Ah, that's just what any fact-based, fair-minded discussion on chemicals and the environment needs – scare tactics, cloaked in deceit and unwarranted innuendo.

Glyphosate is the active ingredient in Roundup, a product used by many gardeners to kill weeds. The 60 Mintues news story broadcast over the winter pertained to our government's current efforts to hinder cocaine production by spraying Columbian coca fields with a highly concentrated solution of glyphosate. The story delivered pretty strong evidence that this practice was affecting the health of nearby villagers, and attributed to the spraying a wide range of skin problems and other health concerns. Noting the inaccuracy on the part of the pilots flying the helicopters, combined with wind drift, it was fairly obvious to me (even after processing the information through my CBS News filter) that these health problems are indeed a result of the villagers being sprayed.

Proving what Monsanto, the largest manufacturer of glyphosate-based herbicides, has always announced in a clear, loud voice: don't get the stuff on your skin, in your eyes, your hair, don't inhale it, smoke it, or mix it with vodka. If you follow the label directions when using Roundup – rubber gloves, long sleeves, safety goggles if you're a clutz – your health, and the health of the planet, is not at risk.

But wait a minute – rubber gloves, long sleeves, warnings on the label – doesn't that mean that the glyphosate in Roundup is a dangerous chemical? Of course it does, but in a fair discussion, one needs to consider the relativity of the word "dangerous."

Pour an ounce of Roundup in one fish pond, an ounce of Palmolive dish soap in another, then see which one kills the fish. Those evil scientists at Colgate-Palmolive will win every time. So is liquid soap a dangerous chemical? In a pond it is, and to fish, it's toxic. Or consider how one can't go more than a few weeks in the fall without coming across a story about a college student dying of alcohol poisoning. Are you supposed to not drink the stuff? No, but to be safe, you need to drink alcohol within certain guidelines.

Roundup kills weeds because glyphosate (a salt compound) inhibits enzyme pathways, preventing plants from synthesizing amino acids necessary for growth. It basically stops plants from eating, so they die. When used according to label directions there is no carryover into the soil or groundwater. You may seed an area sprayed with Roundup seven days later, and your dogs and children can walk in any area sprayed with Roundup after waiting just 24 hours. Yes, glyphosate typically has a half-life in the soil of around 30 days. (Half-life is how long it takes a compound to break down halfway.) Well, everything has a half-life in soil. A 30-day half-life is amazing, to be so brief. Registering a half-life is a bad thing if the compound, during the half-life, adversely affects the soil, or groundwater, or plants to come, and it doesn't mean anything if it doesn't. Glyphosate doesn't.

Agent Orange is a completely different, unbelievably more powerful toxin. It's pretty well understood now that just whiffing it can cause a wide range of diseases, and that living in areas that were sprayed can cause birth defects in humans. It remains in the soil indefinitely. Over in Vietnam right now, areas that were sprayed in the '60s are still not suitable for growing crops. Disturb that soil today and the chemical is released once again, causing major harm to humans, wildlife, flora, and the environment in general.

I work to protect the environment. My attitudes about chemicals have changed over the years. One of my goals as a gardener is to use as few chemical compounds as possible. Most seasons I don't use any. So please don't think I'm pro-chemical, because I'm not. But rest assured that I am, and forever will be, anti-deceit.

"Moss growing in your lawn is a sign of acidic soil"

Here we have one of the most dangerous kinds of myths possible: one that is only vaguely correct.

Yes, low pH, i.e. acidic soil, can contribute to moss growth in the lawn. But low pH alone is almost never the cause for moss growth. But that doesn't stop gardeners with a moss-in-their-beloved-grass problem from resolutely scattering lime dust all over the area spring, summer and fall-only to discover that moss will grow quite handsomely in "sweetened" (high pH) soil. Go take a hike along the Mississippi River some summer. What's that growing on the limestone bluffs? Moss.

To grow moss in your lawn, all that is required is insufficient sunlight, low soil fertility, compacted soil, dampness, low pH, usually in a combination of two or more of the above. Achieve all those conditions in a single patch of yard and I say to hell with growing grass, set up a Zen garden. You'll have moss covering a new statue of Buddha in about twenty minutes.

Lack of direct sunlight is the number one contributor to moss in the lawn. It's always shady where you find it. Again, I don't care if your soil pH is 5.0, if the area is getting a full day of sun, moss won't grow.

The area is usually wet. Well, that makes sense; shady areas stay moist longer. Low soil fertility is another condition that welcomes moss. Low soil fertility in lawns is the norm for 99% of the lawns in America; that's why the Scotts Company is on your radio right now advertising that now is the time to apply the first of your FOUR recommended lawn fertilizer applications for this season. Compacted soil is another great moss incubator. Compacted soil makes it tough for grass to take hold and flourish. The lawn stays thin, allowing ample room for moss.

Don't be out there spraying "Moss Buster" all over your poor, hard, dark, damp, infertile lawn. It doesn't work. Nor does raking it all out. It'll just grow back thicker. Moss is only the result of the problem-fix the problem.

• Here are some ways to get rid of moss in your lawn:
  If shady, open up the area to allow more sunlight (polite way of saying take some trees down).
• Rent a lawn aerator and run it over the mossy area three times, down, across and diagonally.
• Amend the soil with organic matter.
• Grow the proper grass type for the environmental condition, and fertilize the area spring and fall.
• Get a soil test, and if the soil has a pH level lower than 6.5, adjust it according to recommendations of the test.

Personally, I'd go with the Zen garden. Moss is a sign that nature is not in agreement with your desire for lawn. It's saying, "Think about it."

"Arborvitae grow in shade"

A vexing myth because, taken at word value, it's true. But this particular truth is not what you want to hear.

That arborvitae grow in shade is just the nursery industry stating, correctly, that arborvitae don't die in shade. But that's about it. When grown in anything less than five hours of direct sunlight, arborvitae (Thuja occidentalis) don't grow quickly, they don't stay tight, and they sure as heck don't make any type of formal, clipped hedge.

Too often, that's what homeowners expect. Want a nice, evergreen hedge in a shady spot? Landscape designers will tell you to grow arborvitae. Helpful staff at the nursery will say the same thing. They're not wrong, but you'll be disappointed. Any of most popular arborvitae varieties, 'Techny,' 'Rushmore,' 'Pyramidalis,' or 'Holmstrup' will start out tight and full (they've been field-grown in full sun), but over the next three to five years they'll get loose and lanky.

Is there any recourse? You could try growing yews (Taxus spp.), an evergreen that will perform much better in part sun to shade, but you have that vexing winter burn problem. The trick is to water yews well in their youth, then erect a burlap shade wall six inches away from the shrub blocking it completely from winter sun. After four or five years of developing a good, hardy root system, well-maintained and fertilized yews will not burn in the winter, and one can dispense with the burlap. As is the case with all evergreens, watering yews in the fall straight up until ground freeze is also an essential task.

"Adding peat moss to your soil will lower the pH"

True, but only to a very small degree.

A lot of times, gardeners cast peat moss onto their garden beds at various times of the year in the mistaken belief that they are lowering the pH. They add a layer around azaleas, or blueberries, for instance. A test of the soil in the root zone before and at any time after would show a negligible change in pH, or none at all.

Truth is, you can add two big bales of the stuff (eight cubic feet) and rototill it in to a bed as small as 100 square feet and with luck you'll drop the pH by half a percent. Not much good if you're dealing with sweet soil with a pH of, say, 7.5. You'll only knock it down to 7.0 (neutral).

The best way to lower soil pH is to use soil sulfur, in the amount prescribed by a proper soil test. If you want to grow blueberries, for instance, you can send in your soil and note that your intent is to grow blueberries. A good university test will tell you exactly how much soil sulfur to add.

Peat moss is fairly wimpy as a general soil additive, it should be noted. Yes, it lightens the soil, and retains moisture, and is a good choice for mixing with black dirt and a little sharp sand if you are making your own potting soil. But realize that peat moss compacts very quickly. Two, three years after adding it to soil, it's about gone. Compost and composted rice hulls are better overall soil additives.

"Gasoline in a can or tank is good all season"

Here's something very important I just learned two weeks ago: gas burned in small engines should be no more than thirty days old. Not being aware of the reasoning behind this decree just cost me $105 in small engine repair bills.

Do you do what I've always done, head out in the spring and fill a five-gallon plastic gas can with unleaded, then use it during the summer in your lawn mower, rototiller, and woodchipper? How about the one-gallon can that you fill with a 50:1 oil mix so you can fill up the chainsaw or mini-tiller all summer long?

Well, my little Mantis tiller has never run well since the first summer I gave in to the magazine ads and bought it. And my chainsaw has run rough the last few years. Even the new, 5 h.p. rototiller I bought last year was a royal pain to start every time this spring. And I was doing everything right when it came to storing these devices over winter, you know, running them dry, oiling the cylinders, basic manual stuff.

Still, since early May I've been victim to a small engine revolt; absolutely nothing was running right. Finally I took them all in to my local, very good small engine repair shop, and the head of repair told me that when it comes to small engines and today's gasolines, you have only thirty days to use the fuel before it begins to clog up a small engine carburetor.

He explained that today's unleaded gasoline is of such lesser quality than the product we bought only five years ago that it gums up a small engine's carburetor after it has been sitting in the machine's tank (or the five gallon can in your garage) more than thirty days.

So now I only buy the amount of gas I will use in a month. If I'm rototilling but don't think I'll use a whole tank during the job, I fill it up halfway. Same for the chipper – I might use it for an afternoon in June, then not fire it up again for four months. So I only fill the machine's tank with what I'll use that day. The lawnmower never has gas in the tank for more than a week or two, but how long has the gas been in the can from which you're filling it? That's why I'm now filling my plastic gas can at the pump only a gallon or two at a time.

I have $105 in carburetor repair bills to prove the theory. One last tip: if you do have gas in a storage can for more than a month, straight or mixed 50:1 with oil, pour it into your car or truck tank. Your vehicle will burn the "old" gas up without any problem.

"You need to add extra nitrogen to the soil anywhere you use shredded bark or wood chips as mulch."

Not true, but I do like the fact that this newer myth originated from people starting to hear and learn more about soil science.

Yes, wood that has not been composted will eat up a lot of nitrogen when dug or rototilled into the soil. Fresh sawdust in the soil or compost bin is a common culprit. Add sawdust to your soil (or uncomposted grass clippings, or shredded leaves) and foliage will turn yellow pretty quick. But shredded bark or wood chips in a four- to six-inch layer around your trees and shrubs is on top of the soil, not in it.

Your standard fertilizer program for trees and shrubs from spring through August 15th will add more than enough nitrogen to compensate for the negligible amount lost in the surface soil as wood mulch decomposes. If you never fertilize your trees and shrubs and use a wood mulch, then you really should break down and start using some fertilizer in the spring, and then at least one more time, say around the end of June.

But that's more for the overall benefit of the plants than to compensate for any problems caused by wood mulch eating up nitrogen. And remember, granular fertilizers beat the pants off water-soluble fertilizers every time.

"Groundcovers have a tough time under pine trees because the soil is too acidic."

No. Test the soil before making that assumption.

Only rarely will one find the pH of the soil under pine trees to be more acidic than surrounding soil. Pine needles don't add all that much acidity. If the soil around your yard tests at 6.5, the soil under the tree is probably 6.5. If you have alkaline soil, soil under a pine may drop to neutral, but it's not going to be deathly acidic.

Groundcovers struggle under pine trees because the trees suck up all the moisture. We plant a nice shade groundcover under and around the tree, don't water it heavily the first couple of seasons, then when it dies, we think the soil is too acidic.

The soil is fine. It's just dry. The pine has a zillion secondary and tertiary roots lying only a few inches below the surface, and they're using up all the moisture and nutrients.

Go ahead and plant your pachysandra, lamium, ajuga, asarum, and polemonium under pines (or spruce) but be sure to water them every week, more often in dry heat of summer. They'll do fine.

"Vegetables grown in beds edged with copper chromium arsenate-treated wood are unhealthy to consume."

No, turns out they're all fine. Despite all the hoopla, a study just concluded by the University of Minnesota shows conclusively that there is zero concern when it comes to eating vegetables grown in beds and boxes made from CCA-treated planks or timbers.

CCA came into use in the early '80s. Any treated wood in your house, on your deck, in play equipment, or girdling a garden is probably treated with CCA. It's now banned by the EPA (final phase-out by 2004) and that's a good thing, but there is no need to panic when it comes to garden use. Vegetables grown in treated boxes built twenty years ago (or three weeks from now) pose no health hazard relative to CCA contamination.

"When planting a tree, dig a hole twice the diameter of the container."

Since the 1800s, everything written about planting a tree tells you to do just that, of course, the old "forty-dollar hole for a twenty-dollar tree" myth. But university studies in the past few years tell us that your goal when planting a tree is to dig as wide a hole as possible, a five-hundred-dollar hole for a twenty-dollar tree.

Turns out that too often, roots from trees planted in a modest hole never break out beyond the hole to any healthy degree. Often, the roots circle around the hole, and hopefully don't girdle the tree. Except they do, to some degree, meaning the tree never takes off, never becomes vibrantly healthy, and is prone to dying young, if not blowing over in a storm.

So dig your hole as wide as possible. I dig a hole about two or three times the diameter of the container (or width of the root ball, when planting balled-and-burlapped (B&B) plant material). Then I rototill out and around from there, busting up the soil as deeply as possible. How far? In a new landscape, if I can get the trees and shrubs in before the sod goes down, I'll rototill as wide as twenty feet in diameter if the soil in the area is compacted.

In tight situations, or lousy soil, do what the Norwegians do: dig your hole as wide as possible, then dig four to six troughs out away from the hole, resembling the shape of a samurai star. Replace the loosened soil into the troughs, and years later, the tree's roots will have extended away from the tree down the troughs.

"Wrapping the trunk of a young tree with paper tree-wrap in the fall prevents winter sun scald"

No, wrapping the trunk of a tree with paper tree-wrap makes matters worse, and that's been proven in studies conducted by the University of Minnesota School of Horticulture.

That brown paper wrap we buy in rolls should no longer be used. Turns out that it gets moist in the winter, from rain, sleet, snow that melts in sunlight, and then it traps moisture between the wrap and the trunk. Even when the paper appears dry, the bark may not be. Now the sun sets, temperatures drop into a nice freeze, and the bark of a young tree cracks more readily than if we had done nothing and left the tree to fend for itself.

Instead, two options: buy those white, plastic, ribbed tubes with a slit up the side and slide those over the trunks of your young deciduous trees (but be careful not to slit the bark with the sharp edge) or, do as the Renegade Gardener does. I took some 1" x 6" boards left over from a fencing job and screwed a pointed stake into the bottom of them.

In October, I pound the boards into the ground vertically on the southeast and southwest sides of the trunk, about six inches out. I pound them in tight to one another, so the edges butt up. In other words, I shade the trunk from the sun with boards, via a two-board mini-fence on the south side. I cut the boards to the proper height, so that the trunks of young trees are shaded from the ground all the way up to the first main branches.

The trunks are shaded from direct sunlight all winter long. Best of all, these "mini-fences" are darn close to attractive.

"You can plant ball and burlap (B&B) material without removing the wire cage or burlap."

Stumbled upon this ghastly practice TWICE in the last few months, both times perpetrated by "professional" landscapers. If alleged pros are still this naïve, I'm betting many homeowners are making the same mistake.

Twenty years ago the theory was that you dumped B&B material right into the planting hole, without snipping off the steel basket or removing the burlap. The assumption was that the burlap would mulch away, and the steel basket couldn't do any harm. Turns out, only the basket part was true.

Studies by the University of Minnesota and others have found that even after six to eight years, the burlap is still not fully decomposed. More important, after three years in the ground the burlap is barely weakened. In tests, trees were planted without removing the cage or burlap. Three years later they were dug up. In nearly every case, primary and secondary roots had not penetrated the burlap (try to poke a stick through burlap – it's tough). The only roots managing to grow through were the fine, tertiary roots.

This makes for a very shaky, lethargic tree. Test trees planted this way but not dug up didn't begin to advance with anything approaching vigor until their fourth or fifth year in the ground. Lacking advancement by their primary roots, they stood still for three years. Some left to watering by nature, died. Test trees planted side-by-side, with cage and burlap removed, grew faster from the start, and after four years were noticeably larger in both height and trunk diameter.

The first photo shows an ornamental pear tree planted four years ago in a landscape I was renovating. When I saw it, right away I noted the telltale sign of abuse (you can see two of the hoops of the wire cage to the right of the trunk). The burlap had to be there as well, because you can't remove the burlap without first cutting off the cage. Sure enough, it was there, pretty well intact. The landscaper hadn't even bothered to remove the twine around the base of the trunk, also visible in the picture (and geez, that's the easy part!).

True to test results, the homeowner told me that the tree has sat like a statue for three seasons. At another client's house this spring, I arrived a week after a landscaper had planted three, twelve-foot river birch in a neighbor's yard. Due to rain a few days before, from thirty feet away I could see the steel cage, twine, and burlap poking up out of the ground at the base of each tree. The landscaper had scraped out three holes with an auger attachment on his Bobcat, stuck the trees in, kicked some dirt back, taken the homeowner's check, and split. This is a thousand dollars worth of trees we're talking about.

The second photo shows a river birch properly prepared, by me, for planting. First thing I did was dig a big enough hole that I could work comfortably around the root ball. After lowering the tree in, I leveled it by tossing a little soil under this part of the ball and that, until the tree was straight. Next, using a bolt cutter, I snipped the steel cage off as far down as I could reach.

Then I took my serrated knife and removed the twine tightly circling the trunk. Leave it on and it will strangle the tree, until it finally decomposes, or the tree grows over it. Next I cut the burlap in a complete circle around the root ball, at the point where it sat on the ground. Then one cut from the top of the burlap at the trunk down one side to this first cut, and all the burlap pulls off in one piece. Oddly similar to filleting a walleye. (And yes, thusly planted, the root ball is actually smooshing down on a little circle of cage and burlap, not a problem.)

It was late in the season, so this birch had some tertiary root growth sticking out from the burlap, from having been healed in all summer. So I gave it a nice clean root pruning to stimulate growth (bottom picture).

Lastly, I put the soil back in. I had amended the hole and soil with composted rice hulls, because the site where I planted the birch was home to the most evil, demonic, godless, pure potter's clay (mixed with large rocks) I have ever encountered in my life. Filled the hole half with soil, stepped it in to remove air pockets, watered it, added the rest of the soil, stepped it lightly, watered it again, done.