Onions and Shallots

Onions are a very satisfying crop to grow, but do need a fair amount of effort in order to get good results.  However, they are also very cheap to buy, they store well, and it is difficult to tell home grown from shop bought based on taste, so are not always the first choice for the home gardener.

They are often a key show vegetable, often with several categories just for them, for example, largest onion, onions under 250g (“normal onions”), shallots, pickling shallots etc. 

My preference is to grow from seed, as I have found the results better, and less likely to bolt (more of this later).

Shallots

Shallots are probably the most useful of the onion family to grow for the kitchen, as they are harder to get hold of and apparently have a sweeter flavour than a standard onion.  I am not 100% convinced! For the kitchen, I recommend growing from seed, and starting the seeds indoors in late February.  There are many varieties to choose from, but the most common to grow are Zebrune (long pinkish shallots), Ambition and Matador (both rounder, brown shallots).

Once the shallots have germinated, thin out and plant into individual cells (24 cell inserts are fine for shallots), and then in April plant out into the final position.  You can plant them quite close together as they do not grow that big.  Harvest will be mid to late June depending on the weather.

For vegetable shows there is only really one shallot to grow, Hative de Niort.  These are grown from last year’s shallots and are hard to get hold of (and expensive, 5 shallots will cost £15-20).  They also do not keep that well, so I plant these in the autumn under cover (greenhouse or polytunnel).  Harvest in mid to late June.  The weird thing about these shallots is they get rounder during storage.

Hative de Niort shallots at the Wroughton Show

Pickling Shallots

These are no different to normal shallots, just smaller.  Most shows stipulate that they are not to exceed 30mm diameter.  I tend to use the shallots that are the runts of the litter! Personally I prefer a slightly bigger shallot for pickling.

Pickling shallots at the Wroughton Show

Onions under 250g

These are what most people would class as normal onions.  There are many varieties to grow, and several approaches.  Of late I have had better results using overwintering varieties; the most common onion to use for this is Toughball.  These are started late October, inside, grown on in cell tray inserts and planted out in early winter (late November/December).  You can also start these seeds late winter, and plant out in April/May.  This year I overwintered these onions in a polytunnel, a giant tent cloche, in pots in the greenhouse and directly outside in soil.  I started harvesting all of them in mid-May and those directly planted outside in soil did as well as those planted in the polytunnel. For showing, harvest when the diameter is 25cm/10 inch.

Perfect onions, unfortunately not mine!

Giant Onions

For all larger onions you will need to start the seeds in October and grow under artificial lights before planting out in late April/May (or in February in a polytunnel).  The current world record is 8.9kg, and to grow anything approaching this you will need to source specialist seeds, often directly from champion growers.  For slightly smaller giants, Kelsae or Ailsae will grow onions 1-3kg.

I have grown all these in 30 litre tubs, which I put in the polytunnel until the weather starts to warm up (early to mid-May).

All giant onions are good for eating, and apart from size are indistinguishable from smaller onions in taste.  Just remember that most recipes do not mean a 3kg onion when calling for “one large onion”! 

More perfect onions, this time very large ones (and not mine)!

Onion Problems

I have two main problems with onions in my garden -  bolting, and white rot.

Bolting happens when the onion sends up a seed head.  In most cases this leads the bulb to stop growing and also means that the onion will not store.  You can still use the onion, but preferably immediately.  It also means the onions is no good for showing.  Onions are biennials, which means they grow over two years, the second year is when they should flower.  Sometimes they get confused and go to seed in the first year, this is usually associated with drastic changes in the weather.  So too much heat, too cold, too much water, too little water, all can lead to bolting.  From personal experience, a very dry spring and then too much rain seems to lead to more bolting.  I lost most of my onions this way last year.  The giant varieties seem to be less prone, and onions grown from seeds seem less likely to bolt in my experience (despite the claims that heat treated onions sets are less likely to bolt).

White rot is a major problem and can infect the soil for many years.  There are no treatments available. You will know if you have this, the onion rots from the roots and will look fluffy and white under the soil.  The onion will also smell horrible.  If the infection is not too severe you can chop off the worst of the rot and use the rest of the onion.  If you spot white rot, lift the onion and some of the soil and dispose of it into the rubbish or bonfire (not into the compost heap).

I have found that white rot affects all onions, garlic and leeks, but the smaller onions and shallots seem to be the most vulnerable.  The giant onions seem less affected. Overwintered Toughball seems to be mostly unaffected.

If you are growing on an allotment onion fly and allium leaf miners may be a problem.  I have not had the pleasure of them so far on my vegetable patch.  If this is likely to be a problem, then prevention is the best approach; grow onions under insect mesh.

Preparing onions for showing

Most show judges are looking for well ripened onions, so ideally you need to harvest your onions a month or more before the show and allow them to ripen.  You will likely lose marks at a show if you present a freshly peeled onion.

I wash the onions after harvesting, chop the roots off, and trim leaves to about 15cm above the bulb.  I then peel any damaged skin off and dry in my garage, inspecting every so often. Some growers use talc to help dry the onions.

Usually it is better to tie the onions with raffia.  The easiest way to learn how to do this is to search YouTube for some helpful videos.  The exact method of tying is not critical, the most important part is that they look neat and tidy.  I show my onions using small wooden rings to stand them on.

For showing giant onions, they are often shown as pulled, so roots cleaned up a bit and greenery removed, but not peeled at all.