I’m prepared, gardenwise, for cold weather. What’s more, I’ll know when it’s here. My quiver of thermometers stands ready.

Outdoors, I’m monitoring temperatures with two Taylor brand thermometers. The “Digital Wireless Weather System” sensor out in the garden beams temperature readings to the indoor receiver unit to keep me posted on the weather. In addition to the temperature, this thermometer shares the dew point and the maximum and minimum temperatures from whenever I last re-set those temperatures.

The other Taylor thermometer, an old, mechanical, mercury-filled, min-max thermometer keeps the digital thermometer honest. What it lacks in convenience (no beaming from this thermometer) it makes up for with accuracy. Good thing, too, because for all its convenience, the digital thermometer is often -- perhaps always, I’ll have to check -- 5 degrees out of whack. Five degrees is a lot when I want to know if frost descended on the garden some early spring night or want to brag honestly about how cold temperatures drop here in midwinter.

My mudroom is unheated but maintains relatively moderate temperatures by sharing a wall with the woodstove-heated living room. As such, it’s something like a giant refrigerator, a good place, certain times of the year to store potted plants, scion wood, and boxes of fruits, vegetables. But how cold, or warm, is it in there? Another old, mechanical, mercury-filled, Taylor min-max thermometer keeps me posted on conditions in there.

My basement is barely heated and has a Bilco door entrance that I re-built out of wood with a clear polycarbonate plastic cover to make a very cool (temperaturely speaking), bright place to overwinter plants. Gotta measure the temperatures there, of course, for the plants and, back from the bright area where I have stored home-made beer and boxes of apples. More thermometers.

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For all the pleasure, in food, fun, and ambience, afforded by a greenhouse, it does bring it share of nail biting.

One cold, winter night, I realized that the propane heater wasn’t kicking on; the gas company had forgotten to fill the tank. Now a weekly reminder pops up on my computer screen every Wednesday morning to remind me to check the gas level and call for a delivery if the level drops too low. Problem solved.

A bevy of thermometers --and that's not all of them?

On another cold, winter night, I again realized that the propane heater wasn’t kicking on when needed; this time the tank was full but the pilot light was out. Strong winds had created an updraft in the chimney, snuffing out the flame. A couple of holes drilled low on the pipe let some air into it to decrease the updraft. Problem solved.

On yet another cold, winter night, I realized yet again that the propane heater wasn’t kicking on when needed; again, the tank was full and the pilot light was out, but this time it refused to be lit. The fault then was with the thermocouple, which turns off the gas if the pilot light goes out. I purchased a new thermocouple -- and 3 more backups for future malfunctions -- and soon a warm, tropical breeze was flowing from the heater.

As further insurance for gas problems, I installed an electric space heater wired to its own thermostat. The electric heater should take care of any gas problems unless outdoor temperatures drop into the single digits, which would be more cold than the heater could handle.

All the above precautions are for naught if the electricity fails -- not a rare occurrence around here. The propane heater’s thermostat and fan gobble up a miniscule amount of electricity; miniscule though it is, the heater will not work at all without it. Got that covered now, with a deep discharge marine battery on a trickle charge that is wired to an inverter to convert the direct current to house current. 

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Even the electrical backup is for naught if I’m not aware that the gas is low, the thermocouple needs replacement, the gas heater isn’t working, or the electricity is off. Enter the newest addition to my quiver of thermometers: the “La Crosse Technology Wireless Temperature Station with Trends and Alerts.” This thermometer wirelessly beams the greenhouse temperature homeward. 

Even better, this thermometer will wail if the temperature drops below (or above) a certain amount, which I set at 32°F. in the greenhouse. Of course, I can check the honesty of that thermometer against yet another old mechanical, mercury-filled, Taylor min-max thermometer that hangs in the greenhouse on a post with the La Crosse sensor. The La Crosse thermometer is new; so far it’s honest.

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Not to place too much emphasis on temperature (did I mention my compost thermometer, with its 2-foot-long probe sunk deep in the innards of one pile, or the small probe thermometer that monitors temperature within a seedling flat?) but temperature is not the end-all for how plants fare in winter.

Temperature trends are important, as are temperature and moisture conditions going into winter. For instance, Asian persimmons grow in South Korea but not here; our winter temperatures are similar but the dry autumn weather of South Korea toughens plants up for the cold months ahead. My bamboo, Phyllostachys aureosulcata, came through last winter, when temperatures dipped briefly to -20°F., looking spry and lush. Single digit temperatures of the recent polar vortex burned all the leaves.

With my thermometers, I may not be able to do anything about the weather (outside the greenhouse). But at least I can complain about it with authority.

Help!

For a little experiment I'm doing I need seeds of Thompson & Morgan's 'Gardener's Delight' tomato. This British company (http://www.thompson-morgan.com) sells those seeds on their British website, but not their U.S. website. T&M does not ship items from that site to the U.S. Can someone out there send me a packet of those seeds? ('Gardener's Delight' seeds are also sold by some U.S. seed companies but, for the purposes of my experiment, I need T&M's seed of that variety.) Please contact me through my website, which is linked to this blog (on your right, just below the photo of me). Thanks.

One of my favorite things about our planet is that the darkest and the coldest days don’t coincide. Wouldn’t that be depressing if they did? We cleared the hump for the darkest days back at the end of December but days and nights are, on average, scheduled to still grow colder and colder.

For me, the longer days offset the increasing cold. Only partially, though, because November to March brings the most overcast days here in the northeast. The days, at least, are growing longer and longer by about a minute each day early this month to over two minutes from one day to the next by the end of the month.

It is at the end of this month that we plunge, on average, into our greatest depth of cold. My tack for making the most of cold weather is to enjoy it, by skiing and skating. And by going into my greenhouse. Inside, on sunny days, it’s a steaming, humid tropical retreat even if temperatures are in the ‘teens on the other side of the inflated double walls of plastic.

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I don’t get it, the undue attraction for baby leaves of lettuce, arugula, and other greens for fresh salads. Truman Capote said that the rich are not like you and me; they eat smaller vegetables. Perhaps, deep down, eating tiny vegetables makes us feel rich.

Not me. Right now, I’m thoroughly enjoying mature heads of fully grown Romaine and Buttercrunch lettuce picked fresh within a hour of being put into a salad bowl. The leaves are crunchy, sweet, and, in the case of Buttercrunch, also buttery. That’s the luxury of a home greenhouse, in addition to the virtual trip to the tropics it offers.

Not that getting those heads of lettuce -- as well as kale, chard, parsley, celery, mâche, claytonia, and arugula -- from the winter greenhouse takes no effort. Planning is perhaps the hardest part. The greenhouse

 might be tropical on a sunny day but light inside is the same as outdoors, except less because it needs to go through 2 layers of plastic film. Low light and, to a lesser extent, cool temperatures on nights and overcast days (the heater kicks on at 36°F.) make for little growth in the greenhouse in the dead of winter. My goal, then, is to fill the 400 square feet of space with plants that are just about large enough to harvest by early December.

A home greenhouse does feel luxurious.  So as not to be profligate, I eke everything I can from the space. In-ground fig trees there bear abundantly from August to October, then their leaves drop and they get pruned back, so they cast no shade in winter. On the benches I raise all my vegetable and flower seedlings. And melons and cucumbers sometimes trail on the ground beneath the figs all through summer. All this for only $680 per season, averaged over the past 11 years, as well as my labor (of love).

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  So how much sunlight does shine within my greenhouse, or into the sunny, south facing windows of my home? Not much this time of year.

Let’s quantify the light. One measure of light is the foot-candle (fc), which is the amount of light cast on a square foot area by a candle at one foot distance. You can get an estimate of this measure using a digital SLR camera. Set it on aperture priority with the aperture at f/8 and the ISO at 100. Hold a white sheet of paper so whatever light you're measuring falls directly on it and measure the shutter speed reading the camera gives you (without a flash, obviously) for a good picture from about a foot away. Multiply the shutter speed times 4 for the approximate foot-candles.

(Shutter speed is usually expressed as a fraction of a second, so a speed of “500” is really 1/500th of a second; for foot-candles, you’d multiply 500 times 4 for 2,000 foot-candles. If light is very dim, the shutter speed might be more than a second; no need to measure, in this case, because in such light any plant will barely stay alive.) 

I recently took a few measurements. Outside, on a slightly overcast day, I measured 2,000 fc. Measurements were 1,000 fc righ right at a south-facing window and in the greenhouse, and 500 fc four feet back from the window. Light at a north facing window measured 100 fc, and beneath a 27 watt fluorescent table lamp, 60 fc.

A bright summer day bathes our beautiful planet with 10,000 fc of sunlight. No wonder plants indoors and out are just biding their time. Not to mention the cold.

Hardy Kiwifruits, Better Than the Fuzzies

Last week I wrote that, what with the cold weather and low-hanging sun showing its face but briefly each day, there’s little for a gardener to do now. That proved not strictly true. Soon after I wrote those words, I received a holiday card from David Jackson and Holly Laubach of Kiwi Berry Organics, growers of what I can attest to are, as it said on the card, the “World’s Sweetest Kiwi.” Theirs are hardy kiwifruits, the small, cold-hardy cousins of the fuzzy kiwis you usually see in the market; with their smooth skins, you pop them into your mouth like grapes.

Most importantly, David and Holly’s card sported a photo, a snowy scene of their kiwi plants pruned to perfection, the fruiting canes all neatly arching over with their ends tied down to their supporting wires. To

David and Holly's kiwis

me, the scene was both beautiful and inspirational. Acting on inspiration, I headed outdoors, pruners in hand, to get to work on my own kiwi vines.

In past years, I delayed all pruning until after the coldest part of winter. Accepted wisdom is that later pruning reduces chances for winter injury. Last year, David told me he started pruning his vines in autumn after leaves dropped. I followed suit warily with one or two vines and they came through winter unscathed. Perhaps it’s our warmer winters of late, perhaps damage that occurs depends on the plant species, or perhaps the accepted wisdom is wrong. At any rate, I’m now pruning with abandon.

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Staring at the tangle of stems on my kiwi plants could have quelled my enthusiasm had I not been presented with this sight in years past. Kiwis are rampant vines, each year sending out masses  of vigorous (as long as 15 feet!) that twisting stems that are hard, at first, to make sense out of. Pruning is a must to

My kiwis, before pruning

keep the vines manageable and easy to harvest, bathed in sunlight for high quality fruit, and to stimulate an annual flush of new wood. Fruits are borne only near the bases of new shoots growing off one-year-old canes.

My plants, like David’s, are trained on a T-trellis about 6 feet high with 5 parallel wires running from T to T. Each trunk rises to the height of the T and then has been trained to spread into two permanent arms, one growing in either direction along the middle wire. The one-year-old canes, off which fruit is borne, grow perpendicularly to the permanent arms, their ends tied down to the two outermost wires.

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My pruning begins with three easy steps. I cut away any shoots poking up from ground level or out along the trunks below the level of the wires. I shorten all fruiting canes a foot or so beyond the outside wires. And I cut the permanent arms back to where they began growth so that adjacent vines don’t grow into each other.

Then things get more complicated. Too many fruiting canes sprout each year from the permanent arms

My kiwis, last spring, after pruning
(except final shortening)

and from along canes that were left for last year’s fruits. The goal is to remove enough so that those that remain are spaced a foot apart on either side of the permanent arms, favoring those that are pencil-thick and originating either from the permanent arm or near the base of a last or previous year’s cane.

Finally, pruning becomes easy again. All remaining fruiting canes get shortened to 2 feet long and then tied them down to the wires, hopefully as neatly as on Dave’s and Holly’s vines. I will delay these last steps until later in spring.

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I realize that not many people grow hardy kiwi vines. You all should: The vines are ornamental (they were brought here and for decades grown strictly as ornamental vines), and the fruits are

delectable and free of pest problems. Even if you don’t grow hardy kiwi vines, though, the above pruning technique could be useful to you. It can be applied, with slight modification, to grapes, which a lot of people do grow.

The only differences with pruning grapes is that the fruiting arms can be spaced somewhat closer along the permanent arm, 6 to 12 inches apart, and each fruiting arm needs to be shortened to only a couple of buds long, at which point they take on a new name, “fruiting spurs” rather than “fruiting arms.”

Whether for grapes or for hardy kiwi vines, training to a T trellis and annual pruning presents me, in late summer on into fall, with “ceilings” of delicious berries splayed out and ready for easy harvest.

Nothing To Do

If the garden, indoors and out, has no need of my attention at any time of year, it is now. I probably shouldn’t even be writing anything about gardening because pretty much nothing is going on. So I’ll make this brief.

Lack of light, warmth, and/or enough cool temperatures are keeping plants quiescent or dormant. The bonsai weeping fig, the Maid of Orleans jasmine (Jasminum sambac), the rose geranium, and other

Bonsai weeping fig, biding its time, for now

houseplants aren’t waiting for warmth. They’re indoors. These tropical plants never experience true dormancy; they’re quiescent, just sitting and waiting for better growing conditions, in this case more light.

My amaryllis bulbs aren’t waiting for brighter days. They’re now leafless, so can’t see the light anyway. Like the above houseplants, the amaryllis bulbs are now also quiescent, in this case from lack of warmth. Yes, it’s warm in my home, but not in the basement where the potted bulbs have been residing. I’ve brought the first pot of amaryllises upstairs where warmth -- and water, the lack of which also has kept the bulbs purposely quiescent -- can prod the bulb awake.

What about lack of enough cool temperatures to kickstart plants? That’s the case, now, with trees and shrubs outside. These plants are dormant, held back not by lack of warmth or water but by their internal physiology that needs to be switched before they’ll respond to good growing conditions.

No petals will unfold nor buds expand into young shoots until these plants are convinced that winter is over. That recognition comes after the plant experiences a period of cool -- not frigid, temperatures -- in the range of about 30° to 45°F. Winter’s “over” for these plants after about 1,000 total hours of exposure to cool temperatures, although the amount can vary among kinds of plants, even varieties of the same kind of plant. Also, a spell of midwinter warm weather can have the effect of removing hours from the “chilling bank.”

So what’s a gardener to do now? Nothing.

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Okay, not everything green is just biding its time. Some tropical flowers take the opportunity to blossom this time of year, even if the plants might be otherwise quiescent.  Hence, we have holiday poinsettias and Christmas cactii sporting their red, pink, or white blossoms.

Not that poinsettia and Christmas cactus flowers will blossom willy nilly. As with trees and shrubs outdoors, these tropical flowers can be prodded to blossom with certain environmental conditions. They don’t know from cold, except that it damages them, so what they need to flower is a change in photoperiod. For late December blossoming, poinsettia needs 6 weeks of 15-hour-long nights uninterrupted by any light at all. Even a table lamp or a flashlight.

Christmas cactus behaves similarly, with an additional wrinkle. If temperatures are cool, in the 50’s, daylength (or, more properly, nightlength, because it’s the length of dark period to which the plants are responding) is immaterial. Plants will flower. If temperatures are warm, in the 70’s, daylength is similarly immaterial. Plants will NOT flower. With temperatures in the 60’s, plants will flower only after a period of 11-hour-long nights.

After a number of years of annual bloom, my poinsettia died, last summer. I got rid of my Christmas cactus many years ago to prevent its infestation of scale insects from spreading to other houseplants. I’ll eventually replace both but for now, there’s still nothing for me to do, gardenwise.

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One plant that responds to some environmental condition, but I’m not sure what, is my orchid, the botanical mouthful Odontoglossum pulchellum. Every winter, sometime between the end of December and

February, my potted plant sends up thin flower stalks along which sprout white flowers whose thick petals look as if they were carved from wax and from which drifts a delicate fragrance. Blooms persist relentlessly, for weeks. The plants only flower in winter, but I’m not sure what exactly brings on the flowering.

After petals finally fall, the plants can take a rest, so need very little watering. The same goes for poinsettia and Christmas cactus plants. By then, of course, it’s late winter so seeds need to be sown and seedlings transplanted indoors, trees and shrubs need pruning, and there’s plenty of other stuff to do, gardenwise.

Holly Needs Sex

LEE’S UPCOMING LECTURES/WORKSHOPS

•Jan. 9: Minnesota Nursery and Landscape Association, Minneapolis, MN, “Weedless Gardening”, “Luscious Landscaping, with Fruiting Trees, Shrubs, and Vines”

•Jan. 23: Long Island Horticultural Conference, Ronkonkoma, NY, “Pruning Shrubs”

•Jan. 25, Northeast Organic Farming Association of New York, Saratoga Springs, NY, “Growing Figs in Cold Climates”, “Espalier Fruits”

•Feb. 6, Indiana Museum of Art, Indianapolis, IN, “Multi-Dimensional Vegetable Growing”

•Feb. 15, Northeast Organic Farming Association of Vermont, Burlington, VT, 

“Grape Expectations: Everything From Choosing Varieties to Eating the Berries”, “Pruning Fruit Trees, Shrubs, and Vines”

•Feb. 20, Ontario Fruit and Vegetable Convention, Niagara Falls, CA, “Uncommon Fruits with Commercial Potential”

•March 1, Northeast Organic Farming Association of Connecticut, Danbury, CT, "Growing Figs in Cold Climates", "Multi-Dimensional Vegetable Gardening/ Farming"

•March 15, Connecticut Master Gardener Conference, Manchester, CT, “Fruits for Small Gardens”

AND NOW, ON TO HOLLY'S PROBLEMS

The problem is obvious: No sex. No sex, no berries. Oh, did I mention that I’m writing about hollies, my hollies? Now, after a number of years, the plants have grown lush with spiny, forest-green leaves. But no red berries.

A holly berry, like any other fruit, is a mature ovary, which is a home for a seed or seeds. Seeds are what stimulate development of a fruit, but seeds themselves usually can't get started without sex. Sex happens in plants when male pollen lands on the female part of a flower, called the stigma, and then grows a

pollen tube down the style, which is attached to the stigma, to reach and fertilize an egg. The product of successful pollination and fertilization is a seed, the development of which induces the surrounding floral part to swell to become a fruit.

Why all this concern with holly's sex life? After all, I don’t give sex a second thought when growing tomatoes. I plant whatever varieties I want and then reap plenty of swollen ovaries . . . er, fruits . . . as well as, incidentally, seeds.

Holly is special because its pollen is borne on flowers that are strictly male and its eggs are contained within flowers that are strictly female. Each tomato flower, in contrast, is botanically “perfect,” with both male and female parts, so can take care of itself, sexually speaking. Similarly self-sufficient are rose flowers, peach flowers, sunflowers, and the flowers of many other plants.

Holly is not alone in having single sex -- botanically, “imperfect” -- flowers. Many nut trees, for example, share this trait. But holly goes one step further sexually, with whole plants being either male or female, a trait shared by ash and persimmon trees, among others.

The long and the short of it is that I need an all-male holly tree or bush if I’m going to deck my halls with (berried) boughs of holly from my all-female holly tree or bush. A male plant, all leaves and no berries, is not as showy as a female, so it's fortunate that a single male can sire a half-dozen or so females.

Adding to their sex problems, or, rather, our problems with their sex life, hollies are not all that promiscuous. A few different species supply us with berried boughs -- notably American holly, English holly,

My sex-less hollies

and Meserve holly -- but, generally, each keeps fidelity to its own species. (An exception is that English holly can pollinate Meserve holly, which is a hybrid offspring of the English species.) Further compounding hollies' sex problems, some males within a species cannot even adequately pollinate some females within the same species because their bloom times do not overlap.

Breeders have come up with a number of virile male varieties whose genders are obvious from their names: Blue Prince and Blue Boy Meserve hollies, and Jersey Knight American holly are examples. These males, as you might guess, are particularly good mates for the varieties named, respectively, Blue Princess, Blue Girl, and Jersey Princess.

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The hollies that I planted were Meserve hollies. I’m pretty sure that I planted a suitable male for my 5 females, with the male sufficiently close to do their thing with the females. So, why no berries?

One possibility is that my hollies had sex, but that late frosts caused fertilized flowers to abort. But every year? My hollies have never sported berries. One hundred percent frost damage every year is unlikely, and especially so this past spring.

The nursery could have mislabeled their plants. The only way to sex the plants is to peer closely at the small flowers early next May and look for those with male or female flower parts. I’ll do that.

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Sex is no problem for my jasmine (Jasminium officinale) plant; its problem is sexuality. The plant lacks flowers, and flowers are all I ask for from this plant. This plant, commonly known as poet’s jasmine, is supposed to sport oodles of deliciously fragrant, starry, white blossoms about now. (Now that I think of it, perhaps the hollies have never flowered no flowers, no sex, no berries.)

Like amaryllis, Christmas cactus, and many other winter-flowering plants, poet’s jasmine initiates flower buds in response to changing conditions such as exist in late summer and early fall. To whit, shortening days,

My flowerless jasmine

cooler temperatures, and/or, in some regions, drier weather. I’ve tried them all with my poet’s jasmine, and every year about midwinter, buds begin growth on the plant that keep stretching out into lanky, twisting shoots that try to grab onto whatever they can twist around. But no sign of flowers or flower buds.

It’s time to threaten the plant. No flowers this winter and into the compost you go, my little jasmine. (I’ve also tried threatening in previous year, to no avail.) Any suggestions??