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Answers to your questions about gardening, energy, homesteading and other sustainable living topics.

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What’s the difference between a “passive solar” home and a home built to “Passive House” standards? Is one better than the other?

“Passive solar” is a design approach that was popularized inPassive House Standards the 1970s and in which heat from the sun is strategically captured to warm homes. Passive solar’s low-tech approach doesn’t abide by any established standard, but the design principles are consistent: Passive solar homes capitalize on solar heat that radiates through south-facing windows (north-facing windows if the home is in the Southern Hemisphere). As the sun warms the house, the heat is retained via insulation and by use of thermal mass — such as concrete, stones or tile — that stores and slowly releases it.

About 20 years after the popularization of passive solar homes, German physicist Wolfgang Feist founded the Passivhaus Institut (PHI), which formalized “Passivhaus,” a comprehensive energy-efficient building standard that was influenced by early passive solar designs, but which placed more importance on an airtight envelope, high-efficiency windows and conditioned air recovery. By 2010, the newly formed Passive House Institute U.S. (PHIUS) had carved out a place for the extremely efficient, very specific and highly demanding standard in the U.S. market. PHI and PHIUS are now working separately to advance Passive House standards in the United States.

The goal of the standard is to achieve a durable, comfortable home with overall energy savings of 60 to 70 percent compared with conventional new homes, including a 90 percent reduction in space-heating requirements. A home must follow the standard exactly to receive Passive House certification. With the dramatically reduced energy requirements, the need for conventional heating and cooling systems disappears. This frees up financial resources that can instead be used to make a home deeply efficient. Adding renewable energy systems becomes more affordable, because a smaller energy-generation system can now meet the much smaller energy demands of a certified Passive House.

The rigorous Passive House standard doesn’t render passive solar design entirely obsolete, however. Many homes built to the Passive House standard rely on passive solar design as one tactic among many to make the home super-efficient. But Passive House certification goes beyond passive solar details and ultimately offers superior performance. Thanks to modern building techniques and products, Passive House buildings allow for far more design innovation than passive solar homes, particularly for structures without ideal sun exposure. Regardless, buildings should incorporate passive solar techniques before active solar techniques, such as solar panels, enter the picture.

For more information, visit the websites for the Passivhaus Institut and the Passive House Institute US.

Photo by Rick Pharaoh Photography: Passive House-certified homes combine captured sunshine and high-tech design for increased comfort and deep efficiency.


I have heavy clay soil that becomes as hard as a brick when it dries, and my neighbors who also garden have asked me how to improve clay soil. What are the best methods for improving clay soil?

First, the good news: “Of the three major soil components — sand, silt and clay — clay has the highest nutrient content,” says Garn Wallace, president of Wallace Labs, a Improve Clay Soilsoil-testing firm in El Segundo, Calif. Clay soils retain minerals in forms that are readily available to plants and that aren’t water soluble, so rain and irrigation water are less likely to leach them away. The trouble is that clay lacks good porosity. Its fine-textured particles tend to clump tightly together. Air, water, roots and seedlings can have trouble moving through it, so crop yields may be lower. (Plus, clay is a pain to work in!)

Increasing your soil’s organic matter is the first and most important step toward improving heavy clay soil. Organic matter invites in more porosity-improving earthworms. Work in compost, grass clippings, shredded leaves or other organic materials. Plant and turn under cover crops, and safeguard your soil’s surface with an organic mulch to prevent crusting. Sand or peat moss can also improve soil texture, but they lack many of the other benefits of organic matter, such as beneficial microbial activity and nutrients for your plants to uptake. Plus, you’ll need a lot of sand to make a real difference (1 part sand to every 2 parts clay soil).

Photo by Dreamstime/Ian Nixon: Don’t be foiled by your heavy clay soil: Add organic matter to soften up your tough terrain.

Vicki Mattern is a contributing editor for MOTHER EARTH NEWS magazine, book editor and freelance magazine writer. She has edited or co-authored seven books on gardening, and lives and works from her home in northwestern Montana. You can find Vicki on .


I’ve heard there’s a link between catching colds and flying. Am I more likely to get sick if I travel on a plane?

Yes! According to a 2004 study Catching Colds and Flying on Planespublished in the Journal of Environmental Health Research, plane travelers are up to 113 times more likely to catch a virus than their ground-bound counterparts.

Why is this? The study put forth a series of potential culprits: fatigue, low outside air replacement, dry cabin air, and proximity of people to one another in a small space. While all of these may play a part, the researchers found that an airplane cabin’s low humidity — which weakens humans’ defenses against infection — is likely the greatest factor in passengers’ heightened susceptibility to infection.

Use these preventive tactics to keep from catching a cold the next time you catch a flight: Get plenty of sleep before your trip, stay well-hydrated, wash your hands often, and avoid touching your face or mouth. Boost your immunity pre-flight by supplementing your diet with medicinal herbs, such as astragalus, garlic, ginger and ginseng, and medicinal mushrooms, such as maitake, reishi and shiitake.

For even more helpful information on staving off infection, check out our comprehensive article 19 Ways to Prevent and Treat Colds and Flu.

Photo by Fotolia/Subbotina Anna: Preventive tactics such as getting plenty of sleep and staying hydrated can help prevent sickness when flying.


Can you recommend some tomato varieties that will continue to produce fruit when temperatures are high?

Faced with long bouts of daytime temperatures higheHeat-Tolerant Tomato Varietiesr than 85 degrees Fahrenheit and nights above 72 degrees, tomatoes may fail to set fruit. The plants may look dark green and vigorous — evidence that all other growing conditions are favorable — but have blossoms that dry up and fall off.

If the heat spell lasts no more than a week, the tomato plants will quickly recover. During long stretches of warm nighttime temperatures, however, the plants will stop setting, causing a subsequent gap in tomato production.

In recent years, a flood of new varieties has been bred for greater heat tolerance. Known as “heat-set” tomatoes, or “hot-set” tomatoes, some commonly grown hybrids are ‘BHN 216,’ ‘Florasette,’ ‘Florida 91,’ ‘Heatwave II,’ ‘Solar Fire,’ ‘Summer Set,’ ‘Sunchaser,’ ‘Sun Leaper,’ ‘Sunmaster,’ ‘Sun Pride’ and ‘Talladega.’ According to the Alabama Cooperative Extension System, many heat-set varieties also perform well in cool, rainy weather.

Some heirloom tomato varieties are heat-tolerant as well, and these include ‘Arkansas Traveler,’ ‘Eva Purple Ball,’ ‘Hazelfield Farm,’ ‘Homestead 24,’ ‘Illinois Beauty,’ ‘Neptune,’ ‘Ozark Pink’ and ‘Tropic.’ Additionally, some “cold-set” varieties, such as ‘Stupice,’ are all-weather standouts because they’re able to function in hot weather, too. A handful of cherry tomato varieties, such as ‘Lollipop’ and ‘Yellow Pear,’ also do well in prolonged stints of heat.

Tomato growers in the South often choose heat-tolerant tomato varieties for summer and fall production — a strategy growers farther north may want to emulate now that climate change is causing hotter summers in most regions. When growing tomatoes in hot temperatures, you can boost your success rate by planting deeper (where the soil temperatures are lower), providing afternoon shade, watering in the morning and using thick organic mulch to keep soil cool.

Learn more about heat-tolerant tomato varieties in the Alabama extension publication Blossom Drop in Tomatoes and the Louisiana extension publication Performance of Hot-Set Tomato Varieties in Louisiana. To find sources for some of the heat-set tomato varieties mentioned here, use our Seed and Plant Finder.

Photo by Tomato Growers Supply Company: 'Stupice' tomatoes thrive in cold weather and can also handle heat.


Do wild animals that are trapped and released in new locations manage to survive?

Though critters roaming your yard can be a nuisance, controlling wild animals by live-trapping and releasing them is not recommended by most wildlife biologists. An animal’s odds for survival Relocating Wild Animalsin a new location aren’t very good, according to the Washington Department of Fish and Wildlife (WDFW).

“While releasing wildlife in a new location is an option often preferred by well-meaning people opposed to killing animals, this may be at the expense of the released animal or the animals at the release site,” says wildlife biologist Russell Link in the WDFW publication Trapping Wildlife.

Many animals cannot survive the stress and trauma of being trapped and then moved to an unfamiliar location. A relocated wild animal might become involved in a territorial dispute, especially if its species’ local population is already at or beyond its limit. If the animal does survive, it may try to return to its original home and be killed en route.

If you’re considering trying this approach to wild animal control, be particularly careful to avoid two circumstances. First, never relocate an animal when weather is severe. The animal could expend so much energy simply finding shelter that it dies soon afterward. Second, never move an animal that’s caring for young — relocating a nursing mother will almost certainly cause her offspring to die. (How do you know a nursing mother? The trapped animal will have enlarged teats with relatively little hair on them.) Wait until the young have left their nest, generally 8 to 10 weeks after birth, and plan to set multiple traps.

Many states (and some municipalities) have strict regulations about trapping, transporting and releasing certain animal species, which sometimes even apply to mice, rabbits and squirrels. Check with your nearest wildlife office to find out whether you need a permit or must follow certain trap-and-release procedures for relocating wild animals.

Photo by Dreamstime/Charles Brutlag: With wild animal control, what seems like a humane option may actually be a harmful one.

Vicki Mattern is a contributing editor for MOTHER EARTH NEWS magazine, book editor and freelance magazine writer. She has edited or co-authored seven books on gardening, and lives and works from her home in northwestern Montana. You can find Vicki on .


What does Certified Organic mean on food labels?

The “Certified Organic” label is, at its core, a consumer protection law. It’s the U.S. Department of Agriculture’s (USDA) assurance that you’re buying food that has been produced and processed according to its National Organic Program (NOP) standards: Certified Organic LabelVegetables and fruits have not been produced using irradiation, sewage sludge, synthetic fertilizers, prohibited pesticides or genetically modified organisms (GMOs); livestock have been fed 100 percent organic feed without antibiotics or growth hormones, and were raised with at least some access to the outdoors; and multi-ingredient processed foods must contain at least 95 percent Certified Organic ingredients.

The Certified Organic label is backed by regulations developed by the USDA and the National Organic Standards Board, an advisory committee of consumers, environmentalists, farmers and scientists. Part of the board’s job is to advise the USDA regarding the “National List of Allowed and Prohibited Substances.” But it aims to be more than an organic referee that rules a farming substance or practice either “fair” or “foul play.” The board also makes recommendations about sustainable agricultural practices, and if its recommendations are approved by the USDA, the law requires farmers who seek organic certification to demonstrate that they follow such methods.

To obtain organic certification, applicants must have their operations reviewed by a third-party certifying agent. The review process includes annual inspections, and inspectors can request samples of soil, water, and plant and animal tissue to test for chemical residues. Producers must also pay certification fees that range from a few hundred to several thousand dollars. For some growers, the financial cost and the rigorous path to gain a Certified Organic label are daunting. The law thus makes allowances for small operations. Producers who market less than $5,000 of organic products annually may call their products organic (but not Certified Organic) without going through the certification process, provided they comply with other regulations. (For more information on certification requirements, go to the USDA’s National Organic Program FAQ). Labeling a product Certified Organic without receiving USDA authorization is illegal and can result in prosecution and a fine.

Although some of the USDA’s decisions have been criticized by organic watchdog groups (such as The Cornucopia Institute), we’ve come a long way in organic food labeling. Before the national organic standards went into effect in April 2001, consumers had no way of knowing whether food labeled as organic was in fact produced using sustainable, environmentally sound practices. Today, we can know that farmers have produced food without using toxic pesticides, harsh fertilizers, and unsustainable — and sometimes inhumane — systems. Year-over-year increases in sales show that more and more consumers prefer to eat Certified Organic products.

Photo by SuperStock/Universal Images Group: Organic standards guide consumers who want to choose sustainably produced food.

Vicki Mattern is a contributing editor for MOTHER EARTH NEWS magazine, book editor and freelance magazine writer. She has edited or co-authored seven books on gardening, and lives and works from her home in northwestern Montana. You can find Vicki on .


Can you tell me the best way to store late-harvested crops?

Most crops can be canned, frozen, dried or pickled, but the best way to store many root crops and winter squash is to make use of cold storage areas in your home, such as in an unheated closet or bedroom, or in your basement or garage. You can even keep potatoes and carrots in an outdoor pit. If you don’t have a big garden, stock up on root crops at your local farmers market, and keep them edible well into winter with the tips in the following articles, which detail a number of simple cold-storage techniques.

Food Storage: 20 Crops That Keep and How to Store Them is complete with detailed charts that outline instructions for storing easy-to-keep crops, including apples, beans, cabbage, garlic, onions, potatoes and squash. Most storage crops should be cured before storage to heal small wounds and allow for the release of excess moisture that could otherwise cause them to rot. For five low-tech ways to store root crops outdoors, see Outdoor Root Cellars.

For a guide to grow, stow and cook crops that are productive, nutrient-dense, and easy to store or preserve, go to our Food Self-Sufficiency page.

To find more articles and tips on preserving food, peruse our Collection of Food Preservation Techniques.

Photo By Simon McBride: Cure fall crops and keep them cool to eat well, even out of season.

Vicki Mattern is a contributing editor for MOTHER EARTH NEWS magazine, book editor and freelance magazine writer. She has edited or co-authored seven books on gardening, and lives and works from her home in northwestern Montana. You can find Vicki on Google+.

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