I’ve said it before and Yogi Berra said it before me, “It ain’t over till it’s over.” A recent night’s temperature plummeting to 15°F. was still not enough to put the brakes on the vegetable garden. Arugula, mâche, kale, and spinach are looking as perky as ever and, most important, taste better than ever. Lettuce is surviving, not exactly perky though.

It’s a wonder that these tender, succulent leaves tolerate such temperatures. You’d think the liquid in their cells would freeze and burst the contents to smithereens. That would have been the case if the 15° night temperature had come on suddenly, without any precedents.

Plants aren’t passive players in the garden. Increasingly cold weather and shortening days acclimated these plants to cold. They move water in and out of their cells, as needed, to avoid freezing injury. And increasing concentrations of dissolved minerals and sugars in the cells make the water freeze at lower temperatures. Perhaps that’s one reason why these vegetables taste so good.

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One whole bed in the garden is very lush green, even growing a little. That bed is home to endive that’s covered with a floating row cover fabric and then clear plastic, both held above the plants by low, metal hoops.

Interestingly, temperatures I’ve measured within the endive tunnels are not that different -- actually, not different at all -- from temperatures I’ve measured outdoors. But something’s different. The increased humidity under the tunnels is probably at least partially responsible for the fresh taste and appearance of the endive. The tunnels also slow down swings in temperature, giving plants time to move water in and out of their cells and whatever else they do preparing for and recovering from cold.

Too many people, even gardeners(!), consider endive as nothing more than a bitter, green leaf best used as garnish. Reconsider. Given close spacing so that inner leaves of each head blanche from low light along with cool and cold temperatures, and endive takes on a wonderful, rich flavor. Only the slightest hint of bitterness remains, enough to make the taste more lively -- delicious in salads, soups, and sandwiches.

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Man can’t live on greens alone. But I still have no need to go to a store to round out my vegetable fare. Much of what grew in last season’s garden is in storage, on tap for when I need it. Besides the usual frozen green beans, corn, okra, and edamame, steamed, cooled with a fan, then packed into freezer bags, and the usual canned tomatoes, a lot of vegetables are in cool storage.

That cool storage could have been my refrigerator, except that no refrigerator is spacious enough for a winter’s worth of turnips, winter radishes, beets, and leeks, and a few heads of cabbage. A couple of years ago I built a walk-in cooler. Saving money and energy, I cool this cooler with CoolBot (www.storeitcold.com), a nifty device that tricks a window type air conditioner in believing it has not reached its pre-set minimum temperature of 60°F. I set the indicator on my CoolBot to 40°F., and there it stays. I also have some boxes of apples and pears in there, as well as, up to a couple of weeks ago, pawpaws.

As temperatures continue to drop outdoors, the CoolBot will no longer be needed. Then I’ll move all the boxes to my unheated mudroom. As temperatures drop even more, the boxes will go down into my basement, the temperature of which should by then have dropped into the 40s.

It’s amazing, if you sleuth around your house with a thermometer, especially a house built more than 50 years ago, how many different temperature zones you find. Below 40°F but above freezing is ideal for most fruits and vegetables, except for tropical fruits, sweet potatoes, and winter squashes, which like slightly warmer temperatures.