2015 resolution: become a more thoughtful organic gardener, with jeff gillman

gillman booksPROPOSED 2015 RESOLUTION: Become a more thoughtful organic gardener. Simply avoiding synthetic garden chemicals by swapping them out for a product labeled “organic” isn’t enough—and in some cases, the substitute isn’t even safer, says Jeff Gillman, author of “The Truth about Organic Gardening” and “Decoding Gardening Advice” and more. Consider taking your organic thinking to the next step in 2015 (and maybe win his books to help in the process).

A candid head’s up: Like Jeff, I am less-than-enthusiastic about the seemingly widespread desire among gardeners to shop their way out of issues with pests, disease, or soil imbalances. I buy a lot of seeds and bulbs and plants–but not a lot of “stuff.”

Jeff and I had a funny email exchange, when I invited him to join me on the radio show and podcast, and asked about what topics he’d most like to cover together.

“The topics that I speak on most frequently are garden remedies and thoughtful organic gardening,” Jeff replied. When I read that, my slightly dark humor zoomed in on the phrase “thoughtful organic gardening.”

Except I thought he said, “thoughtless organic gardening.” I guess I was thinking of all the garden-center shelves of products labeled “natural” and “organic” that promise to fix everything–but at a cost that may exceed the sticker price.

Besides his multiple books, Jeff Gillman is a former Associate Professor of Horticultural Science at the University of Minnesota and was a Cooperative Extension specialist for 15 years. He now teaches at Central Piedmont Community College in Charlotte, North Carolina. You may know him as one of the team on the popular Facebook page The Garden Professors, and a blog by the same name.

Listen in now to our recent public-radio conversation about organic gardening, or read along, or both. The instructions on entering the giveaway are at the bottom of the page. Learn why vinegar is not recommended for weed control; why “bloom booster” fertilizers don’t boost blooms; what organic fertilizer leaves behind a radioactive waste product when it is mined, and more.

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my organic-gardening q&a with jeff gillman

Q. You write and lecture about making more thoughtful choices, Jeff—beyond just obeying some official list of what’s labeled as OK for organic gardening. You say you “don’t follow the party line about organics,” meaning that just because something is labeled “organic” doesn’t mean it’s the best choice. What is one example we’ll be surprised about?

A. People think if you have something that’s organic, it’s good. That’s not necessarily true. A good example: apples. You know the “dirty dozen” list that’s put out?

Q. Yes, of conventionally grown produce you should avoid because of the high level of pesticide residue.

 A. Apples are always one of the top two or three highest things on that list. The consumer is encouraged to purchase organic, to avoid pesticides.

But if a producer starts growing apples in, say, New York organically, and put up a sign that says “organic,” we assume they’re producing apples without pesticides. That’s the furthest thing from the truth.

The big problems don’t go away just because you’re farming something organically, and apples have four big problems: coddling moth, apple maggot, fire blight and apple scab. You’ve got to control them somehow, and if you’re not controlling them with synthetic pesticides, chances are you’re using organic pesticides.

Q. It’s important to understand: There is a list of pesticides (and other materials) that are approved for use in organic agriculture. They’re not synthetic pesticides, but are pesticides nonetheless. They have to be used with care.

A. A lot of our organic pesticides can be more dangerous than synthetic ones, and it bothers me that people don’t understand that. You look natural things, and you say, “How could these be as dangerous as synthetic,” and I say: Let’s look at a rattlesnake bite.

Q. Do we have to? [Laughter.] I live in a habitat for Eastern timber rattler, so that is a subject close to my heart.

A. A rattlesnake bite—the venom—is very natural, and also very dangerous. Organic pesticide producers can use things like pyrethrum, or copper compounds—and yes, these are natural. But that doesn’t make them any less dangerous than a synthetic compound.

Q. Apples that are grown East of the Rockies, where those four issues you described are real obstacles, for instance—growers need help in the fight.

A. Out West you may get away with fewer pesticides, but in many other areas, you are using pesticides, whether you are growing conventionally or organically.

Q. So sprays are being used, unless the crop is labeled “no-spray” apples.

A. And those tend to be very pitted and pocked, with all kinds of insects damaged. I grew up eating apples like that.

apples waiting for cookingQ. [Laughter.] And I am an expert in growing apples like that [above]—no-spray, but pocked and pitted—from my 100-plus-year-old trees, and make lots of applesauce and baked apples and so on. I love them, but they won’t win any prizes at the county fair.

A. Exactly—so what we need to change is people’s perception.

Q. I said in the introduction that I get agitated in the garden center sometimes seeing all the products that have been created to meet people’s desire for organic quick fixes. Shall we talk about fertilizers, maybe—there are organic ones. What about those?

A. There are many organic or natural fertilizers out there, and the wonderful natural fertilizers are the ones that are renewable. They come from plant type products.

Unfortunately, there are also a lot out there that come from non-renewable sources. The big one is actually rock phosphate. Rock phosphate is the source of Phosphorus in most of your organic fertilizers, and rock phosphate is actually a really bad product.

First: There are only so many Phosphorus mines in the world. We are running out of Phosphorus, because we’re mining it up. Just because it comes from a natural source doesn’t mean that we can’t use it up. Most of it ends up in the Mississippi and rolling out into the Gulf.

Rock phosphate is a non-renewable resource. When they mine this stuff, they produce a byproduct called phosphogypsum, which is considered a radioactive waste. So you’re using this natural product labeled for organic use, and it’s like oil—non-renewable. Plus you’re producing this kind of waste.

Q. And yet it’s on the list as approved for organic gardens?

A. There are plenty of things on the OMRI list [from the Organic Materials Review Institute], including rock phosphate, that are like that.

Q. Decades ago, with the organic gardeners who mentored me and taught me their tricks—rock phosphate was one of their favorite tools.

A. Yes, and there’s another issue: Phosphorus is often overused. It’s needed to a point, but just a very small point. We tend to add way too much, whether we garden conventionally or organically.

Q. Phosphorus is the middle number on any fertilizer bag, in the N-P-K ratio.

A. Yes, in the fertilizer analysis on the bag. You want the middle number to be lower than the first number. It’s all based on a ratio of the first number to the second number, and the ratio I like is about 5 to 1. Something that has a ratio like that: cottonseed meal, which I like as a natural organic fertilizer.

Q. And that’s renewable. So you try to look at things left over from other industries?

A. Bone meal, blood meal cottonseed meal, alfalfa meal—I like these as fertilizers.

Q. What can I make of “bloom booster” claims on fertilizer labels? Is that one of these Phosphorus claims gone mad?

A. It is. I just did a study for “Fine Gardening” magazine, and we looked at one of the bloom boosters compared to regular fertilizers to see how much it helps bloom. It didn’t help bloom any more than a control.

I have a hydroponics class, and we actually test plants growing with and without certain elements. Even removing all the Phosphorus from the solution, we grew some plants—and still had just as many blooms. Again: You need a little, but the amount people add today is absolutely crazy.

Q. And the idea that we do it knee-jerk, without testing. We just add stuff.

A. I would encourage everyone to do a soil test, if you want to fertilize wisely.

Q. Our mutual friend Joe Lamp’l was on the show not long ago, talking about just that. You can’t “amend” if you don’t know your starting point.

A. At least get yourself a baseline first.

Q. Depending on what pest or disease is emerging at a given moment, everyone always asks me what they can buy to kill ____ or cure ____. I always have the same answer: I never really buy much of anything except for potting soil. (They hate when I say that.)  And then they want to know my home-brewed formulas for success. And I say no, I don’t really have any.

A. There are a lot of crazy home remedies out there, and one that I dislike most is the idea of using vinegar for controlling weeds.  It kind of works—and looks like it’s working, but as it’s appearing to work it’s actually potentially causing environmental damage and probably not killing your weeds.

Everyone is against Roundup, and I am not a tremendous fan of it. But if you think vinegar is a safe alternative you are fooling yourself. When you apply vinegar you will kill the tops of the plants, but if you have a plant of any size at all, the root will remain intact.

And I want to tell you one of the worst things that actually happened to me: I was under my back porch, where there is some gravel mulch, and I had some strong vinegar spray I was testing. A 20 percent acetic acid solution, made for killing weeds.

Out of the corner of my eye I see a tiny frog, and I have accidentally gotten vinegar on it. I call for my wife to bring water, and I wash him off, but in less than a minute he’s dead.

I don’t want to give people the impression you should go out and use Roundup. What you should do:

Get yourself some exercise by kneeling down and actually—wait for it!—pulling weeds.

garlic mustard uprootedQ. And this is where everyone gets angry at me, Jeff, because they think I have a secret for weeds. My secret is I have the beat-up knees and hands to show for it. I dig them and pull them, and make a pass through each bed every week all season long. [Uprooted garlic mustard, above.]

A. I do have one pest remedy from a grower in Minnesota that I know of—re-closable mesh bags that you put around your apples or peaches or tomatoes to protect against insects. It’s a lot of work, but it really works. If you want to do it yourself and use a clear plastic bag, that’s possible.

Q. Like a mechanical barrier against insects—no toxins, just mechanical control, like with hand-weeding.

I’m almost afraid to ask you about other products in the garden center. [Laughter.] But right now, it’s anti-desiccant or anti-transpirant spray season, meant to prevent drying out of conifers and broad-leaf evergreens. Can we talk about those briefly?

A. I had thought they were a good idea when I first saw them, but then I read research on them and did some of my own. The problem is they’re supposed to clog the pores at the bottom of the leaf, so that water doesn’t come out. We used a perometer to test it, and it does block the pores—but for a few days at best.

It just doesn’t work very long. The leaf is constantly moving and the covering cracks.

Q. These are waxy, plastic-y materials?

A. Yes. They have been used since the 1920s, and it worked then because they were using a thick paraffin wax.  The stuff today doesn’t cut it.

We tested against Secret roll-on—an anti-perspirant is supposed to clog pores, too. And Secret kicked the butt of the anti-transpirant sprays, though I wouldn’t recommend it because it caused damage from some other ingredients in it.

mulch faqQ. So I have to ask:  If some of this “stuff” from the store often isn’t called for, and even home-brewed concoctions often don’t do the trick, either, what are Jeff Gillman’s top tools for garden success?

A. Number 1: The heart of the true organic garden is organic material, and building your soil. Two ways to build your soil: compost, whether from a store or your own yard. And a good organic—meaning natural—mulch. Pine chips, or bark, or hardwood chips

And then I will mention those renewable natural fertilizer sources again, like cottonseed meal and blood meal and bone meal. Used as directed in a conscientious way, of course.

Q. Care for your soil, and your plants will be cared for.

A. That all comes from Sir Albert Howard, the father of organic farming and gardening, which is based on building your soil.

enter to win the books

I’LL SEND A COPY OF one of Jeff Gillman’s books to each of two lucky winners. Enter by answering this question in the comment box at the very bottom of the page, below the last comment:

What can you do in 2015 to be a more thoughtful organic gardener, or are you already there?

I’ll draw two random winners after entries close at midnight on Sunday, December 28. US and Canada only. Good luck to all.

more from jeff gillman

(Disclosure: Affiliate links leading to Amazon purchases yield a small commission.)

prefer the podcast?

JEFF GILLMAN was the guest on the latest radio podcast. You can listen anywhere, anytime: Locally, in my Hudson Valley (NY)-Berkshires (MA)-Litchfield Hills (CT) region, “A Way to Garden” airs on Robin Hood Radio on Monday at 8:30 AM Eastern, with a rerun at 8:30 Saturdays. Get it free on iTunes, the Stitcher app, or streaming from RobinHoodRadio.com or via its RSS feed. The December 22, 2014 show can be streamed here now. Robin Hood is the smallest NPR station in the nation; our garden show marked the start of its fifth year in March, and is syndicated via PRX.


  1. Emily Shirley says:

    It sounds like a “To Do” list and it is, but it incorporates much of what I need to do to be a more thoughtful gardener. I am going to move a back fence and move my composting to new area so I can get to it more with the tractor and therefore “work it” like I should. I am going to research and understand exactly what is in this new “mushroom compost” that garden centers are pushing. I believe there may be more pesticides in there than we think, based on how they process it and what they use. I am adding “expanded shale” to all my raised beds. It is amazing how the soil holds the moisture more with expanded shale mixed in.

  2. lynn novick says:

    I am going to test my soil and get some better mulch–I use newspaper and chopped leaves but found out (in this Newsletter) a nursery near me carries SweetPeet.

  3. Sherry says:

    Can someone please tell me how to control digger bees? Every year late March early spring they come up out of the lawn and there are hundreds of them, we have tried Severn dust and in the liquid Severn and it’s seems Like they get wrose every year and no one can tell me what to do, I do t want to harm the good bees help.

    1. margaret says:

      Hi, Sherry. I don’t know where you live and what species of bees you are referring to as “digger bees” … which can in fact be “good bees” themselves, as this article from Clemson University explains. Apparently there is also a native “digger bee” in the desert regions, like AZ. Here in NY, I have some species of native ground-nesting bees as well — but none of these are pests or “bad.” So I’m not sure what to say without knowing if perhaps your problem is with some other insect?

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