How Warm Winters Make Plants Think It's Spring (and Why It Matters)

On Christmas Day, the daffodils in my mother’s front garden were poking their green heads from the soil. This would be one thing if my parents didn’t live in Connecticut—but they live in Connecticut, where there should have been a whole “White Christmas” thing happening. Instead, the ground was soft and wet, and the air felt and smelled a lot more like late March than December.

It's possible that El Niño is responsible for this—or climate change is, or maybe it's simply a “warm winter." But it's clear (to farmers and to laypeople like me) that this winter has been a lot warmer, a lot stranger in general than usual on the East Coast. New York City’s first snow of the season came January 17; the day prior had been unseasonably warm, temperatures climbing to the low 50s.

“When I think about a changing climate,” Jack Algiere, the farm director at Stone Barns told me, “it's not that this place is getting warmer—but we're getting harsher, stranger storms at moments in the year when we don't usually have harsh conditions.”

The fear for some farmers is not that it’s getting warmer here overall, but rather that the weather patterns are changing entirely. Farmers can plan for steady weather; they can even plan for steadily surprising weather. (“I grew up in New England, so I'm used to strange winters,” Jack said—and besides, farmers are careful to plant seeds that are adapted to the specific region.) It’s when a stretch of surprisingly warm weather comes in December, or it’s cold and icy in April, that the farmers begin to get nervous. “I think this year in particular was warm, and is something of a sign of our future—and a sign of the things that are changing in our climate.”

In the past few years, there have been more storms—both more unexpected and unexpectedly harsh. Last year, snow blanketed the Northeast well into March, and then the spring was long and slow. Ultimately, this was a good thing for a lot of crops: A long, late spring meant that trees were in blossom for a longer amount of time and therefore bore more fruit. But the amount of snow, and the severity of it, was surprising. And this year, shortly after Christmas, “It got super-cold really fast. That's a shock to the plants' systems, and some took a real hit,” said Jack.

When I asked one farmer at the Union Square Greenmarket if the warm weather was affecting his season, he told me abruptly, “Yeah. We have more stuff.” Warmer weather has meant that farmers can keep crops like kale and brussels sprouts in the ground, keep harvesting, keep bringing things to market—and that’s a good thing, financially, for these farmers, for whom the summer is a boon and winter is slightly scrappier. In winter, produce farmers rely on selling through the produce they keep in cold storage (like apples, potatoes, cabbages, and beets) or other resources, like eggs, meat, or dairy products that rely less strictly on the seasons.

If it were a “typical” winter—one with average temperature and weather patterns, farms honestly wouldn’t look that different to the eye (save, maybe, for a blanket of snow). “We plan for winter growing,” Jack, who’s been farming for 20 years and started the farm at Stone Barns in 2003, told me. “We still have about a half-dozen crops in the field,” he said—spinach, broccoli, cabbage, artichokes, kale, brussels sprouts. “We'd be doing that even if it were really cold, though the snow would slow us down. The warm weather, in a way, makes it easier to do that.”

But it also makes it easier for other things besides desirable crops to grow, like pathogens, weeds, and mildew. Jack and his team have had to be especially watchful for mildew, which can destroy plants, growing in the greenhouses. “It's so warm in there,” he said. “The plants [in the greenhouses] are all adapted for cold weather, but we had 75-degree weather in the last week of December. The fact that there’s low [winter] light helps, but the warm temperatures trick the plants. They don’t have enough light or energy to do the work” of growing fully.

“Today it feels like winter... The ground is hard. We may still get a dormant period, which is really important,” said Jack. Most plants need a certain dormancy period in order to grow and produce properly; this dormancy looks different for many plants, but in the Northeast, they tend to need a stretch of increased darkness and for the ground to be cold—or even to have a layer of snow over the ground. This coldness kills bacteria in the soil and allows the plants to “rest,” and while the plants have the same amount of darkness as they would any other year at this time, the soil has been warm and soft, essentially tricking the plants into thinking it’s springtime.

So how are farmers protecting themselves? How are they dealing? The weather has encouraged Jack to be thinking about the kinds of plants he grows, and specifically, to look for a wide, diverse range of adaptive plants that can handle major fluctuations in temperature. It also has him thinking about “fringe crops”: “We usually don't grow apricots here, because the frosts come late and zap them,” but he had great apricots this year. “It could very well be the same ways with almonds and figs,” he ventured.

“Fringe crops” are ones that will occasionally bear fruit and sometimes won't. It’s not usually practical to put all of your proverbial eggs in a basket like that, but having a few crops that do well at more extreme ends of the weather spectrum can save you in a tough period when nothing else is growing (or just not growing well). “When you have a lot of diversity on the farm, some years are good for some things and some years are good for other things,” said Jack, citing the need for increased diversity on farms, at Stone Barns and everywhere. “Growing just one or a couple of similar things can be totally wiped out by a weather pattern. That can be really destructive for a farmer.”

For this reason, specialty crops—and specialized farms—are more at risk in unpredictable weather. At the greenmarket, I talked to Clara, a woman bundled up behind the Roxbury Mountain Maple stand. She told me about how maple trees, like other plants, need a cold stretch; cold allows for sap to develop in the tree. Without a cold snap, the flavor of the syrup could change, or the sap could run dry too soon—bad news for maple syrup lovers, and farmers.

It’s something Gary Scheft, a garlic farmer in Norfolk, Connecticut, has considered, too: Heirloom garlic is all he grows. Gary trusts his seeds to produce beautiful German white hardneck garlic, his preferred variety; and he trusts the manure, which his friend’s cows produce, that he spreads on his fields.

“But by now, the ground should be frozen,” he said; German white hardneck garlic loves cold weather, and benefits from having a layer of snow over it. But this year, things have sprouted. "Too much sprouting," he tells me, "would mean that the plant thinks it’s springtime," only to literally be nipped in the bud were a cold snap to come.

For Jack, the director at Stone Barns, “The only way [the weather] affected my planning is that we could get just about anything.” He saw plants and trees—dandelions, forsythia, cherry trees—flowering in December, and while a freeze probably won’t kill the plants, it might “make the bloom in the spring not function,” he said. That is, the plant may only have a few buds rather than a whole tree of them; fewer buds means fewer blooms, which means less pollination, which means less fruit.

Jack also reminded that weather isn’t the only thing that influences a growing season: He does a lot of his planning and planting with consideration to moon cycles, and by watching what’s happening elsewhere on the farm: which birds are migrating in and out, which plants are beginning to sprout, how warm the soil is. “We can't be married to a particular date,” he said of planting. “We have to be reading the ecosystem. With vegetables, there's luckily a lot of room for flow. We can cooperate with what the weather gives us.”

Have you noticed any changes in your own gardens? Have you talked to farmers about it? Tell us in the comments.