In a previous post, I showed the results of our best ever garlic harvest, which produced plenty of large, good quality, and well flavoured bulbs. Certainly the weather has been more favourable this year, although with a rather cold, slow start to the spring, yet I suspect the great improvement came from growing these autumn sown bulbs in the polytunnel. I have yet to find out how the outdoor, spring sown crop has fared, as they still appear to have a little growth left in them. As garlic benefits from a good period of cold to encourage the formation of separate cloves, the spring sowing can result in disappointing bulbs.
It has been a similar tale with the autumn sown shallots and ‘Japanese’ onions. These were planted in double rows in the narrow polytunnel borders, along the edges of the beds, leaving space down the centre so that the tomatoes and sweet peppers could be planted later in the year whilst the onions and shallots finished developing. Protected from the excessive cold and wet conditions that caused difficulty with last year’s crop, these developed very well indeed. The extra warmth offered by the polytunnel allowed them to get a good start before the winter cold brought growth to a standstill. They stood well during the winter, and put on excellent growth in the spring, producing useful bulbs early in the year.
We planted approximately 200 onions sets and 20 shallots, and as we also have a spring sowing outdoors to provide a later crop, we were able to start using the bulbs as soon as they had developed a useful size. We have been using these directly from the ground as needed for several months now, but harvesting the remaining bulbs was a little overdue. These were already reasonably dry, so were simply dug and spread over the slatted staging to finish drying before they are put away for storage. They will be used first, as the outdoor spring sown bulbs should store longer into the winter.
We have tried various varieties of the hardy, overwintering onions, often known as Japanese onions, as they were first developed in Japan. Our best results so far have been from Senshyu Yellow, which I have found to be reliable, producing reasonably sized, firm bulbs, with a good, fairly sweet and not overly strong flavour. There are limited sorts available as sets in the Autumn, and being happy with Senshyu Yellow, I am rather inclined to stick with that one variety for the next crop. Senshyu Yellow is, as the name suggests, a typical sort of golden brown skinned yellow onion. I have sown the red onion variety Electric several times, but have always been a bit disappointed; they seem to suffer more in the cold and wet of winter. I decided not to bother with them last Autumn, although they may well have done rather better in the protection of the polytunnel. We did, though, plant some Red Barron sets in the spring, and these are just about ready to harvest.
Similarly, we have tried various shallots, and again, one variety stands out so far, Jermor. This is a French selection of the ‘Jersey longue’ type, hailing from Brittany. In my experience, it produces a very good yield of large, elongated, and very sound, firm bulbs. They have a rosy flesh with excellent flavour, and are particular fine roasted. Although the onions can provide useful bulbs much earlier in the year, as soon as these shallots are available, I rather prefer them for many culinary purposes, and they are of such good size that a very useful crop can be obtained from a handful of sets, and they are not at all fiddly to process in the kitchen. I may well plant more shallots and fewer onion sets for the next crop. As with the Senshyu Yellow, I am quite inclined to stick with this one variety, although one might wish for a slightly smaller bulb for pickling. I suspect, though, that some of our outdoor sowings will provide suitable bulbs for that purpose.
The outdoor sowings will also be ready soon, with the majority of stems already bent over and drying out. It is now a matter of waiting for a brief dry spell, before lifting the bulbs and moving them under cover to dry properly and cure the skins for storage. There are differing opinions concerning the harvesting of onions. It has long been asserted that one should bend the tops over as they start to mature. Although this advice is repeated in many modern texts, some now advocate leaving them to their own devices, arguing that bending them over can be detrimental to their storage properties. However, this is not so much a case of repudiating an ineffective method of the old gardeners, as the debate has raged for a long time indeed. For example, in The Domestic Gardener’s Manual of 1830, John Towers states:
It is often recommended to twist the stems of onions, or to bend them down, when they begin to turn yellow. The practice, however, is, I think, of very doubtful utility: for, if the leaves be of any use at all, if they still retain any activity, the result of bending must be an interruption of the descending juices; and if they have already begun to wither, but little effect of any kind can be produced.
With other authors, the matter is seen not as rule to be followed regardless, but as a possible benefit under certain circumstances. In Onions, and How to Raise Them, 1865, James Gregory, an American seed merchant, provides the following advice:
If the crop is quite backward, late in the season the necks of the onions are sometimes bent over to hasten the formation of the bulb. This is done by hand, or by rolling a barrel over two rows at a time.
This was not a new observation, for in 1806, Bernard M’Mahon, author of The American Gardener’s Calendar, provided similar advice:
…and if you observe that your onions incline more to tops than roots, you may with a long stick gently lay over their tops on one side, so as to bend them, and in a few days after, lay them back to the opposite side, which will check the ascent of the juices and cause the bulbs to swell.
Personally, I am inclined to leave them to their own devices, though laziness is a factor. Regardless of one’s view concerning the stems, there are two matters that should be attended to. First, although onions are biennial, stress caused for example by temperature fluctuations can result in some bulbs bolting. This largely applies to onions grown from sets; those grown from seed are far less likely to attempt to flower in their first year. Although all bulbs that produce a flower spike are then prone to poor storage and should be eaten as soon as possible, leaving the flowers to develop can result in a worthless bulb, and, in my view, removal of the flower head is beneficial, although there is generally some disagreement on this point. Second, is the reservation of any thick necked bulbs for consumption before those with thin necks, as it is the latter that offer the best chance for long storage.
The exact moment of harvest is a matter of judgement. One should not leave mature bulbs in the ground too long, as their storage properties may be impaired, or they may begin to grow once again. On the other hand, it is at the time when the stems begin to bend over that much of the swelling of the bulbs will occur, so, although they can be readily used as needed, one ought not to be too hasty to dig the entire harvest. Good curing of the bulbs, first in the sunshine where dug if weather permits, then undercover in dry conditions, is then important for long storage. Those with the inclination might wish to prepare traditional strings of bulbs; surely nothing looks finer, and they bring back memories of the strings of Roscoff onions brought over by the ‘onion Johnnies’. However, I have not yet found the time to prepare them myself. Otherwise, they may be stored on slatted shelving or in onion sacks. In any event, dry conditions and good ventilation are important. If stored in sacks or otherwise in close contact, checking for moulds and rots from time to time is worthwhile to prevent such problems from spreading through the entire harvest.