I find it hard to imagine a meal cooked without one of these very versatile plants. Often refered to as the onion family all members have a distinctive smell, caused by common sulphur compounds. Many produce by vegetative expansion as a preference although they can all seed.
Cultivation
Take a careful note of planting locations when growing non-seeding allium species. Sometimes un-harvested bulbils get mixed with next seasons variety and differnces may not be obvious.
Plant seeds in the Spring and pull mature bulbs in Autumn. Save only healthy, true-to-type bulbs for replanting and eat the rest. Store in cool dark areas and replant bulbs in the Spring.
Pollination
Allium flowers are perfect, but are unable to self-pollinate because the anthers shed pollen before the style and stigma are receptive. However flowers open gradually over a month, so on each seed head, pollen and receptive stigmas coincide. The flowers are pollinated by insects, mainly flies and bees. Most home seed savers isolate varieties rather than deal with caging or daily hand-pollination.
Hand-pollination should be done for 2-4 weeks for good seed. Tag then bag at least 10 flower heads of each variety before the flowers open. Once they have started to open and whilst watching for insects, remove the bags and use a fine haired brush to transfer pollen between open flowers, on different heads. Do them all twice to make sure some flowers are pollinated by other plants then bag up the flowerheads and repeat daily. Remove the bags when all seed has set.
Isolation
Varieties within the same species should be isolated by up to 3 miles. Otherwise use alternate day caging.
Harvesting
It is very important to rogue alliums that are to be saved for seed production. Remove plants with off-type foliage early in the growing season. Plants that bolt or start to flower during the first season should also be removed.
Let the seeds mature on the stalk and harvest as soon as they are dry. If left too long the seeds will shatter and be lost. In wet weather cut them off and dry on a sheet inside. Seedpods and seeds are easily seperated when dry, crush then winnow or blow.
Chives – Allium schoenoprasum
Common chives look like tiny clumps of onions, are perennial and grow for years. Each year a few plants produce purple-flowered seed heads. Common chives do not cross with any other common allium species.
Garlic Allium sativum
Garlic is grown vegetatively from individual cloves. After harvest, they can be stored in the same way as onions. It is usually planted in Autumn and mulched for the winter. It is ready to harvest when the plant’s top goes yellow and bends over. Dry the bulbs inside for a week before storing them in bags or braids. After curing, garlic may be stored in paper bags or hung in braids. Bulbs for planting should be kept in the dark at 35-40° F and 60% humidity.
Garlic Chives – Allium tuberosum
Garlic chives are like miniature leeks that taste of garlic. They do not cross with any other allium species.
Leek – Allium ampeloprasum
Leeks tolerate freezing temperatures and are more resistant to diseases than onions. Leeks can be overwintered under mulch in many areas where winters are not extremely cold. Otherwise dig them up and store in a root cellar, at 320 F. and 80-90% humidity. Plant next spring in a prepared bed.
Leeks will not cross with any other allium species. Unlike onions the seeds are more tightly encased in their seedpods so immediate harvest is unneccessary. After 3 years in good conditions the seed has a 50% germination rate.
Onion – Allium cepa
Onions belong to the genus Allium and species cepa. which includes several groups. The Aggregatum group includes onions which divide vegetatively. Biennial onions seed producing onions belong to the Cepa Group.
Seed-producing onions are biennial and require two growing seasons to produce seed. Harvest after the first growing season when the tops begin to dry, then dry the bulbs in shade for 10-12 days. Afterwards, remove the dry tops or braid into strands. Store between 0 and 10 ° C.
Onions then have a rest period where they will not grow, then enter a dormant phase where they will sprout if put in the correct conditions. Onion seeds should be harvested as soon as the seeds are mature and the pods start to dry. In good conditions the seeds will last 2 years with 50% germination.
Tree Onion – Allium cepa proliferum
Some of the top setting onions (Allium cepa, Proliferum Group) produce fertile flowers which can contaminate nearby seed-producing onions.
Welsh Onion