Most garden plants need about an inch of water a week, which comes out to a three-quarter of a gallon per square foot. You can give that water in one shot, once a week, or in small doses, say one-seventh of an inch each day. For the benefit of your plants, you’ve got to be consistent in whatever watering schedule you choose. Of course, who’s going to remember to go out every single day to give all their plants just a little water? Hence the traditional recommendation to water deeply and infrequently.

Enter “drip irrigation,” an automated method of delivering water to plants in small doses. Small doses of water promote shallow rooting, so you may wonder what the advantage of drip irrigation is. Well, shallow rooting is beneficial because most of the feeder roots of plants live near the surface of the soil. Why? Because that is where nutrients, air, and biological activity are most concentrated.

Drip irrigation also uses water very efficiently. When you flood the soil once a week around a plant using a sprinkler or watering can, you fill up all the soil pores. But plant roots need air to function, so do not begin to drink up any water until gravity drains enough water out of the soil to leave some air spaces. Then, the plant draws on water still clinging to soil particles by capillary attraction. But that first water that drained away was wasted. Drip irrigation supplies water gradually, the way plants drink it up, with roots always working at their best because the soil never need be flooded.

TIMED CONVENIENCE

One of the most important components of my drip irrigation system is a water timer, which automatically waters my garden every day through the summer. The timer is inexpensive, operates on a battery, and threads right onto my hose spigot. I set the timer to turn the water on six times a day, but for only a few minutes each time, just long enough to deliver a total of one-seventh of an inch of water each day.

Before the water makes its way out to my garden, it also passes through three other items attached to the timer. These items are: a backflow preventer, which keeps water running in one direction only (to prevent siphoning in case of a pressure drop); a filter; and a pressure regulator. Drip irrigation operates at low pressure, so inexpensive, low pressure fittings can be used and minimal demands are made on household water.

OUT TO THE GARDEN

The water is carried out to, and through, my garden in half-inch, black plastic pipe, which can be buried if desired. Once out in the garden, water is dripped to plants via “emitters” that plug into this tubing. Wherever I have a continuous row of plants—carrots or other vegetable plants, for example—I plug in a special tube that drips out water at closely spaced intervals along its length, then run that emitter tube along the row of plants. For my blueberry shrubs, each spaced seven feet apart, I run the half-inch pipe along the row of plants, then plug in a couple of individual spot emitters next to each plant.

These emitters, whether tube or spot emitters, are more than just leaky pieces of plastic. The best of them are technological marvels that consistently put out a specified amount of water even if water pressure changes. They also have little flaps or channels for swirling water around and preventing the tiny orifices from becoming clogged with any debris that might enter the line. Most emitters can be buried, but mine are on the surface of the ground so I can periodically check up on them.

If you can now picture in your mind your garden watered by drip irrigation, you might also “see,” in that picture, some other advantages of this system. Fewer weeds, for example. Drip irrigation puts water precisely where you want it, so you’re not promoting weeds and wasting water on paths or bare soil, both unavoidable with a sprinkler. And because plant foliage remains dry with drip irrigation, chances for diseases are minimized.

Rain rarely falls as soon as a plant needs water, so even in a wet summer, plants grow better with timely watering. And in a dry summer -- well, the effect of watering is dramatically obvious. My corn, which grows eight-foot-high stalks even in dry years, is testimonial to the benefits of drip irrigation.

Lee Reich, PhD (leereich.com) is a garden and orchard consultant; he hosts workshops at his New Paltz farmden, which is a test site for innovative techniques in soil care, pruning, and growing fruits and vegetables.

by Lee Reich 

Black currant fruits are “of a stinking and somewhat loathing savour, the leaves also are not without the stinking smell,” wrote herbalist John Gerard in his famous Herball over 350 years ago. I disagree. I relish this fruit. And as far as the smell–no, the aroma–of the leaves: I think it makes pruning black currant bushes or even brushing up against them a heavenly experience.

Odd that Mr. Gerard should write so venomously against the plant. Of many people that have smelled black currant leaves in my garden, no one has given the rich, resinous aroma anything but praise. The leaves even have been and are used to make a tea, both for their flavor and medicinal properties. The fruit was just coming into cultivation in Gerard’s time, and in the 350 years since publication of the Herball, Europeans have grown exceedingly fond of the fruit. Usually, the fruits are cooked up into a delectable jam or squeezed to make a rich-tasting juice (Ribena is a well-known British brand). In the Bordeaux region of France, black currant fruits are made into the liqueur cassis.

It’s not only for the taste that northern Europeans (and I) enjoy black currants. The fruit is extremely high in vitamin C, and even before vitamins were known, the fruits were called “quinsy berries” for their soothing effect on sore throats.

So how come hardly anyone here in the U.S. grows black currants? The reason traces back to the end of the 19th century, when a disease called white pine blister rust hitchhiked into this country on some pine trees from Ireland. The fungus that causes white pine blister rust needs two different host plants–a white pine and a susceptible Ribes, a genus that includes gooseberries and currants–to survive. To keep this disease from threatening the valuable white pine timber crop, the federal government decided to ban the planting of Ribes.

The ban’s effectiveness was limited, though, because of the many wild Ribes in our woods, and the great distances that disease spores could travel. And anyway, most cultivated gooseberries and currants are resistant to the disease. So the federal ban was lifted in 1966 and put under state mandate. Nonetheless, while the federal ban was in place, two generations of Americans forgot about how good gooseberries and currants tasted.

Black currant is the most susceptible of all cultivated Ribes to white pine blister rust. But thanks to Canadian fruit breeders in the 1960s, a few rust-immune varieties–Consort, Crusader, and Coronet–were developed. Since then, a number of better-tasting rust-immune or rust-resistant varieties have been identified, varieties such as Titania, Belaruskaja, and Kirovchanka.

In addition to good fruit and pleasant aroma, black currants have other qualities to recommend their planting. Deer evidently concur with Mr. Gerard about the aroma, because they rarely nibble the plants. Mice agree: In a winter, when they girdled many plants beneath the snow line, only my black currant plants were left consistently untouched. Insects, diseases, even birds, similarly keep their distance.

The only care the plants need is pruning. One year old stems bear best, so all that’s needed is to each winter cut to the ground stems that are going into their second year.

Black currant is a quietly handsome bush. No visually notable flowers adorn the stems nor do the leaves light up with fall color at the other end of the season. But all season long, beginning early in spring and continuing well into fall, the bush is attractively clothed in lush, forest-green leaves. As an edible specimen shrub, give black currant six feet of elbow room all around; as an edible hedge, set black currant plants three feet apart. No need to choose a site in full sun, as required by most other fruits, because black currant will grow and fruit well in sun or part shade.

There is only one thing that you should not expect from a black currant bush, and that is “black currants” such as are sold dried in boxes in the markets. Those are dried ‘Black Corinth’ grapes, a small grape dried and shipped for centuries from a Greek port of that name. Those raisins came to be called bastarde corinthes and corans on their way to being called “currants.”

Black currants are so delectable and easy to grow that they warranted a whole chapter in my book Uncommon Fruits for Every Garden, available, among other places, at leereich.com/books/uncommon-fruits-for-every-garden. 

Lee Reich, PhD (leereich.com) is a garden and orchard consultant; he hosts workshops at his New Paltz farmden, which is a test site for innovative techniques in soil care, pruning, and growing fruits and vegetables.

by Lee Reich   

The traditional vegetable garden is a one-dimensional affair, with rows of individual vegetables separated by plenty of bare ground. That layout worked fine when most backyards measured in acres rather than square feet.

Today’s vegetable gardens are smaller than those of yesteryear but can give us a lot more bang for the buck in terms of space used and energy expended. We can reap more from less space by “thinking outside of the box” and beyond, with multidimensional vegetable gardening.

Dimension #2

A second dimension is added to a garden when it is planted in beds rather than individual rows. Those wide spaces between rows in traditional plantings were not for plants, but to allow room for walking while planting, weeding, hoeing, or tilling. The permanent beds of my vegetable garden are each 36 inches wide, allowing easy reach into them from the 18-inch-wide paths. 

Within a bed, plants can be grown close enough together so that their leaves eventually touch. Up a bed I might plant two rows of cabbage, three rows of lettuce, or five rows of carrots or onions. I plant onions four inches apart in the row and reap over fifty pounds of three- to four- inch-diameter orbs from a mere 10-foot-long bed!

Dimension #3

“Grow up” is what I tell some of the vegetables, and when they do, a third dimension is added to the growing space. Grown on a trellis or stake, peas, cucumbers, melons, tomatoes, and other vining plants can be planted closer together to yield more food per square foot of planted ground. As added benefits, staked vegetables get better air flow, which prevents disease, and stay more free of dirt and of nibbles from slugs and other ground-dwelling creatures. 

Some trailing plants reach out for support while others are more ambivalent. Stems of twining plants, such as pole beans, or of plants with tendrils, such as peas and cucumbers, flounder about looking for some support; once they find it, they naturally pull themselves up. Not so for tomato vines. With long stems but no means for clinging, tomato plants are as happy to crawl over the ground as to climb a stake, so they need to be tied or otherwise helped up. 

Dimension #4

The fourth dimension in my garden is time. One way to make use of time is to commingle vegetables with different maturities together in a bed. Interplanting a bed of broccoli and lettuce plants provides a good example. Two lettuce plants spaced eight inches apart can live between broccoli plants spaced two feet apart. The lettuce is harvested and out of the way by the time the broccoli finally fills the bed.

No need to restrict interplanting to just two different vegetables at a time. Run a long row of spring radishes up the center of that same bed of broccoli and lettuce (or just squeeze it in short rows here and there) for three interplants. The radishes are harvested and out of the way before the lettuces fill in, and the lettuces are out of the way before the broccolis fill in.

Few vegetables are in the ground from the very beginning to the very end of the growing season, so time can also be used to slip two, even three, different vegetables into the same piece of ground in succession in one season. For instance, tomato plants cannot go into the ground until the weather warms, so why not plant and harvest a crop of spinach, which thrives in cool weather, ahead of the tomatoes? Bush beans that peter out by midsummer can be followed by cabbage.

Dimension #5

And now for the fifth dimension: Putting time where it is not, tricks meant to add days or weeks to the beginning and/or end of the growing season. Pre-sprouting seeds in moist paper towels lets the ground outdoors warm or be used for a few extra days until the seeds sprout. Making use of transplants is another way to cheat time. Lettuce is a good example of a vegetable that can yield abundantly this way. Sown in containers from midsummer on, lettuces can be transplanted wherever space becomes available, such as where spent bush beans or corn plants have been cleared away, or onions harvested. Cabbage, broccoli, endive, and Chinese cabbage take longer to mature than lettuce, but transplants can similarly be slipped into the garden at the beginning or end of the season. 

Another way to add days or weeks to the growing season is to hasten warming of the soil in spring. Dry soil warms up faster than wet soil, making raised beds, with their good drainage and increased exposure, ready for planting earlier in spring. Pulling back any mulch, which insulates the ground, also hastens soil warming. Mounding the soil into south-facing ridges likewise speeds warming, in this case by capturing the sun’s rays more squarely.

Warming the air is another way to make time where it was not. The traditional glass bell jars—cloches—have been superseded by plastic bell jars, water-filled tubes (Walls o’ Water), fiberglass A-frames, floating row covers, and plastic tunnels held aloft by a series of metal or plastic hoops anchored in place with their ends poked into the soil. All these methods add weeks to the growing season.

Trying to fill every available niche of physical space and time in the vegetable garden is like doing a multi-dimensional jigsaw puzzle. “Nothing puzzles me more than time and space; and yet nothing troubles me less, as I never think of them,” wrote Charles Lamb 200 years ago. I do think of them. But if frustrated trying to integrate every “puzzle” piece into every square inch of garden, I just go ahead and plant.

Lee Reich, PhD (leereich.com) is a garden and orchard consultant; he hosts workshops at his New Paltz farmden, which is a test site for innovative techniques in soil care, pruning, and growing fruits and vegetables.

by Lee Reich    

Smokey Ritual

I wonder if my neighbors suspect that I’m engaging in some sort of occult ritual as I take occasional winter rounds around the farmden followed by puffs of grey smoke. Perhaps I’m entreating tiny gnomes living within the soil to keep weeds at bay next season? Or begging garden gremlins to make my soil fertile? No, and again no! I’m merely spreading wood ashes on the vegetable gardens, the lawn, beneath fruit trees and bushes—everywhere, in fact.

I must be careful with my terminology: I’m not disposing of wood ashes; I’m enriching my soil with wood ashes. Wood ash is a rich source of potassium, a nutrient required by plants in amounts second only to nitrogen. Potassium helps build strong stems and helps plants resist disease. Potassium also regulates the opening and closing of stomates, the tiny pores in leaves through which leaves “breathe” out oxygen and “breathe” in carbon dioxide for photosynthesis.

Put the Ash in a Pot and You’ve Got…

The close connection between potassium and wood ash is reflected in a traditional source of, and root of the word, potassium—”potash.” The easiest way to obtain potassium compounds used to be to leach them out from wood ashes using water in iron pots—the first step in homemade soap, among other uses. Go to a nursery and ask for a potash fertilizer, and you will be handed a bag of potassium sulfate (sulfate of potash), potassium chloride (muriate of potash), greensand (a mined mineral that offers micronutrients in addition to potassium), or—if it was a century ago— wood ash. “Potash” technically means potassium oxide but sometimes also refers to potassium carbonate or hydroxide.

Wood ash contains from one to about ten percent potash. Ashes from hardwood trees are at the top of this range and softwood ashes are at the low end. I store my ashes in a metal pail under cover of the garage to prevent rain from washing much of the nutriment out of the  ashes. 

Since “potash” is technically potassium oxide, which includes the weights of both potassium and oxygen, raw potassium concentration is always less than the potash concentration. Seventeen percent less, to be precise. The archaic designation equating potassium with potassium oxide remains because otherwise fertilizer buyers would feel gypped. When buying a bag of 10-10-10 fertilizer, the 3 numbers are generally taken to mean percentages of nitrogen (N), phosphorus (P), and potassium (K, from the latin, kalium). As a fertilizer salesperson, you’d have to go through the whole explanation of why your customer is getting 10-10-8.3, but it’s the same as the previous, not quite correctly stated, 10-10-10.

Exactitude Not Required

I’m not overly precise in my spreading of these ashes. I start at one end of the farmden in the beginning of the wood heating season, then work my way across the farmden, aiming to spread no more than five to ten pounds of ashes over every hundred square feet. Eventually, lawn, vegetable gardens, fruit trees and bushes get their annual dose of potash (not only from wood ash; there’s also plenty of potash in compost, and leaf and wood chip mulches).

Wood ash is good stuff, but is not to be overused. Plants need adequate, not excessive, potassium. Too much potassium upsets the balance of other nutrients in a plant. Wood ashes also make the soil more alkaline, so they never get spread in my blueberry temple. Wood ash is best kept away from rhododendrons, azaleas, pin oak, mountain laurel, and other plants that enjoy very acidic soils.

I do not dump—whoops, spread—all my wood ashes around the farmden. I save a little for use in potting soils, mixed in at the rate of a quarter of a cup per gallon of mix (except in potting mixes destined for acid-loving plants, of course).

And Something for Pests

And some I sift then save to use in the garden during the summer for pest control. Plants sprinkled with dry ashes become unpalatable to rabbits, bean beetles, and onion and cabbage maggots. A thick line of dry ashes on the soil becomes a Maginot Line against slugs, until washed away by rain. The alkalinity that washes into the soil from wood ashes spread over the ground kills cutworms. 

Cucumber beetles are repelled (or killed?) by a spray made from a handful each of wood ash and hydrated lime mixed into two gallons of water, then sprayed on the leaves. Squash bugs are repelled by a sprinkling of wood ashes mixed with turpentine, at the rate of one tablespoon turpentine per gallon of wood ash. And a paste of wood ashes and water on the trunk of a peach tree will keep borers at bay.

Squash bugs have never been a serious problem in my garden and my cabbages rarely get maggots, so I can’t personally vouch for all these pest deterring and killing properties of wood ashes. But wood ashes are nontoxic and the above suggestions come from reputable sources, so the treatments are worth a try when needed. The main drawback to using wood ashes for pest control is that they usually must be applied again following rain. Also, keep wood ashes off tender seedlings, or they will be burned.

Perhaps there is some sort of gnome or gremlin in these ashes that impart them with such a myriad of uses.

Lee Reich, PhD is a garden and orchard consultant; he hosts workshops at his New Paltz farmden, which is a test site for innovative techniques in soil care, pruning, and growing fruits and vegetables. leereich.com.

Lee's beloved Dymo-Mite Tapewriter labeler. Photo by Lee Reich.

by Lee Reich   

The Well-Dressed, Young Tree

My young trees are now decked out in all their winter finery—arboreal attire, perfumes, and cosmetics that will protect them through the winter. Insects and disease-causing fungi are dead or dormant, but larger, furrier animals now pose a threat. Deer, rabbits, and mice are eager to gnaw on succulent stems, bark, and roots.

And then there’s cold weather to dry out or sunscald the trees. Evergreens are most susceptible to drying out because they lose water through their leaves all winter long. Sunscald, caused by fluctuations in bark temperature, is most likely to occur on the southwest facing bark because that’s where it’s last heated by day before the sun—and temperatures—plummet.

With their thick, tough bark and gnarly, old wood, older trees are better able to fend off animals and cold than young trees. So here’s what my well-accoutered, young trees are wearing to protect them from winter’s woes.

For “footwear,” mulch is all the rage. Leaves, hay, and straw insulate the soil against low temperatures as well as from wide swings in temperature. Evergreens are especially thankful for mulch because it keeps more soil water unfrozen and, hence, accessible to roots during the winter. Never pile mulch right up against any tree trunks, though, or else the trunks may rot and mice not only will have sheltered living quarters, but also bark on which to nibble right at home.

Which brings us to a choice of tree furnishings for keeping animals at bay. Down around a tree’s “ankle,” a legging of 1/4-inch hardware cloth, an eighteen-inch-long cylinder pushed a bit into the ground, prevents mice and rabbits from gnawing at roots and bark near the base of the tree. Higher up in the tree, “perfume” fends off deer. For starters, I’ll dangle a bar of deodorant soap in the branches—one bar per tree, the cheaper the better. In the past, I’ve also used mesh bags containing wads of human hair but my deer, at least, don’t seem to mind that perfume anymore. The efficacy of any perfume in keeping deer away depends on how many and how hungry the deer are, and how easy it is for them to get to neighbor’s trees instead.

Moving on to the condiment department of winter tree wear, we find sprays that make trees taste bad to furry animals. Because these animals are vegetarians, many of these sprays are based on animal products such as eggs or milk. These animals also don’t like hot pepper. Commercial sprays are appropriately named: ‘Deer-Away,’ ‘Chew-Not,’ ‘Hinder.’ The main problem with these sprays is that they wear off over time, so spraying must be repeated periodically through the winter, especially since animal feeding gets worse as winter wears on. Some, such as ‘Deer Stopper,’ have a gummy base that, although making spraying more difficult, keeps the material on the plant for weeks. Once again, the efficacy of such sprays depends on how many and how hungry the deer are, and what else is readily available to eat.

All well-dressed, young trees should have some “makeup” on their trunks. A coat of white latex paint protects the bark from sunscald, reflecting sunlight so that the bark does not heat up during the day. Paper or plastic tree wraps are sold that serve the same purpose. I added bone meal to the paint that I used last winter, as a friend had suggested that rabbits and mice, being vegetarians, would not gnaw on boney-tasting bark. They didn’t.

Besides the above trappings, a few other measures also avert winter animal damage. Mark your calendar next year to give your lawn a through mowing at the end of the season in order to give the searching eyes of owls and hawks a better look at scurrying mice. Cats and dogs also help in keeping furry pilferers at bay.

Final decor for trees this season is lights. These are not functional, but Christmassy.

Identifying Trees in Winter

Trying to identify leafless trees this time of year is a nice game to play alone or with a companion as you walk about enjoying the brisk winter air. (I did say “leafless”—identifying evergreen trees quickly becomes too easy.) Such a game also forces a close look at the more subtle details of plants and in so doing enhances appreciation of these plants even now when they are stripped of leaves and flowers.

Of course, this is hardly a game with some trees. Everyone recognizes paper birch by its peeling, white bark. Watch out, though, grey birch has similar bark. Catalpa tree is quickly identified by its long, brown pods. And pin oak by its growth habit: lower branches droop downward, mid-level branches are horizontal, and upper branches turn upward.

Most deciduous trees don’t have such obvious signatures this time of year. Then, what is needed is an observant eye and a good book to describe trees in words and pictures. Particularly helpful are those books that take you through a logical sequence of steps in identification, such as Fruit Key & Twig Key to Trees and Shrubs by William Harlow and Woody Plants in Winter by E. Core and N. Ammons.

One of the first things I look for when confronted with an unknown, leafless tree is the arrangement of the buds on the young twigs. Are the buds “opposite” (in pairs, on opposite sides of each twig) or “alternate” (single and separated from each other along the length of stem)? It turns out that most deciduous trees around here have alternate buds (and most shrubs have opposite buds). So if I see opposite buds on a tree, the choice immediately is narrowed to maples, ashes, dogwoods, or horse chestnut (though this tree is not as common here)—easy to remember as “MAD Horse.” That still leaves the question of which species of dogwood, maple, or ash.

Other features further narrow the choices within opposite- or alternate-leaved trees. The shape of the buds can be telling. For example, flowering dogwoods have flower buds that look like little buttons capping short stalks. Pawpaw’s buds are rusty brown and fuzzy like velour. Also telling are twig color and nuances in bark. Purple twigs covered with a cloudy coating identify a tree as boxelder, a maple species. American hornbeam has smooth, blue-grey bark with ripples like muscle, which gives it one of its common names, musclewood.

I also look for thorns. If present, the tree is most likely black locust, honey locust (watch out again, though, because most cultivated forms of honeylocust are thornless), hawthorn, or wild plum. Black locust has short thorns, honeylocust has long thorns, often branching, and plum’s thorns are, in fact, short, sharp branches with little buds along their length.

Fruits are another guide. Prickly gumballs hang almost through winter from sweetgum trees. Magnolias still have their fruits, which look like little pineapples with red seeds popping out. And it’s within the rules of the game to look on the ground for help in naming a tree. There, you’ll still find some nuts of the shagbark hickory (identified also by its shaggy bark) and acorns (but there are many oak species, so the trick is to identify which one).

Still at a loss for a tree’s identity? Break off a twig and make a slanting cut to expose the pith. If the pith is chambered, rather than continuous, the tree is either a black walnut or a butternut. Butternut trees have chocolate-brown pith; black walnut trees have toffee-brown pith.

The taste of a twig sometimes is the giveaway. Black cherry tastes like bitter almond, and yellow and river birch taste like wintergreen. Paper birch twigs are tasteless. Slippery elm twigs become mucilaginous when chewed.

This should give an inkling of details that we tend to overlook in spring, summer, and fall. Some of these details are interesting; some have a subtle beauty; and some are useful only for identification.

As far as the identification game, there is one more very useful identifier. Deciduous trees are supposed to be leafless now, but often a few leaves hang on into winter. They will be dead, dry, and twisted, but often still “readable.” Not only that, but oaks and beeches are so reluctant to lose their lower leaves that you can spot these species even at some distance by their skirt of dry leaves.

Lee Reich, PhD is a garden and orchard consultant; he hosts workshops at his New Paltz farmden, which is a test site for innovative techniques in soil care, pruning, and growing fruits and vegetables. Learn more at leereich.com.