Sprouting Garlic or Garlic Dos and Don'ts
There are two things you won't find in supermarket garlic. One of them is great garlic flavor and the other is a head of garlic that will sprout. The first limitation is directly related to the varieties of garlic planted by commercial growers. In California, for example, big time growers typically plant only two varieties of garlic, 'California Early' and 'California Late.' Their sharp, single-note flavor only hints at what great garlic can be. The second limitation of supermarket or "it won't sprout garlic" has a more complex explanation.
Left to its own garlic has an internal clock that ticks off the months of its pre-determined dormancy. When it reaches the end of its slumber a healthy head of garlic will struggle to shed its multiple wrappers and sprout two tiny spear-shaped leaves from each clove. The mechanism by which garlic keeps time is roughly understood. We know that dormancy is maintained by an exact balance of plant hormones that are constantly produced and destroyed within specific tissues of a garlic clove. But this balance is ultimately unstable as hormones promoting sprout formation gain the upper hand.
The exact time at which garlic will sprout is influenced by three principal factors: the variety of garlic; storage conditions and the presence or absence of man-made sprout inhibitors. Hard neck garlic (ophio garlic) has a short dormancy (4-5 months) while soft neck garlic can slumber for nearly twice as long (6-9 months). But no healthy, untreated garlic will sit on the sidelines forever. It is a minor manifestation of nature's power and inevitability that the garlic clock runs out and sprouting begins.
Which brings us to temperature and humidity. Extremes of humidity work against sprouting. Too little humidity (such as a kitchen refrigerator) will desiccate garlic. Too much humidity will cause rot. Temperature can also be tricky. Frequent fluctuations in temperature triggers sprouting so holding a constant temperature is important. Also of importance is the temperature itself. The optimal temperature for storing garlic depends upon on the target market date. The longer the needed storage, the colder the temperature required. But colder temperatures have an effect on garlic called "vernalization." This means that garlic stored in the cold will sprout very quickly once placed in the warm display bins at Safeway. To mitigate this phenomena cold-stored garlic requires conditioning and drying prior to market. More time, more work.
In order to manage the complexities of storing produce scientists and commercial industry have developed a number of techniques that inhibit a plant's time keeping mechanism. Several chemicals are known to do this. CIPC, MENA, methyl bromide and malic hydrazide are a few of them and they are widely used on crops such as garlic, potatoes, carrots, onions and so forth. How these compounds disrupt the plant's time keeping mechanism isn't known in detail but some act by damaging plant DNA akin the way in which some anti-cancer drugs work in human medicine. The potency of anti-sprouting agents varies but when combined with proper storage they can add several months to the shelf life of produce. Hence we have unsprouted onions, garlic and potatoes on the shelves in Safeway, even in March.
A final and emerging method for inhibiting garlic sprouting is good ole radiation. Yes, those playful gamma rays are helping in yet another way. Zapping garlic with a Cobalt-60 irradiator seems to be more effective than chemicals and it's cheap. And thanks to the U.S. Department of Agriculture it has been legal to do so since 1986. The USDA has concluded that "an overwhelming body of scientific data from around the world indicate(s) that irradiated food is safe, nutritious and wholesome." You bettcha.
What I think is "overwhelming clear" is that radiation not safe for garlic. It kills an innate and ancient mechanism that garlic has relied upon for maintaining its life cycle. Less clear to me is whether consuming irradiated food is "safe, nutritious and wholesome." To be fair, I think it is very likely that it is "safe" in the sense that no harm can be demonstrated. But the terms "wholesome" and "nutritious" are loaded with potential meanings that have not been rigorously tested.
All of these weighty matters bring us to the consideration of my 2006 crop of hard neck garlic and specifically a variety called 'French Germinador.' It is a creole type garlic that has a beautiful purple-splashed outer wrapper. It is a rare garlic outside of Southern France but that is changing thanks to Seed Saver's and similar organizations. I store all of my garlic crop, including Germinador, in suboptimal conditions. I hang it under the cover of a walnut tree to shield it from the sun ("Do") but I make no effort to refrigerate it (that's a "'Do' but I Don't"). So when the Northern California rains commence and the first frost tickles the nose, Germinador's internal clock begins to ring. Rootlets emerge from the bottom of each clove in search of soil and primary leaves shoot up from the tips. By Thanksgiving half of my Germinador crop will have sprouted and the rest is close behind. The soft neck garlics Inchelium and Red Toche will keep longer but they too will begin to sprout near Christmas.
I figure that there is a life lesson somewhere in all of this time keeping and sprouting. We can and should defend a harvest's bounty with methods that are simple and natural. They are the "Dos." But we can also chose means that may be more effective but at a cost of destroying a minute and fascinating mechanism of life that we only dimly appreciate. For me, that's a "Don't." True, I may not have "fresh garlic" in March but I have something more valuable and interesting: a living, healthy plant that tells time and reminds me plant them at Thanksgiving.