You can beat the blahs of a winter landscape by remembering the three B’s of off-season gardening: blooms, branches, and berries. Admittedly, there are only a handful of introduced plants, and even fewer native species, which bloom and provide colorful relief during the gray days of mid-winter, with the striking and noteworthy exception of witch hazel (Hamamelis virginiana), alternately called common, fall- or winter-blooming witch hazel.

Our native variety is a relatively slow-growing small tree or upright shrub which begins its horticultural display in autumn with yellow fall foliage which soon turns to orange and golden-brown, and proudly heralds the beginning of its late-season blooming period. After the leaves have fallen, clusters of small, soft-scented yellow flowers appear along the branches from October through December. Each spidery clump consists of four twisted, fringe-like petals not quite one-inch long. Interestingly, the lemon-yellow ribbons tend to fully unfurl on warm sunny days, when we are lucky enough to get them, and, like most of us, curl up into a more compact mass when the weather turns cold and threatening.

More than a dozen non-native witch hazel cultivars have been gaining in popularity among winter gardeners, with dramatic new flower colors ranging from ruby-red and copper, to burgundy and bright orange-yellow, and featuring significantly later blooming periods, even into February, and a stronger fragrance. These low-maintenance hybrids are typically crosses of Chinese and Japanese witch hazels, and include favorites like ‘Jelena,’ which combines brilliant fall foliage in November with an encore of coppery red blooms as late as February and March, and ‘Arnold Promise,’ a brilliant yellow late-blooming cultivar developed by the Arnold Arboretum.

For more year-round color, garden designers have long cherished the subtle and sometimes spectacular twigs and trunks of our native dogwood species. Leading the list is red osier dogwood (Cornus sericea formerly stolonifera), also aptly called red-twig dogwood. This fast-growing specimen is a cousin to the white flowering dogwood with which we are more familiar, and quickly forms attractive thickets ideal for screening or habitat plantings.

Although its white flowers and berries are popular among songbirds like vireos, finch, and pine warblers, they are somewhat dull in appearance, a deficit more than offset by its brilliant red twigs and reddish-green bark. After a snowfall, nothing stands out in a winter garden more than the vivid red stems which seem to shoot up from a pure field of snow. In addition, goldfinches have been known to favor this species for a nesting site; their bright feathers flitting among the branches will ornament both shrub and garden alike.

Another attractive option is the yellow-twig dogwood (‘Silver and Gold’), a cultivar of red osier, renowned for its green and white variegated foliage, good autumn color, and, above all, bright golden bark.

Silky dogwood (Cornus amomum) takes its name from the grayish hairs along younger branches and flower buds, and features reddish-purple twigs and darker mahogany-brown bark. Silky dogwood also presents lovely flat creamy-white clusters of flowers in the spring, followed by bluish clusters of fruit in late summer, often lasting through fall and possibly winter.

The final and perhaps most important components for a winter garden are berries. Berry-bearing small trees and shrubs add a surprising splash of color and seem to stand out equally well against either snow-covered garden beds or leaden winter skies. Of equal importance, berries support scores of migrating and over-wintering birds, some of which, like cardinals, woodpeckers and bluebirds, add their own element of lively color to a landscape.

Topping most lists is winterberry or “possum haw” (Ilex verticillata), a deciduous native holly with upright, spreading stems reaching up to ten feet in height. Clusters of white flowers appear in April through May, producing bright reddish-orange to deep red berries which last through the winter, avian appetites notwithstanding. Keep in mind that winterberry is dioecious, having male and female flowers on respective plants, and requiring at least one male shrub for every three to four female specimens.

Native viburnum species, such as Arrowwood or American cranberry (V. trilobum), provide attractive clusters of white flowers in spring, brilliant fall foliage, and berries ranging from bright red to bluish-black in fall through winter. The species also provide an important source of fruit to more than fifty species of songbirds in our area.

Both red and purple chokeberries (Aronia species) take their name from colorful fruits which offer brilliant red and scarlet foliage in autumn, followed by bright red or blackish-purple fruits throughout the winter. For best effect, it is generally recommended that chokeberries be planted in clusters for a natural, sprawling effect.

Sumacs are best known alongside roadways, but smooth sumac (Rhus glabra) makes for attractive massed plantings or “colonies” in home landscapes, like the chokeberries. Autumn foliar displays, similar to chokeberries, are replaced in winter by greenish-crimson fruit which can last into spring and are keen favorites of bluebirds, catbirds, robins, and mockingbirds.

These, of course, are only a sampling of the (mostly) native species which can be used to adorn a winter garden. There are also evergreens with variegated foliage, ornamental grasses featuring golden orange stems and graceful tufts of seedheads, and so much more. For an expanded tour of the subject turn to Rosemary Verey’s now-classic The Garden in Winter.

Copyright 2012, Joseph M. Keyser

Celebrating the Roots (& Tubers) of Our Thanksgiving Traditions

Thanksgiving is fast approaching, a holiday full of swirling memories and preparations, like so many colorful autumn leaves. It’s a celebration of family and food and delightful traditions. And it can be a reminder that our traditions are actually anything but traditional.

I was rather young when I first learned that my family’s traditional Thanksgiving dinner was not the universal norm. We dined on turkey and stuffing, potatoes, gravy, sweet potatoes, cranberries, and pumpkin pie. Normal enough. However, elsewhere in the colonies, specifically Brooklyn, our Italian neighbors celebrated with their traditional Thanksgiving lasagna and antipasto platter.

Later, my wife and in-laws introduced me to the traditional Baltimore side dish of sauerkraut. Curiously, the denizens of Charm City have somehow failed to draw the logical connection between sauerkraut and hot dogs at ball games, but that’s another story.

For the most part, we imagine Thanksgiving as a timeless tableau, a generous feast first celebrated by grateful Pilgrims and kind-spirited Native Americans at the Plymouth Colony in 1641. And we generally envision an assortment of foods similar to our “traditional” Thursday spread, sauerkraut notwithstanding.

Alas, we are savoring more of myth than reality. The first Thanksgiving observance actually took place in Newfoundland, Canada, in 1578, almost 50 years before Plymouth. And when the Separatists of Plymouth finally did celebrate their “First Thanksgiving,” it was more likely held near the end of July a couple years later.

Don’t worry, however, there was undoubtedly a harvest celebration in 1621, and we can always trace our tradition to that event. But don’t expect any mashed potatoes or cranberry sauce.
Written accounts from the period indicate that such feasts included venison, mussels, cod, and herring. What, no turkey? It is possible that wild turkey (the game bird, not the bourbon) was served, although duck, goose and crane were more likely.

Bad news concerning sweet potatoes: Christopher Columbus may have brought the colorful tuber back to Europe in the late 15th century, but in 1621 no one in New England was enjoying baked sweet potatoes drizzled with maple syrup. Likewise for potatoes, the world’s favorite root crop. Boiled, baked, or mashed, the noble spud would not appear on New World tables for another 100 years or more. Fortunately, Native Americans had introduced the settlers to pumpkins and to numerous varieties of squash.

And while cranberry sauce may not have been available, as sugar was not to be had, the Native Americans would have had cranberries on hand. In fact, they often mixed the berries into their traditional travel food, pemmican, sort of a cross between beef jerky and granola bars. Moreover, it has been suggested that Indians may have taught the colonists to tame the tartness of the berry by boiling it along with maple syrup, which may have been the inspiration for cranberry sauce itself.

The colorful cranberry has almost as important a role in American agriculture as it does on the dinner table. Cranberry, along with the Concord grape and the blueberry, is one of the few native fruits commercially grown.

The plant’s name is traced to Crane-berry in the early 17th century, either because cranes were noted gobbling their way through the cranberry bogs, or, more colorfully, because the vine’s discrete pink flowers in spring resemble the head and bill of a Sandhill crane, or the scarlet lores (patch) above the crane’s eye.

Today, while cranberries are grown throughout North America, nearly half the total harvest originates in the bogs of Massachusetts. It seems to be a tradition that lives on.

And while the lowly potato is a relative newcomer to our traditional feast, its journey to our table was as difficult and tenuous as airport, train, and highway traffic the night before Thanksgiving.

Potatoes (Solanum tuberosum) were brought back to the “Old Country” some 50 years after Columbus made landfall. Like the tomato, it is another South and Central American member of the Solanacaea or deadly “Nightshade” family. And, like the tomato, potatoes were considered to contain aphrodisiac properties, on the one hand, or cause leprosy -- which was also associated with unbridled carnal activity. There are varied accounts of potatoes returning to the new world in the Virginia colonies as early as the 1630s, or to New England via Irish immigrants in the early 18th century.

More recently, in developed countries, 99 percent of all root crop production is in potatoes. And why not? They are famously high in fiber, carbohydrates, and protein, as well as vitamins B and C, and essential minerals such as magnesium, zinc, iron, and copper.

For the most part, they are relatively easy to grow, with hundreds of cultivars available, perfect for raised beds or even containers and tubs. For the adventurous gardener, russet or white potatoes might be all well and good, but what about the dazzling array of heirloom varieties, ranging from ‘Yellow Finn’ and ‘German Yellow,’ to red-skinned ‘Pontiac’ and ‘Red Norland,’ or even ‘All Blue’ and ‘Purple Peruvian?’ After all, what could be more traditional than old-fashioned heirloom varieties?

Sweet potatoes introduce another tradition: the annual confusion between sweet potatoes and yams. For the record, the so-called “true yams” (Dioscorea spp.) are actually of West African or Asian origin, and they are dry, white, and quite starchy – unlike the sweeter, delectable flesh of sweet potatoes with their deep yellow or reddish-orange tubers.

Sweet potato (Ipomoea batatus) is related to bindweed or morning glory, as its fast-growing vines will attest, and originated in Central or South America, possibly Brazil, Peru, or Equador.

There are generally two types of sweet potato, a dry-fleshed variety with white flesh, best grown in colder climates (and far too yam-like for comfort), and the moist-flesh or southern variety with which we’re happily familiar. Interestingly, the majority of sweet potatoes are grown in China, while it’s the second most important crop in Japan, where it is used to produce starch, wine, and alcohol. At home, nearly 30 percent of the sweet potatoes grown in the U.S. are cultivated in North Carolina, which also goes a long way to explain the South’s fondness for sweet potato, rather than pumpkin, pie.

Sweet potatoes can be rather versatile in the home garden. They can be cultivated normally, like potatoes, or even used as either an attractive ground cover, or interspersed in hanging baskets with trailing flowers. No promises, but the vines also infrequently produce pink flowers. In addition, by way of warning, I once surprised myself to find about two pounds of tubers growing in a hanging basket one fall season. I had only planted the vines to provide a light green contrast to other, darker foliage, little expecting a side dish.

You can start your sweet potato plantation by simply buying “slips” from local nurseries and garden centers, or through catalogs, for more unusual cultivars. About 25 slips will suffice for a family of four. You can also propagate your own from tubers which you or a neighbor have successfully overwintered from the garden. Don’t try to use store-bought tubers, as they are frequently treated with a compound precisely to prevent sprouting. Set your sweet potato in a glass of water, with one-third submerged. When the young sprouts are about six inches long pull them off (don’t cut them) and set them in water or moist sand until a dense mat of roots are formed. You can transplant them outdoors a few weeks after the last threat of frost. And, by the way, sprouting sweet potatoes is great fun for younger children. Many a school windowsill is covered with vines every spring.

For home composting devotees, note that sweet potatoes can be easily grown in a modest-sized bin filled with shredded leaves from the previous autumn. Be sure to keep the leaf mold moist for the first several weeks while roots are developing. By the following fall, your leaves will have mostly decomposed into a wonderful mulch, and your tubers will have grown freely and exuberantly in their fluffy medium.

Overall, sweet potato vines can grow up to four feet or more, although there are several cultivars with compact growth habits and shorter vines, which are ideally suited for barrels or patio containers, including ‘Bunch Porto Rico’ and ‘Vardaman.’

Other popular standard varieties include ‘Allgold’, ‘Heart-o-gold,’ ‘Nancy Hall,’ ‘Centennial,’ high-yielding ‘Beauregard,’ ‘Jewel,’ ‘Yellow Jersey,’ and ‘Southern Delight.’

And while sweet potatoes are an important part of our Thanksgiving tradition, they are gaining even more status as an important source of nutrition, with fiber, vitamins A and C, iron and calcium, antioxidants, and beta carotene. In fact, one sweet potato provides half the recommended daily allowance of beta carotene. It’s everything you need for a happy – and healthy – holiday. Just watch out for those tiny marshmallows!

Copyright 2012, Joseph M. Keyser

Going Solar to Set Your Soil Straight

Everybody knows that sunlight makes plants grow. But did you know that solar energy can help you “grow” healthier soil? If not, welcome to the solar-powered world of soil solarization!

Solarization is a safe, non-chemical, and effective method for controlling the host of pests and diseases which might be lurking in your garden soil -- harmful bacteria, fungi, and nematodes, as well as insect eggs, root-gnawing larvae, and weed seeds.

Of course, most of your landscape gets along just fine without special intervention, but for vegetable gardeners and folks with specialized garden beds, such as dahlia collections or an annual cutting garden, going solar can help prevent problems, while enhancing any site’s horticultural performance.

Solarization is a creative spin on the greenhouse effect, which uses simple plastic sheeting and the sun’s radiant energy to help sanitize the top six to eight inches of garden soil. And although the process does require setting aside a garden area for about two months during the summer, it is far safer and less expensive than using toxic soil pesticides or other fumigation methods.

Experienced gardeners know that they should rotate their vegetable crops each year and select disease-resistant varieties to control soil-borne diseases. However, this is not always a practical option for some gardeners with limited space, and after a while, any soil used and planted repeatedly with similar crops will be still be infested with damaging populations of the most persistent pathogens, like verticillium and fusarium wilt, as well as parasitic nematodes, along with other weed and pest problems.

By using solarization to dramatically elevate soil temperatures up to 140 degrees for a period of weeks, you can essentially bake those problems away. Moreover, solarized soil is rapidly re-colonized by beneficial bacteria and fungi, such as those which help fix nitrogen in the soil, while yet other beneficial microorganisms will fill the void to help fight off pathogens in the future. In short, your soil will be healthier and better able to enhance plant growth and crop yields.

To begin, select a garden bed or planting area at least 30 to 36-inches wide, which is normally the most practical width for planting. Smaller strips probably will not generate or retain enough heat to be effective.

Remove all visible vegetation and other plant debris, and then cultivate the soil to a depth of six inches or more. It is generally preferable to use a rototiller to break up any clumps and provide a smooth, friable medium. Keeping the texture of the soil smooth is essential to prevent the formation of air pockets which will interfere with heat generation and conduction. Also, carefully rake over the surface of the planting area to ensure that it is completely free of stones or other coarse materials which might tear or puncture the plastic sheeting.

During cultivation, be sure to add any desired organic amendments such as compost, or any fertilizer or lime, which might have been called for by a soil test. If you are planning to use soaker hoses or drip irrigation, you should put those elements in place now. Please note that after solarization, you do not want to till or disturb the soil, as that will only expose buried weed seeds. Finish by digging a trench approximately six to eight inches deep and wide around the perimeter of your garden bed.

Next, water the planting area thoroughly. Use a sprinkler or soaker hose system and let it soak the prepared soil for at least several hours, penetrating almost to a depth of one foot. Every square inch of soil must be moistened for adequate heat generation.

Afterwards, cover the area with a clear plastic sheet made from UV-stabilized or resistant polyethylene or PVC. Untreated plastic film will degrade in sunlight, and neither black nor opaque plastic will generate sufficient heat.

Selecting the proper thickness of plastic tarp is important. While very thin film (.5-1 mil) is less expensive, it tends to rip very easily, and would only be suitable for one use. Thicker plastic (4-6 mil) is tougher and lasts longer, but does not allow as much more sunlight to pass through. Instead, try to find a medium sheet (1-3 mils), and stretch the plastic tight and smooth across the planting surface.

In addition, for increased effectiveness, consider using a double-layer of plastic with an insulating air space between the layers. You can easily separate the two layers using empty aluminum cans. The extra layer can increase soil temperatures by another six degrees, while also retaining more heat on overcast days and at night.

After getting your plastic firmly in place and tucked down into your trench, backfill with soil to bury the ends of the sheet – and just wait for the sun to do the rest. If your solarized bed is in an especially windy location, you might want to place some bricks or rocks on top of the trenched area as an additional anchor.

For the most part, solarization should be undertaken anytime during the hottest, brightest months, from June through August. It can be done earlier or later, but additional time under wraps would be required, up to three months. Traditional summertime treatment requires four to six weeks, and as much as eight, if the skies were particularly cloudy, or if you have been plagued with stubborn, noxious weeds for years.

After solarizing, carefully remove and store the plastic for another use in a subsequent year. You garden bed is now ready for planting. If you do not plan to plant for several months, with a cool weather crop, for example, be sure to cover the bed with a weed-free mulch.
Lastly, remember that solarization only eliminates or reduces pest organisms and weed seed from the top several inches of soil. Do not disturb your sanitized soil any more than is necessary to slip in your new plants.

Copyright 2012, Joseph M. Keyser

Dwarf Citrus Trees: Big On Flavor & Fragrance

During the cold, gray days of winter, few things brighten and warm a room like the sweet, rich aroma of lemon blossoms or the glow of maturing oranges among glossy, green leaves. Thanks to the widespread cultivation of dwarf citrus trees, any gardener with a bright window can enjoy all the sensory pleasures of lemons, limes, oranges, and more, all year long.

Like most fruit tree cultivation, where a branch or scion of a desirable variety of tree is grafted onto a sturdy rootstock, dwarf citrus trees are grafts of a normal fruit-bearing branch onto dwarf rootstock, which keeps the plant at a manageable size for summer patios and year-round enjoyment in your solarium.

Because the fruiting branch is from a full-sized tree, the fruits which develop are also full-size, and full-flavored. However, that also means that like a dutiful orchard manager, you will have to prune your tree periodically to keep it within bounds. Normally, pinching off growing tips will help maintain an attractive shape, which is preferable to letting the plant send out tall shoots requiring severe pruning.

In addition, always remove shoots or “suckers” which tend to pop out from the dwarf rootstock. Look for a diagonal scar running the trunk’s circumference around about six inches above the soil surface. Snip off any shoots below the graft union as those pesky shoots will sap energy from the desired plant, and produce, if at all, inconsequential or tasteless fruits.

The majority of dwarf citrus used as container or houseplants tend to grow between four and six feet tall, and do best in pots ranging from 12 to 16 inches in diameter, although some popular cultivars can be grown in containers as small as eight inches.

In milder climates, dwarf trees can reach up to nine to 12 feet when grown in halved whiskey barrels or redwood tubs. Around here, though, citrus must be taken indoors before any danger of frost, and most of us would rather not lug a several hundred pound giant into a standard family room.

To keep your dwarf citrus in check, you will actually borrow some techniques from the world of bonsai. Root pruning is usually required every three years or so, which will control overall growth, while also allowing you to replenish soil and soil nutrients. Without root pruning, you will have to continually repot your specimen until it becomes a behemoth.

To begin, carefully remove the plant from its pot and use a sharp knife or pruning shears (or even a pruning saw) to trim off several inches of root from around the sides and bottom of the root ball. Use a standard container soil mix to replace and reposition the plant at its previous height in the pot.

Incidentally, root pruning is often traumatic for many novices, who are more comfortable with watering and feeding their plants. But fear not, eventually everyone gets used to it, and your tree will continue to thrive and flourish for many years, possibly even dozens or more.

Ongoing care for your dwarf citrus requires plenty of bright light and even exposure. Be sure to slowly rotate containers every week or so. After all, no one likes a lopsided lemon tree.

Dwarf citrus prefer evenly moist soil. Do not allow the soil to completely dry out, and do not waterlog the soil or allow the plant to sit in standing water. Many practitioners consider an inexpensive moisture meter indispensable and as important as a good pair of pruning shears. Plan to water a bit more frequently than you might with other houseplants, perhaps every three to four days, especially during warm, dry weather.

Note that citrus are heavy feeders, especially as frequent watering will leach out water-soluble nutrients like nitrogen. It is recommended to use a fertilizer with a ratios two to three times higher in nitrogen than potassium and phosphorous (an N-P-K of 3-1-1). Be sure to use a complete fertilizer periodically to replenish essential micronutrients.

Of course, the most important element in dwarf citrus cultivation is selecting a plant that will intoxicate you with its fragrance and tickle your taste buds.

The choices are delicious in their own right, ranging from typical naval oranges, tangerines, lemons, true limes and grapefruits, to a host of hybrids with special characteristics. For the most part, growers have selected varieties specifically for container and indoor use which will do well in relatively cool environments. You do not have to replicate Floridian heat to achieve sweet and luscious fruit.

Among oranges, some of the most readily available and favored are Trovita, with a thin skin, which is equally prized for juice or eating. Satsuma oranges, sometimes considered a mandarine, like Valencia, are smaller, with an easy-to-peel fruit and a truly intoxicating aroma from spring-borne blooms which last up to a full month.

And while oranges might be the first citrus variety you are considering, spare a thought for the lemon tree. While most citrus bloom in the spring and produce fruit the following winter (or later), lemons actually bloom throughout the year, providing four seasons of fragrance, and year-round fruit. The most popular varieties include Lisbon, Eureka and Meyer, the latter of which is thought to be a cross between a sour orange and a lemon, and is perhaps the most popular variety of all thanks to its somewhat sweeter, slightly tangerine flavor.

Limes aren’t only for margaritas and gin-and-tonics! In addition to favorites like Bearss Seedless, one of the most intriguing offerings is Kaffir (or Thai) lime. In addition to tangy juice and a zesty zest, the glossy, dark green leaves of this variety can be chopped or julienned and used much like lemon-grass in Thai and other related Indonesian cuisine.

And while grapefruit are available, why not explore the exciting world of hybrids. For example, consider the increasingly popular Minneola Tangelos, or Honeybell, a cross between tangerines and grapefruit. This juicy, bell-shaped find offers a bright, reddish-orange skin, easily peeled like its tangerine ancestor, and sharing both a tartness and intense tangerine flavor.

Clearly, while these varied citrus trees may be dwarf in size, the selection, flavors, fragrance, and rewards of raising them are truly enormous.

Copyright 2012, Joseph M. Keyser

Cleaning Your Home of Biological Pollutants

Be it ever so humble, there's no place as deadly as home. Well, that's not strictly true, even though most accidents occur in the home, including most auto accidents taking place within five miles of home sweet home. What a deathtrap! But seriously, the fact is that most of us still spend a considerable part of every day indoors. Safely tucked away in the family room or kitchen, few of us realize that we are being exposed to a host of potentially harmful biological pollutants, which in varying cases can cause mild discomfort, often confused with a simple lingering cold, or more severe illnesses with long-range health complications.

Looking around our homes, it might be hard to imagine that our pets, humidifiers, and carpeting can represent sources for biological contamination. In fact, for most people a damp towel or face cloth or a soggy bath mat produces nothing more than a sour smell, and
"contamination" is an extreme way of viewing that spot of unsightly mildew in the shower stall. However, many other individuals are highly susceptible to these pollutants, including the elderly, young children, pregnant women, and people with respiratory problems such as
asthma, chronic allergies, and lung disease. For this at-risk community, biological pollutants deserve both attention and corrective action.

Contributors to contamination

Many of the causes of biological pollution are hard to avoid, even in the cleanest homes, and include everyday activities like cooking and showering, which result in the high moisture levels conducive to the spread and growth of mold, mildew, dust mites, and other unwanted guests, all of which can, in turn, lead to health complications. In fact, the "moisture connection" is one of the most widespread causes for contamination, although it is one of the easiest to remedy.

Among the other common sources are pollen, infectious agents like bacteria and viruses, microscopic dust mites living on household dust, cat saliva and other pet dander -- the tiny or microscopic scales from skin, hair and fur, and feathers. Macroscopic and generally hated agents include mice and rats, especially their protein-rich urine, and numerous insect pests. Cockroaches are bad enough, but even microscopic "flakes" from their dead bodies can cause significant distress for some people.

Allergists and respiratory specialists generally look at several major categories of health problems related to biological pollution, including allergic, infectious, and toxic reactions, although many are interrelated, especially as conditions favorable to one problem are advantageous to others, particularly where moisture, warmth, and humidity are involved.

An allergy is basically the immune system's response to an unwanted foreign substance or allergen, such as pollen or pet dander. In sensitive individuals, this response goes well beyond sniffling and sneezing and can take the form of a severe and even life-threatening overreaction. Upon entering the body, allergens prompt the body's immune system to produce millions of antibodies which attach themselves to cells throughout the body, ready and waiting for another "invasion" by that specific substance. When the allergen is detected, the antibodies trigger the cells to release chemicals called histamines to help destroy the allergens, although the allergic reaction can often pose more of a health threat than the allergen itself.

Infectious reactions or diseases are the handiwork of bacteria and viruses, and are easily spread via contaminated countertops, improperly cleaned cooking utensils, and through the air from person to person. Bacteria and viruses can also be brought into the home from the outdoors on dirty shoes or soiled clothing, or even by bringing plants inside from a garden or patio. Airborne diseases, which can also be spread via some ventilation systems, have also demonstrated a much higher viability in moist environments where they can survive until meeting up with a new host -- or victim.

Toxic reactions have started to receive a great deal more attention as discussions mount regarding sick building syndrome. Among the best known example is humidifier fever, brought about by toxins released by microorganisms and fungi thriving in poorly maintained or designed heating and cooling systems, both in large commercial properties and in some typical residential systems and home humidifier units.

Drying Out

While increased cleanliness, better cleaning habits, and air filters can help control some of the particulate contaminants in the home, there is no doubt that water and moisture play perhaps the most significant role in creating biological pollution. Standing or stagnant water, or water-damaged materials (wood, wallboard, carpeting or carpet pads) are breeding grounds for insects, bacteria, and other pests. Cold exterior wall surfaces, especially inside closets or behind furniture and bookcases, can experience condensation, thereby triggering fungal outbreaks of mold and mildew, along with their attendant allergens and toxins. And warm, moist conditions are ideal for dust mites, which represent a one of the most ubiquitous and potent allergens in most homes.

Unfortunately, this "muggy" indoor environment is fairly much the norm in the northern part of the U.S., where studies cited by the American Lung Association found that approximately 30-50 percent of all homes and large structures demonstrate a high relative humidity -- exceeding 50 percent. In addition, research found other signs of periodic dampness in these homes, often resulting from seasonal flooding, leaks, and so on.

Making Your Home Healthier

To prevent the rash of problems likely to result in a tropical household, the Environmental Protection Agency recommends that relative humidity be controlled to 30-50 percent, and that remedial steps be taken to better manage other sources of moisture. The following is a room-by-room recipe for a healthier home.

Basement: If carpeting is used on a concrete floor, install a vapor barrier (basically a plastic sheeting) to keep moisture from entering the carpet backing and fibers. Clean and dry water-damaged carpets within one day -- or consider replacing the carpet. Also, it might be advisable to simply use another flooring surface or removable area rugs. Check for and repair any sources of leaks or water damage, especially around windows and exterior stairwells. Increase air circulation and consider using a dehumidifier in damp sublevels, and be sure to frequently drain (every day) and clean the "evaporation tray" or collection reservoir.

Kitchen: Install and use an exhaust fan -- or at least open a window -- when cooking, hand-washing dishes, or using a dishwasher, etc., to vent moisture to the outdoors. Do not rely on the all-too-common rangetop hoods which simply filter cooking particulates. Periodically check, empty, and thoroughly clean refrigerator drip pans; check for moldy gaskets and clean or replace them. Carefully clean all food preparation areas and utensils. However, exercise caution when using various cleaning products; do not mix different types of cleaning agents. Consider using an effective organic or botanically-derived alternative. Clean and rinse sponges and frequently change dish towels since disease pathogens are sometimes spread by cleaning with contaminated cleaning aids; use a different sponge for each different cleaning chore. Clean all damp surfaces in the kitchen.

Utility Room: Vent dryers and consider using an exhaust fan when washing laundry. "Air dry" wet laundry outdoors.

Bathrooms: Use an exhaust fan to vent moisture or open a window. Replace and clean towels and bathmats regularly. Clean and dry surface areas thoroughly; use the same amount care as with kitchen sanitation, especially since many bathroom cleaners contain caustic chemicals and release harmful vapors. Remove, vigorously clean, or replace moldy shower or window curtains.

Bedrooms: Individuals with a low tolerance for dust and dander should avoid down-filled pillows and comforters, and should use allergenic-proof mattress pads, as well as foam rubber and other synthetic bedding materials. Further, bedclothes should be frequently laundered with hot water reaching 130 degrees or more.

Attics and Crawl Spaces: Check areas for leaks or water damage, provide exterior venting and improve air circulation. Cover the dirt "flooring" of crawl spaces under the house with a vapor barrier to keep out moisture and control pest infiltration.

General Household: Improve overall air circulation by ensuring that fresh air can enter the house via air exchangers or by opening windows; move furniture away from exterior walls; and leave doors into rooms partially open most of the time, including closet doors -- paying special attention to closets with exterior walls. Remove all traces of mold through cleaning; do not simply paint or wallpaper over damaged areas. Change or clean air filters for heating and cooling systems regularly, including window air conditioners, whose evaporation trays should also be examined and cleaned periodically. If a central humidifier is being used, carefully observe the recommended maintenance schedule; with portable units, change water as directed and clean all water-contact surfaces. Dusting and vacuuming can be torture for sensitive individuals, as the act of cleaning often stirs up a universe of mite allergens and other contaminants. Highly allergic people should leave areas (or homes) being cleaned; others should wear a protective mask, and use a dampened cloth or sponge-mop for cleaning. Vacuum and dust often to remove surface dust and reduce dust mite habitat. A central vacuum system is advisable for the acutely sensitive, although rather costly. Other extreme measures can include replacing wall-to-wall carpeting with washable area rugs and replace window blinds or delicate shades with washable curtains.

Copyright 2012, Joseph M. Keyser