Most weeks, your share includes a member of the allium family, be it onions, scallions, shallots, or leeks.  All of these have an oniony flavor, some stronger than others.  Garlic is also in the allium family, but is not part of the share this year because garlic crops are planted in the fall, and we didn't have a lease on the farm until January, missing the opportunity to plant last year.

Selecting:
Sweet Onions: You will find the onions harvested in the spring and summer have a sweeter, milder taste.  Choose sweet onions that are heavy for their size without any bruises or blemishes.

Shallots: Shallots are much smaller than onions, but they are not baby onions that haven't grown up.  They are a distinct vegetable in the allium family.  Choose shallots that are firm and heavy for their size.  Avoid shallots that are sprouting or have any soft spots.

Scallions: Select scallions with bright green tops and a firm white base.  Avoid bunches with wet or wilted tops, which will spoil faster.

Leeks: Smaller (i.e. skinnier) leeks are more tender.  Choose leeks that are firm and straight.  The leaves should be dark green and the bulbs white.  Avoid leeks that have yellowing or wilted foliage or bruised bulbs.
 
Storing:
Sweet onions: Due to their high moisture content, sweet onions will not keep as long as cured onions (like the ones from the grocery store).  Eat them within a few weeks.  You can wrap each onion separately in a paper towel or newspaper and store them in the refrigerator in the crisper drawer.  You can store them in a paper bag, but do not use a plastic bag. 

Storage onions (with dry skins) are harvested later in the season.  These should be stored in a cool, dark place that is dry and well-ventilated. Moisture is a storage onion's enemy, so do not store these onions in plastic bags.  You can store onions in pantyhose, separating each onion from the next with a knot.  The pantyhose allow the moisture to continue to evaporate.  Or try using perforated paper lunch bags.  Onions should not be stored near potatoes which give off moisture that accelerates the decay of the onions. 

An interesting fact I learned is that the onions that are cured for storage are the ones that make you cry.  The sulfurous compounds that irritate many people's eyes are the same compounds that help preserve the onions for longer storage.

Shallots can be stored in a cool, dark place, much like storage onions.  They will keep for up to 2 months.  If they sprout, you can still use them.  The sprout has a stronger, more bitter taste than the shallot flesh, so if you don't care for it, remove the sprout before using. 

Scallions: You can store scallions in a plastic bag in the refrigerator.  Remove the rubber band, if any, and pay attention to the outer layers.  As they begin to decay, you should remove the slimy layers to help the remaining scallions keep longer.  I haven't tried it, but you can also keep the scallions in a jar with an inch or two of water, in the refrigerator (covered with a plastic bag) or on the counter.  Change the water when it gets cloudy.

Leeks: Store unwashed leeks in a plastic bag in the refrigerator.  The plastic bag will help retain moisture.  You can trim off the dark green tops, but keep the roots intact until you are ready to prepare them.  The leeks should keep for a week or two.

Freezing:
You can freeze peeled onions, diced or sliced into pieces, to use later in cooking.  First, freeze the chopped onions on a baking sheet, that transfer to ziplock bags or containers.  The frozen onions can be stored for 3-6 months, but they will lose flavor the longer they are stored, so try to use the onions within 6 weeks.  In addition, be careful what you store the onions next to as they might share their flavor when first frozen.

Other alliums like shallots, scallions, and leeks can be frozen for cooking (dice or slice them first) for up to 3 months.  Follow the same instructions given for onions.

Preparing:
The alliums in your share are typically used as aromatics to accent a recipe.  Sweet onions won't have quite as strong a flavor as the others, but are delicious raw in salads or on sandwiches or burgers.

If you haven't had caramelized onions, treat yourself.  The natural sugars concentrate as the onions cook down, turning a dark burnished color. Caramelized onions are versatile and can be used in many recipes, such as to top a pizza or dress up pasta.  Here are instructions for caramelizing onions.

Some people recommend only using the white part of a scallion, but I use the whole thing.  Use your own judgment.  If you choose not to cook with the green stalks, consider adding them to a pot of stock.

Leeks, more than other members of the onion family, seem to trap dirt between the layers.  It's important to clean leeks well before cooking.  Split the leek in half, through the root, and rinse the dirt from between the layers.  If you are using sliced leeks, you could also slice them first, and then swish them in a large bowl of cold water.  Lift the leeks from the bowl, leaving the dirt and grit behind.  Depending on how dirty the leeks are, you might need to repeat this with a few changes of water.  Most sources recommend using only the white and light green part of the leek.  The darker greens make a good addition to stock. (Check out this blog post with pictures of prepping leeks.)

A tip from Jackie is to throw the dark green leek tops in a freezer bag with other trimmings and, once in a while, use them all for vegetable stock. If there is just one vegetable kept for this purpose, she makes leek tops a priority, both for their flavor and to salvage the high proportion of trimmings relative to useable leek.