Friday, 17 January 2014

Saving Onion Seed, Including Shallots and Leeks - Part I - The Basics

It seems an odd time of year to write about saving onion seed, but in fact this is where it needs to begin: first, choose your onions. The seed catalogues available now are the place to look, and since onion seed should be started indoors in mid to late February, now is the time to place your order.

Most gardeners buy onion sets (tiny onions) and plant them in the spring, then harvest fully-grown onions in the early fall when the greens die down. However, these onions are almost certainly not suitable as a source of onion seed. If you want to save seed from onions, you will need to start by growing onions from seed. There are two main reasons for this.

The first, something I have only just clued into, is that there are varieties of onion seed that will grow useable onions in the first year, and there are varieties of onion seed that should be sown with the production of sets in mind. Actually producing sets yourself is a fairly complex and time consuming system of onion production, and there are very few heirloom or open-pollinated varieties available for this type. Amish Bottle Onion is, in fact, the only one I know of, and it is really quite rare and hard to find.

The other reason to avoid saving set-type onions for seed, is that as mainstream commercial varieties they are almost certainly hybrids. And onion hybrids are almost always male sterile, meaning that almost any attempt to save seed from them will fail. Given that onions are biennials, and don't flower until the second year (or third, from sets) that's a lot of time spent waiting for something that may or may not happen.

So, unless you are specifically looking for an onion to produce as sets, you need to look for open pollinated varieties of onions that will produce a usable onion in one season and go to seed the next. As I mentioned already, that will be most of the open-pollinated onions available in seed catalogues. Here in Canada you will prefer  "Long Day" onions - onions are affected by the number of hours of daylight in a day, and different varieties are required in different latitudes. This shouldn't be a problem if you are buying seed from local suppliers, and we can in fact produce decent onions from "Short Day" varieties,  unlike folks in the south, for whom the reverse is not true (that is, they cannot get reasonable onions from "Long Day" varieties).

Hybrid onions are becoming more and more prevalent amongst onions grown from seed to bulb, so you will still need to take care in choosing your onions. If an onion is sold as an F1 hybrid, you can assume it is one and avoid it, but not all hybrids are labelled. I bought some "Red Marble" onion seed one year, not realizing many seed companies, for some reason, don't label it as an F1 hybrid. It is one, though. Fortunately for me it also failed to overwinter before I realized this. It is safe to assume that ALMOST ALL hybrid onions have Cytoplasmic Male Sterility at this point in time, and are thus going to be useless for producing seed. If you wish to allow different varieties of onions to cross, do not be tempted to use the hybrids as mother plants (they will produce seed if pollinated, but no pollen). The CMS will be passed on and is next to impossible to eliminate from your gene pool once it is in.

All onions - and shallots, if they flower - will cross with each other, but not with leeks. All leeks will cross with each other, but not with onions or shallots. Therefore, if you wish to keep your line pure, you can only grow one of each to go to seed each year. Unfortunately onion seed is a very poor keeper. It will be best the first year, adequate when heavily sown the second year, and yield poor germination the third year - and that assumes that it has been properly stored. Proper storage is well wrapped up in the freezer, when not being used. Since onion varieties need to be isolated by anywhere from 1/4 of a mile to a mile (depending on who you ask and the number of obstacles in between them) in order to be kept pure, the number of onion varieties a person can maintain will be pretty limited. Of course, this assumes you are aiming for near-perfect isolation, which is a level of purity most of us don't absolutely need. Still, check around and see what your local fellow-gardeners are growing. The good news is, not too many of them will be letting their onions go to seed  - unless maybe they read this post!

Onions are outbreeders pollinated by insects, and are subject to inbreeding depression; that is, the quality of a variety will deteriorate if you do not allow a sufficient  number of onions to go to seed together. I've seen recommended numbers ranging from 18 to 200 onions. My own personal view is that 50 to 75 is reasonable for the home grower who can improve their seed with new stock every few years. More good news is that I think there is no reason not to replant onions for seed very closely together - it may make them lank and weedy, but at that point who cares?

In order to get the higher number of onions you probably need to plant around 400 seeds in the hope of getting at least 300 seedlings. Plant out the 200 to 250 best seedlings, then continue removing weak or non-typical plants as the season progresses. If they are storage onions, discard any that don't die down cleanly at the end of the season. As they store, discard any that sprout, become soft, or show signs of mould. Hopefully, when spring comes and it is time to replant them, you will be left with a number that is within the range required. See my post on selecting plants for seed for more things you should be considering. When you replant your onions, do not plant them too deeply - observe, when you harvest them in the fall, how they situated themselves and aim to reproduce that. Photos taken before harvest time will be useful.

If you really, really want to grow more than one variety of onion for seed in a year, there is a way to do it, if you are prepared to do the work, or so I am told. Keep your onion beds as far apart as you can reasonably manage, and when they flower, cover them both with row cover, well sealed at ground level, just before the first buds open. On alternate days, or mornings and afternoons, remove the covers from one at a time, and make like a bee with a paint brush. The more thorough you are, the better seed set you will get. I've also heard of one fellow who glues dead bees to the end of a wooden coffee stirrer - he says they work better than paintbrushes. But that's some real dedication. When you are done, cover them up. Do this daily, or every second day, for a week to a week and a half. Then, keep the flowers covered until all the blossoms are done and the seed ovaries are starting to swell.

Leave your fertilized onion flower heads to mature until the seed pods are fat and round, and start to change from green to yellow and dry out. You want to pick them when they are fully mature, but not falling out of the seed pods yet. Tie them in a bunch, suspend them into a paper bag, and hang up to finish drying. A lot of seeds should fall into the paper bag. To finish cleaning them when they are completely dry, crush the seed pods and pull out as much debris as you reasonably can. Then put the onion seed and remaining debris into a large bowl and fill it with cool water. Stir it gently around. The debris and low quality seed will float; skim them off. Drain the remaining good seed, blot it well with towels, and get it dry as fast as possible. I spread it out on paper towel and dry it in my food dryer, with the fan blowing but the heat off.

Thus far I have been refering mostly to onions. Pretty much everything I have said applies to leeks as well, with the note that I don't bring them inside to store over the winter - I leave them in the ground over the winter and do my selecting in the spring, by eating the substandard specimens as spring greens. And of course, anything not tough enough to have made it through the winter is automatically eliminated. Elephant garlic is a leek, not a garlic, and should not be allowed to flower with your leeks for seed (unless that 's what you are growing).

Shallots have traditionally only been reproduced vegetatively. That is; you plant one bulb in the spring, and over the summer it splits into a nest of 6 to 12 bulbs. Potato Onions are basically a form of shallot, but one more like regular onions - traditional French shallots have a distinctive mild but garlicky quality. In the 1990s Dutch vegetable breeders induced some Dutch shallots to bloom, and crossed them with onions. They refined the resulting hybrids, and now nearly every shallot you will see for sale is the result of hybrid seed, not vegetatively reproduced bulbs. They are so much cheaper to produce that it is now practically impossible to find the true French shallots for sale, which still only reproduce by splitting. If these modern shallots are planted and allowed to bloom they will certainly cross with any other onions in bloom at the time.

If you plant shallot seed, or plant hybrid shallots, you can expect that it is likely that Cytoplasmic Male Sterility will be present. The one notable exception that I know of is eschallions, also known as Banana Shallots or Cuisse de Poulet du Poitou, which are a traditional French variety grown from seed. By sheer good luck, I planted another hybrid shallot with them that was self-infertile but apparently not male sterile, and they crossed and produced a lot of seed on both sets of plants. "Zebrune" seems to be the name of the most common open-pollinated strain of eschallions. There are hybrid eschallions out there as well though, and all the usual caveats apply.

All of this assumes that your goal is to keep a particular variety of onion, shallot or leek true to type, genetically sound and in perpetuity. If you wish to sell or trade seed under the name of its specific variety, or cultivar, then this is what you must do. However, that is not always going to be the goal in saving onion seed, in which case there are other points to consider. I'll be talking about them next week in Part II.

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