across a few twigs, should be used during the emergence of the onion shoots. This protection measure is especially important if pigeons are a problem in your area. Harvest Once your onions display swelled bulbs, and stems beginning to yellow and topple (at about 18 weeks), then they are close to harvest. This can be encouraged along by manually bending over the stems once the leaves start to yellow. After a further two weeks, and on a dry day, you can begin to carefully lift your crop with a hand fork. Lift the onions completely out of the soil and place on trays, boards or some other dry surface that allows them season through sunlight and air movement. Any bulbs that are damaged or soft should be discarded, while all bulbs with thick necks or those which produced flower stems or heads should be used in the kitchen first, as they will be useless for storage purposes. If the weather is warm and dry, then outdoors will be fine for drying your crop. Otherwise drying can be carried out indoors and the onions can be placed on the windowsill of a shed or on shelves in the greenhouse. Drying should take about two to three weeks, and during this time you should turn the bulbs around a few times so as to allow light to season the skin all over. Remember, onions are the kitchen's most adaptable vegetable. If the sets you add to your garden are handled according to my selection and sowing rules, then you are well on your way to a delicious return from this season's planting. Next week, the potatoes go in. Until then, happy gardening and remember that a weed is just a plant in the wrong place.