GARLIC IS OUR SIGNATURE CROP and it has been for 20 years.

It is, to a large extent, the crop on which our farm’s identity and reputation rest. Because we grow about 70,000 bulbs annually, when our garlic thrives we usually have a good year, even if some of our other crops don’t come in so well.

This year brought our earliest and biggest harvest yet of the plant that sometimes is affectionately referred to as the stinking rose. Since there was nothing particularly different about our practices in the field, the large yield likely was a consequence of the unusual weather conditions that prevailed during the crop’s most active growth phase.

We plant our garlic in late October and early November; it lies dormant for a few months until the soil warms again. This past winter was a very mild one—most of February and March were more like April—then temperatures moderated a bit but stayed unseasonably warm. The first garlic cloves broke ground on March 10, more than two weeks earlier than the earliest we’ve ever seen them, and a little more than three weeks ahead of the average emergence date in our area. This meant the plants got off to an early start and had more time to grow.

Then came the spring rains. Over a 4-week stretch between mid-May and mid-June, we got nearly 8 inches of rain, spread out nicely and in manageable quantities—about double the normal rainfall for this period. It was a real boon to the garlic, which likes to get its water early in the season, while it is still energetically engaged in above-ground growth.

In the month before harvest, garlic sends the energy it has captured in its leaves below ground to form a bulb. During this time, the plant’s leaves gradually turn yellow and its water needs are minimal. (In fact, a garlic bulb will cure more rapidly and store better if it is watered only lightly in its last few weeks and then pulled from relatively dry ground.) Again, we lucked out: From mid-June to mid-July, we received a scant 0.7 inch of rain, which suited the garlic just fine, though it didn’t exactly please our sugar snap peas, potatoes and leafy greens. The combination and timing of these climactic variables—a mild winter, copious spring rain and lots of dry summer sun (along with many hours of weeding) resulted in a high proportion of very large bulbs. Warm- to very hot temperatures throughout much of the garlic’s growing period probably also helped.

We sell our garlic by the piece, not by the pound. Since we receive more money for large bulbs than small ones, we naturally view large bulbs as a good thing. My homemade “garlic-sizer” is used to separate the bulbs into five size categories, from medium to colossal. The mediums measure between 1.5 and 1.7 inches in diameter and sell for $1 each; the colossals range from 2.25 to 2.5 inches and go for $2 each—they have a lot more mass. The other size categories fall in between.

In an average year, 15 percent of our garlic will fall into the super jumbo category and 5 percent into the colossal. This year, we netted about 30 percent super jumbos and 15 percent colossal, which gave a nice boost to the profit margin. Some of the bulbs were so weighty and so massive—more than 2.5 inches across—that I was tempted to add a sixth size category and price them accordingly, but I couldn’t come up with a suitable name for these monsters and let our customers share in the bounty of the harvest.

Other crops are jumping the gun too. This year, for the first time ever, we were able to offer our customers toma­toes and basil in early July. However, things didn’t go so well for our apples and peaches—the excep­tion­ally warm winter caused the trees to blossom weeks ahead of normal, making them vulnerable to frost—and an ill-timed frost is what they got. The result: no apples from our farm in 2012, and very few peaches. Many other northeastern orchards shared the same fate.

From a farming perspective, the climatic trend that helped produce this bumper crop of big, meaty garlic is pretty clear: Over the last 15 or more years, our garlic has been emerging and maturing earlier than it used to, though not as precociously as this season. On average, the last spring frost in our region is occurring a couple of weeks earlier than it did when I started farming in 1987, and the first frost in the fall is coming a week or two later, which means our growing season is getting extended at both ends. In January, for the first time in more than 50 years, the USDA came out with a revised Plant Hardiness Zone Map that reflects the warmer temperatures and longer growing season in many parts of the country. (The Plant Hardiness Zone map is based on average minimum temperatures and is a fair indicator of which plants can be profitably grown in different parts of the country.) Our farm officially moved from Zone 5 to Zone 6 (though I didn’t really need the USDA to tell me that.)

Vegetables are not the only living things to register this warming trend. We’ve noticed a shift in the arrival dates of some migratory birds. Barn swallows, for example, are showing up sooner in the spring (which means the barn windows have to be opened a few weeks earlier so the birds can gain entry to their nesting quarters inside). Because I like the swallows so much and appreciate their appetite for mosquitoes and other small insects, I keep a record of their arrival date on my calendar. Killdeer, also migrants from the south, are establishing their minimalist nests in our fields in early March, unless there is still snow on the ground. This year I actually saw one of these plover-like birds scouting out the terrain on February 21—that would have been unheard of 20 years ago.

The arrival dates and reproductive cycles of many insects and plant diseases also appear to be occurring earlier, though these are more challenging to monitor. It must be a fascinating time to be a phenologist (one who studies the seasonal cycles of plants and animals in relation to climate).

There’s so much new stuff going on. Earlier bird migrations, changing insect schedules, more frost-free days in the growing season—what’s to complain about? Most of us are not going to say “no” to a longer growing season or the advanced arrival of our feathered friends.

Other parts of the country, though, are not faring as well. Many will remember 2012 for its searing heat and drought. In July, U.S. Secretary of Agriculture Tom Vilsack declared natural disaster areas, due to heat and drought, in 26 states and more than 1,000 counties, totaling about half the land area of the contiguous United States—the largest natural disaster area ever declared in this country. Literally thousands of high temperature records were shattered and scarcely a drop of rain fell during the critical early growing season. If you were trying to grow crops or raise animals anywhere in this vast chunk of real estate, or simply get through the day without air conditioning, you would have been severely challenged, if not totally undone.

Depending on which side of the fence you’re on, this warming trend and its accompanying extremes of weather may be viewed merely as curve balls thrown by a random and fickle Mother Nature. Some folks subscribe to a second theory: that the changing weather patterns can be attributed to “global tilt”—a shift in the earth’s axis in relation to the sun. We might, they say, be on the wrong side of a 100,000-year cycle. Or you might suspect, as I do, that our new weather has something to do with the 30+ billon tons of carbon dioxide and other heat-trapping gases we humans send into the atmosphere every year, creating what used to be called a greenhouse effect. (As one who owns a greenhouse and spends a fair bit of time in it, this explanation rings a bell. Even on a cold day in January, so long as the sun is shining overhead, the temperature inside our greenhouse can be a relatively balmy 60 to 70 degrees, without any additional artificial heat. The sun’s rays enter the house and a good portion of the warmth they generate remains trapped inside by two layers of polyethylene film. The result is a welcome buildup of heat on a winter’s day. Carbon dioxide in the atmosphere, I understand, functions a bit like polyethylene film.)

No doubt, the debate over what is causing the earth to get hotter will continue so long as there is money to spend and there are business interests involved. The inevitable cold day or even cool summer that comes along once in a while will only muddy the waters. It’s difficult, if not impossible, to attribute any single weather event to the works of man. It is just possible that all three explanations for the planet’s rising temperatures and erratic and increasingly catastrophic weather—random events, global tilt and global warming—have a measure of validity. A couple of things are pretty certain, however: We can’t do much to influence random climatic changes, and, at this point in time, it seems unlikely that we’ll be able to re-adjust the earth’s axial tilt. That leaves us with the third theory, the one that 98 percent of the world’s scientists subscribe to and the one over which we could have a major influence.

But, back to our farm and its bumper crop of garlic. We spent the first half of July hand pulling mature bulbs after loosening the soil around them with a tractor-drawn cultivator. It was hot and sweaty work. I estimate the total harvest, with leafy tops included, weighed more than six tons.

In the second half of July, we wrapped the plants with bailing twine, 12 or 15 to a cluster, and hung them in our well-ventilated barn and other outbuildings. The goal was to have the tops dry down until there is no moisture left in them, at which point it is safe to cut them off and store the bulbs in mesh sacks or open crates. When cured in this manner and kept in a cool, dry place, our garlic can stay good for nine months or more.

Regardless of what’s going on with the weather and the reasons for it, in 2012 we were dealt a winning hand and raked in a nice pot—one with the distinctly sweet smell of the stinking rose. It’s true—the season is not over. There are more vegetables to plant and harvest, more markets to attend and, if recent history is any guide, there will be more freaky weather to survive. Right now, as I head for the bank, I feel some empathy for the many farmers elsewhere who drew bad cards this summer. It must have been exceedingly painful for them to watch their crops frizzle in the sun and their expenses pile up well beyond any income. I’m keeping my fingers crossed, hoping that I won’t be joining their ranks down the road a bit.