Garlic has been part of agriculture for at least 5000 years and is thought to have been brought to the Americas by Columbus. There is much folklore associated with it, from treating warts to fighting off vampires! Garlic, leeks, and shallots are members of the onion family (alliums) and are great cool-weather crops for winter gardens in our area. They are easy to grow and do not take up a great deal of garden space.
Growing conditions are similar for most members of the Allium family. They need reasonably fertile soils (amend with compost), but must have good drainage as bulbs may rot in soggy soils. They also like a sunny spot. The links given below each variety give more information on how to grow them.
Garlic
Garlic is best planted in October or November and will be ready to harvest in June or July. It is started from ‘seed garlic', individual cloves separated from a garlic bulb. Good quality disease-free seed garlic from a nursery should be used, rather than grocery-store garlic. You can also use bulbs saved from last year's crop. There are many different varieties of garlic, with varying degrees of flavor and spiciness.
These fall into two main types: Softnecks are the ones found in grocery stores and have a flexible stem which can be incorporated into braids. California Late White and Early White are examples of softneck garlic. They store well. Hardnecks or Rocambole tend to have larger cloves and more flavor variations. They have a stiff central stem between the cloves, hence the name! They are better suited to a colder climate than ours in the Bay Area, and do not store as long as softneck garlic. Nonetheless, many of us grow hardneck garlic successfully.
http://ipm.ucanr.edu/home-and-landscape/onions-and-garlic/cultural-tips/
https://vric.ucdavis.edu/veg_info/garlicprodtips.htm
https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=43862
Elephant Garlic
This looks like a giant garlic bulb but is actually closely related to leeks. It has a milder flavor, with big flower heads and foliage reaching to 4 feet tall. Fun to grow with kids!
Shallots
Shallots are mild-tasting onion relatives and are much-used in gourmet cooking! They can be grown from seed, but often the individual bulbs are planted in a similar fashion to garlic and will form a new cluster as they grow. Drainage is especially important for shallots, as the bulbs will rot if they remain too wet. https://ucanr.edu/sites/mgscc2016/files/333041.pdf
Leeks
Leeks may be planted from seed, but also seedlings can be very economically purchased from a nursery. Leeks like regular water, but as with their relatives, good drainage is essential. They are often planted in a trench with soil being gradually added as they grow to create the blanched stems usually associated with leeks.
https://sonomamg.ucanr.edu/Vegetable_of_the_Month/Leeks/
Conclusion
Growing alliums in winter is a great way to keep your garden producing during the cooler months. If we end up having a good rainy season, these plants will be watered with free water. If not, keep watering during the dry spells so the plants continue to grow.
Help Desk of University of California Master Gardener Program of Contra Costa County (SMW)