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Child And Goat

I’ve heard that one of the theories scientists have put forth to explain the increase in asthma and allergy rates is called the “hygiene hypothesis.” What is the hygiene hypothesis, and how does it work?

Our immune systems were designed to cope with a germy world. Unless you live on a farm, postindustrial life can be relatively sterile. Theoretically, exposure to microbes and parasitic worms early in life matures the immune system, priming it to fight microbes rather than such innocuous things as pollen and dander. According to the hygiene hypothesis, a lack of exposure tips the immune system toward inflammation and allergic tendencies, as does the use of antibiotics in the first year of life. In addition, children born by caesarean section face a higher risk of allergies and asthma, because passage through the birth canal inoculates infants with bacteria that normally populate skin, the upper respiratory tract, guts and other organs. The development of healthy gut bacteria positively shapes the immune system.

Proponents of the hypothesis point out that kids who attend day care early in life, grow up in larger families, or spend time around barnyard animals (or at least dogs) are less likely to develop asthma, hay fever and eczema. Critics of the hygiene hypothesis respond that asthma rates have also soared in recent years among children in cities, who may also be exposed to different kinds of dirt and germs. Other possible factors contributing to higher allergy rates in the United States include increased consumption of junk food, inactivity and obesity.

We can all agree on the benefits of clean drinking water and modern sanitation methods. Meanwhile, here’s how you can expose yourself and your family to reasonable levels of germs: Spend time outdoors. Garden. Play with a dog. Afterward, wash up with plain soap and water. If you already have asthma aggravated by dust mites, reduce symptoms by keeping a clean house and enclosing pillows and mattresses in airtight covers.

Photo by Fotolia/Diana Taliun: Children who keep company with furry friends are less likely to develop asthma and eczema.


How often should I swap out my furnace filter, and which types of furnace filters are best?Change Furnace Filters

A furnace filter removes dust, dander and other large particulates from the air in our homes when either the furnace or central air conditioner is running, as the two systems share common ductwork for air distribution. Particulate buildup reduces a filter’s effectiveness and makes the fan work harder, shortening its life span. Both the furnace and air conditioner will operate less efficiently and may require more frequent servicing if the filter is too clogged.

The frequency at which you should change your furnace filter depends on the number of people who live in the home; how many furry pets reside indoors; the presence of smoke from tobacco, woodstoves or other sources; how dusty the environment is; the type of furnace filter; and the thickness of the filter.

If you have multiple fur-shedding pets, you live along a dusty road, or several smokers live in the residence, count on changing a 1-inch or 2-inch air filter every month. You’ll likely need to replace a 4-inch filter every two months and a 5-inch filter every three months.

If you have one pet, your home experiences only moderate dust accumulation, or no more than one smoker lives in the residence, filter replacement can shift to two, four and six months, respectively.

If the air in your home is mostly free of dust and completely free of pet dander and smoke, you can replace your filter just once per year.

Some filters are more efficient at filtering air than others. My advice is to buy washable furnace filters that offer the highest level of filtration. Make certain the filter fits exactly. Be sure to post a note on your calendar to remind yourself of how often to change furnace filters in your home. Check your filter every month for the first year after installation. If you find that your filter gets dirty faster than you anticipated, plan to replace it more often in the future.

Photo by Dreamstime/Luckydoor: Keep the air you breathe free of debris by regularly replacing filters.



Suitable supplemental lighting is better for starting seeds than the light coming through most windows would be. A setup of lights will allow you to grow a much wider range of vegetable varieties, which will make your garden even more interesting and fun. Until recently, most seed starters used inexpensive fluorescent T12 shop lights, with the height of the lights adjusted so the plants were very close to the bulbs — within a half-inch for full-sun plants, such as tomatoes and peppers.Indoor Grow Lights

But two new and better choices, T8 and T5 bulbs, are now available. In fluorescent-light lingo, the “T” stands for “tube,” and the number represents the bulb’s diameter. Old-line T12 fluorescent bulbs are still cheap and easy to find, but for a few dollars more per bulb, you could upgrade to more slender T8 bulbs, which are up to 40 percent more efficient. Plants get plenty of light when grown within 2 inches beneath T8 bulbs. You can usually find a 4-foot-long, Energy Star-certified, two-bulb T8 fixture at retail stores for about $20, plus another $10 for the bulbs.

Many garden-supply stores now offer grow lights that use even skinnier T5 bulbs, sometimes called “high output” (HO) fluorescents. Less glass is required in their manufacturing, and T5 bulbs are 9 percent more efficient than T8 bulbs and 51 percent more efficient than the old T12s. While T5s are some of the best grow lights for starting seeds indoors, as they set the standard for light output and energy efficiency, they may be glaringly bright if not equipped with a reflective hood. Plant height must be closely monitored, too, with no less than 3 inches of space between the bulbs and the tops of the plants. Some people find the narrow T5 bulbs too delicate to handle in 4-foot lengths, and instead choose shorter, 2-foot bulbs. 

For more information on growing your own vegetable seedlings, see Best Tips for Starting Seeds Indoors.

Photo by Jerry Pavia: Sprouting seeds will flourish beneath bright, efficient fluorescent bulbs.























Photo by Steve Maxwell







Photo by Steve Maxwell






When the cast iron is clean, re-season it by applying the cooking oil of your choice all over it. Preheat your oven to 350 degrees Fahrenheit, and bake the piece upside down for an hour. Don't line your oven floor with aluminum foil, as it can melt and fuse to the bottom of some types of ovens. Instead, if you need something to catch drips, use a cookie sheet placed below the cast iron. After an hour, turn off the oven and let the piece cool.







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