Q. Mike knows a lot, and I love the show (I listen on KSFC; 91.9 FM), but on a recent program he referred to hay and straw as if they were interchangeable. Straw is a stalk, usually a waste product of wheat, that's used as bedding for barnyard animals. Hay—typically alfalfa or a grass—is used as animal feed.

---Mary Beth in Spokane (Washington)

A. I can think of a lot of times when I spelled out the differences between hay and straw, but never when I confused them. And luckily, I think I'm innocent this time as well, although I could maybe have used slightly clearer language. Mary Beth is referring to a phone call that aired on the show several weeks ago about 'straw bale gardening'. I explained that one of my (many) objections to this method was the fact that the original material was almost certainly sprayed with lots of chemical pesticides and herbicides. But I added that if you knew an organic farmer who bailed hay, their straw would be clean of chemicals.

Wait a minute—did I just confuse the two terms again?

Nope. But it is a fine line. Straw and hay both begin life the same way—as a field crop. The word 'hay' refers to the entire harvested plant, including the seed heads. Most hay is grown to be used as animal feed, and is generally, as Mary Beth correctly notes, timothy, rye, alfalfa or a specialized grass. But cereal crops like wheat, oats and barley are sometimes grown for animal feed as well as human consumption.

When the plants are left intact and bundled up, it's hay. But when the seed heads are removed, the plant stalk that's left behind is straw, a hollow tube that has many uses, including animal bedding on farms and mulch in gardens . And if the hay was grown organically—say, to feed certified organic animals, any straw made from that hay would be free of chemicals.

In other words, you have to have organic hay (or grain) before you can get organic straw.

But the main point in any conversation about these topics is to warn people to be careful that they DON'T get hay when they buy 'straw bales'. Straw and hay are often packaged up identically, and many garden centers—and even farmers who sell their extra bales on the roadside—use the term 'straw' whether the bale in question is straw or hay. And if you use hay—with all those seed heads intact—as a garden mulch, the seeds will sprout and you'll become an unintentional grain farmer.

…Which happened to me once. I hadn't yet learned that you have to visually inspect the bales for seed heads, and picked up a batch of hay that was labeled as 'straw'. The plants that popped up a few weeks after I spread it as mulch taught me two important lessons….

One was to never trust signage. The other was that wheat is sharp. Not a good plant to grab in anger bare-handed. But enough old war stories; let's move on to 'straw bale gardening' itself.

Q. It's always a struggle to try and work our clay soil. I read an article about how this problem could be solved by using straw bales instead of my having to schlep bags of manure, peat moss, etc. to grow my tomatoes, peppers, and cucumbers; but my husband disagrees. What's your opinion?

---Eileen in Langhorne, PA

A. I think it's just another of the 'trends' that garden writers pick up on when they're desperate for something 'new' to write about, and that they don't subject to any critical thought. But I was raised by a homicide detective, and I'm always looking for the hole in the logic. And in this case, I came up with five right off the bat.

The bales were almost certainly grown with pesticides—including hideous 'systemic' chemicals that are taken up by the plant itself. I only grow organically, and so I'm out before we even start. The bales don't retain moisture well; in a dry year you'd have to be watering them every day—perhaps several times a day. But because straw is packed so tightly, the cores and bottoms do collect a lot of moisture that they can't get rid of and tend to mold up—especially in a wet year. You have to buy new bales every year, which is far from sustainable. The system is lifeless; designed to avoid soil and compost in favor of chemically-laden straw and nasty chemical fertilizers .

And that last one is perhaps my biggest issue emotionally. My approach to gardening—forged in the fires of greats like J. I. and Bob Rodale, Sir Albert Howard, Eliot Coleman, John Jeavons, Mel Bartholomew and so many others—is that HEALTHY SOIL is the basis for all gardening. The answer to clay soil is not to grow in pesticide laden straw bales (which are really heavy, by the way—so the schlepping factor is not decreased one bit).

Raised beds and real containers are a much less toxic and much more sustainable response to clay soil; fill them with a nice mix of potting soil, screened black topsoil, perlite and compost. (NOT manure or peat moss; those are far from the best soil amendments.) Then you're away from the clay, growing in a medium that isn't pre-contaminated with chemicals, drains well in wet years, goes longer between waterings in dry years, and doesn't need to be replaced every year.

And one that you can naturally nourish with compost, worm castings and other organic matter instead of salty chemical fertilizers.