Author: jeffgillman003

Soap and Deer

Short post today — Linda appears to have transmitted her illness electronically over a couple of thousand miles — Thanks Linda!

I was reminded yesterday that it’s almost time for gardeners to start worrying about winter deer damage. With that in mind I thought I’d share with you my favorite research article on the subject.  It’s a little paper by Michael Fargione and Michael Richmond and published about 18 years ago.  You can find it here.

This paper attempts to establish how repellent bars of soap are to deer and comes up with some very interesting conclusions.  The first thing you should know is that no one type of soap appears to be better than another.  The second thing you should know is that soap does appear to stop deer from feeding around the soap — but the best you can hope for is a radius of protection of about a meter from the bar of soap itself — Can you imagine what that would look like if you were trying to protect the lower limbs of a large tree?  And finally, bar soap appears to attract voles.  Based on my reading, and my limited experience, I’ve found that almost everything that people say repels deer does repel deer — human hair, peeing around a tree, predator urine, dried blood — the issue is how long these repellents stay effective and how effective they are when the deer get really hungry.  The most effective commercial deer repellents tend to have “putrescent egg solids” in then (rotten eggs) — I once had a graduate student who needed to protect some hazelnuts from deer and she found that a mixture of a few eggs (2-4) mixed in a quart of water and sprayed onto the trees worked pretty well — and no, the eggs weren’t rotten.  This mixture should be sprayed about once every two weeks if possible.

If Harvard Says That It Works Then It Works Dammit!

So back in September my department head (who is, for all intents and purposes, my boss) handed me a New York Times article (http://www.nytimes.com/2009/09/24/garden/24garden.html) about the grass at Harvard which is now being managed organically.  We share the opinion that many organic techniques, such as compost tea, are “Voodoo Science” (that’s a term I stole from Mike Dirr) and so she thought I’d be interested in the techniques that Harvard was using.  She didn’t say it explicitly, but I think she thought I’d get a laugh out of it.  And I did….Along with a funny feeling in my stomach.

After looking at the article I just couldn’t resist going to Harvard’s website (http://www.uos.harvard.edu/fmo/landscape/organiclandscaping/) and finding out all of the stuff that they’re doing to make their grass look wonderful.  And, to be honest, much of it is great.  They’re aerating more, they’re adding compost to the soil, they’re using fewer pesticides.  All of which I wholeheartedly agree with.

And then they’ve got this whole compost tea thing going on. In fact, they actually include information on how to make a compost tea brewer and different recipes for these compost teas.

For the uninitiated, compost tea is a mix of water along with other things — such as a carbohydrate source (like molasses, or flour, or sugar, etc) and maybe even a little bit of organic fertilizer — into which a “teabag” (usually something like a burlap sack) is dipped which contains compost.  Air is usually bubbled through the mixture, in part to reduce the likelihood of bad bacteria, like E. coli, infesting the mix (research has shown that this doesn’t work).  Supposedly the good microbes from the compost start growing in the spiked water producing a “tea” which is packed with microbial goodness for your plants.  The microbes are supposed to revitalize the soil as well as, potentially, helping it to ward off plant diseases.

Bullpucky.

This isn’t to say that I don’t think soil microbes are important because I do — they’re vitally important!  But why is it that some people think compost tea is needed to add them?  As a researcher and professor I’m supposed to try to stick to saying what the research supports.  Following those rules I’d like to add to a comment that Linda made the other day.  The research currently shows that compost tea is unlikely to do a darn thing for you — at least in terms of the microbes which it adds.  Compost teas, like the ones from the recipes at Harvard, will often have nutrients in them from the added compost (nutrients will leach into the water from the compost), or from fertilizers.  These nutrients can obviously provide some fertility to the soil (or to the foliage).  Beyond that fertility I am completely unconvinced of the value of compost tea.

So why are the people at Harvard raving?  Well, it looks to me like they did a bunch of good things, incorporated one Voodoo science technique, and then attributed an inappropriate amount of their success to the Voodoo science technique.  Go Harvard!

I’m going to close with an image of some roses (these are a small sample from a larger experiment) that I treated with compost tea to protect them from disease.  Don’t they look nice?  I have a number of researcher friends who have also tried these teas.  None has had a positive experience.

What Makes Growers Change?

Over the last few weeks I’ve said a lot of complimentary things about the Minnesota Nursery Industry and how they’re careful to avoid situations where trees are planted too deeply.  What I haven’t mentioned is that there is a reason for this.  During the 1980s and early ’90s trees were usually planted deeply with lots of soil over the uppermost roots.  It was just common practice.  Unfortunately this practice led to roots growing across the trees stems and, when those roots cross the stem, the roots always win  (as you saw in Linda’s quiz last week)!  Many, many trees planted in that era have trunks which enter the ground looking like the picture below.  You can clearly see the roots strangling the tree.  This photo was actually taken last year on this campus!

This tree is one of the lucky ones.  These girdling roots were removed, the layer of soil over the crown was removed, the crown of the tree was inspected, and it was determined that this tree could survive.  Many others planted during the 80s and 90s are not so lucky — in fact, many are suffering or dead.

An outcry over the last dozen years or so, mostly from cities (St. Paul and Minneapolis), led to changes in harvest by the nursery industry, and by the landscapers who install the trees.  Yesterday I received a plan for planting trees up and down a major highway here in St. Paul to review.  The specs were very specific — and similar to the specs that we see now across the Twin Cities and most of Minnesota.  Root flare must be at, or even above, the surface of the soil.

I don’t want anyone to get the wrong idea.  There are still those who sell nursery stock with the root flare buried deep under soil in the ball, and there are landscapers who dig a hole twice as deep as the depth of the ball before planting, but it’s becoming less and less of an issue as, in general, we seemed to have learned from past mistakes.

My Least Favorite Pesticide

People often ask me about the most dangerous pesticides — the ones which they should be careful to avoid.  There are lots to choose from:  Di-syston (aka disulfoton) is really bad.  Rotenone has some potential problems that make it scary, as does copper sulfate.  But for my money the worst thing out there is something that isn’t even supposed to be used as a pesticide (at least not anymore) but which finds its way into our gardens thanks to recommendations from people like Jerry Baker:  Tobacco.

Despite its obviously “natural” origins, tobacco isn’t allowed by organic growers because of its drawbacks which I’ll mention below, but because it finds its way into so many “how-to” books it’s definitely worth knowing about this beast.

It’s easy to buy chewing tobacco, mix it with a little water, and apply it to whatever aphids or other insects that you see.  What’s even better is that tobacco really does work (just like Jerry says!).  In fact, for some things it works great.  For example, I’ve tried all kinds of barriers against slugs, and tobacco is the one that works the best, hands down — copper is kinda OK, diatomaceous earth takes a while but works fine — but man, tobacco really throws slugs for a loop.  Watching a slug try to go through a pile of tobacco is terrible (and yet morbidly entertaining!)  First, the slug approaches the tobacco at a snails pace (the snail is a close relative of the slug!)  Then the slug touches the tobacco….and then the fun begins!  The slug starts to move really fast — literally mouse walking pace — and then it stops — and then it shakes — and then it dies.  This all happens within four minutes.  The slugs in the picture below are all dead.

Despite my success I have a hard time recommending tobacco for slugs for two reasons.  The first is that it can carry plant diseases which can cause some major problems, and the second is that some dogs like to nibble at the tobacco — and they won’t let you know they’ve nibbled it until you let them back into the house (if you know what I mean)!

When a tobacco spray is used for insects the process is a bit different than just placing tobacco on the ground.  First, you mix tobacco with water, let it soak for awhile, filter the water out, and then spray it on the insects.  In the old days — the 1800s when this type of spray was popular — they would mix about a pound of tobacco with a gallon of water.  Jerry usually recommends much less.  The problem with recommending less than this is that at lower concentrations it doesn’t work nearly as well — but you really wouldn’t want to apply more because then the spray starts to get dangerous (because of higher nicotine concentrations).  So it’s a catch-22.  Don’t underestimate the toxicity of nicotine!  Also avoid underestimating the nastiness of the plant viruses that this stuff carries.

So what should you use instead?  A good insecticidal soap, or a spray with water are what I like to recommend.  If you must use something stronger then look for an insecticide with the active ingredient permethrin and follow the labeled instructions carefully (also make sure that the insect you want to control is on the label — if you can’t identify the insect you’re trying to control, or if that insect isn’t on the label, then don’t use a pesticide).  For slugs my favorite pesticide uses the active ingredient iron-phosphate.

Chad and Jeff’s Excellent Nursery Adventure

About 3 months after I started my job in Minnesota I hired a technician to help me run the nursery and to manage research plots.  His name is Chad and he stands about 6 foot 4, has shoulders that threaten to pop the sides of the skid steer loader whenever he enters it, and he knows his stuff because he needs to (and even if he didn’t know his stuff you’d be scared to tell him that because he looks dangerous with his frightening Fu-Manchu moustache).  Currently Chad is responsible for day to day operations in the nursery as well as writing publications.  In other words he’s indispensible.  When you read a post from me, particularly when it’s regarding nursery or landscape research, you’re usually reading a combination of both of our thoughts.  

Over the years Chad and I have seen a lot of nursery stock; some of it good, and some of it bad.  Between us we’ve seen poor pruning, unhealthy root systems, pot-bound plants, trees planted in soil that was much too alkaline or acidic for them, trees planted in the wrong zone, trees sold that weren’t close to the size that they were supposed to be, trees that were girdled by critters, root systems completely eaten by voles and even a tree shot with a handgun.  I once saw a whole field of Japanese maples topped (basically topping is when you cut horizontally through a trees canopy to give it a flattop – talk about competing leaders and narrow crotch angles!).  Seeing that field almost made me cry – A planting worth $20,000 – $30,000 wholesale almost instantly became worth the price of kindling.  But we agree that none of that can hold a candle to Sara’s Nursery (Named after the owner’s daughter).

I received a call a few years ago from a nursery in western Wisconsin (which, for those of you who aren’t familiar with this part of the world, is much closer to the Twin Cities than to Madison, WI where the University of Wisconsin is).  The caller was very concerned that the plants in the nursery which she had been hired to run were failing.  Basically, their leaves were dropping and she couldn’t figure out why.  This was even happening to plants that we usually consider “indestructible” like potentilla.  I had never heard of such a thing, but it sounded like a soil problem and so I asked her to have some soil tests done and to send me the results.  She agreed, but she was distraught and asked me to come and take a look at her operation.  I balked at first, but after a few minutes of begging I gave in.  I asked Chad if he’d like to join me on a trip to the nursery the next day; he agreed and we were off.

The nursery that we found was a retail operation on a road which was once a major thoroughfare, but had been reduced to a minor highway when the interstate, which ran parallel, had been expanded.  Still, it seemed like a pretty good location for a retail nursery in terms of customer traffic.   After we parked the car Chad hopped out and began inspecting balled and burlapped evergreens while I joined the manager to look at their container stock.  It was a mess.  It was the end of summer when we visited, but the leaf drop made it look as though we were in the late fall.

I popped a potentilla out of a container and could find no roots reaching the containers edge.  Taking a closer look I quickly discovered one major problem.  These were bare root plants planted into containers filled with soil.  Soil is almost never a good thing to put into a container because it’s usually too heavy and prevents air from working its way down to the plant’s roots.  The gentleman who owned the nursery (not the manager – in most cases she just seemed to do what the owner wanted to do) was a farmer who had decided that it made sense to save money by using this soil which grew his field crops so well.   This nursery was buying bare-root plants, popping them into containers filled with field soil, and then selling them at quite a mark-up (by the way, this is considered an unethical practice).

This field soil was obviously a problem, but, while plants usually suffer because of the use of soil in containers, I didn’t think it was likely to cause the carnage that I was seeing.  I asked about their fertilizer and watering practices.  Both of those seemed reasonable and unlikely to cause a major problem.

Meanwhile, Chad came back to report on the evergreens.  Almost all of the evergreens (which showed signs of repeated shearing – good for Christmas trees — not good for the long term health of landscape trees) were missing needles close to the base of the tree and appeared to be suffering somewhat.  I thought it might be a water issue, particularly if city water were being used, and asked where it came from.  The manager told me that all of their water came from a well on site.  In this part of the world we frequently have issues with well water being too alkaline, but it usually doesn’t cause the type of damage that I was seeing here.  I filed water away as a possible, but unlikely cause.

I was pretty stumped, as was Chad.  Obviously we saw problems, but these just didn’t seem sufficient to cause what we were seeing.  The manager offered to show us the potting operation, we followed.  The first thing that struck me about the potting shed was that it seemed old, and yet the timbers themselves hardly showed any rot which is kind of unusual.  We asked when the shed had been built and the manager indicated that she had reason to believe that the shed had been built in the 1940s or 50s.

We entered the shed and noticed a large pile of what we assumed to be soil.  Nothing special.  Then our eyes began to adjust to the dim light and we realized that this was no ordinary pile of soil.  It was mostly white.  We were confused.  The first thought that went through my head was “what is this, cocaine?”  Then I thought, no, it must be perlite.  I looked at Chad.  His eyes were big and round.  I went over to the pile, poked my finger into it, and then touched it to my tongue.

“What the EXPLICATIVE DELETED is this place?” I asked Chad (OK, I may not have used those exact words, but it was something close).  The manager must have overheard.

“Well, it’s a potting shed now, but it was built to store salt for the highway” she responded. “That’s just a pile of leftover salt.  We stack our soil against it when it comes in.”

We tested both the soil from the pots and their irrigation water.  Both were ridiculously high in salt (and, not coincidentally, sodium levels).  In fact, salt levels were high enough in the irrigation water that it would literally burn foliage off of the plants.

Shortly after visiting this nursery Chad became a Buddhist and my beard turned more gray than brown.  I can’t swear that it was this nursery that caused these changes, but I can tell you that I haven’t been the same since.

As Bad As It Gets?

Last week I took a look at old, out of print books that are worth finding and reading.  This week I think I’ll take a slightly different track and instead turn my attention to a book that is currently in print, but which shouldn’t be.  In fact, 1001 All-Natural Secrets to a Pest-Free Property by Myles H. Bader can be found in many bookstores, was actually one of the best selling garden books of 2006, and is still selling today.  There are other books that I have problems with (Jerry Baker comes to mind) but when considering the worst of the worst this book is all by itself.

I was first introduced to Dr. Bader (he reportedly has a doctorate in Preventive Care from Loma Linda University) one night when I couldn’t sleep.  He was on one of those “paid programming” shows talking about homemade cures for insects around the house.  Normally these half-hour long advertisements cure my insomnia, but not this time.  As someone who loves to learn about and test homemade remedies I was mesmerized by his recommendations and quickly ordered the book.  Sure, on the show he seemed to “dumb things down” a little, but here was a bonafied professor who might have some really cool stuff for me to look at!  I couldn’t wait.

After I received the book I discovered that Dr. Bader used the English language poorly.  This didn’t turn me off to the book though.  I’m pretty forgiving of bad English.  I know that mine isn’t the best and there are sections in all of my books which still haunt me.  Still, the sheer number of errors in Bader’s book was staggering.  For example, here’s a paragraph from page 3:  “His interests have always been in the field of food and cooking and many of his books are related to helping the chef or cook with cooking and kitchen secrets that may gave been forgotten over the years.  This has lead him to include household hints and other related subjects in his books.”   (yes, the words gave and lead are used in the book exactly as they appear above).  And this is just the first page with a significant amount of writing!

Still, I didn’t buy this book for good editing; I bought it for cool, “all-natural” cures.  And so I turned the pages hoping to find something useful.  On page 23 I discovered that the insecticide “Sevin” is organic and is composed of pyrethrums and diatomaceous earth (This is completely wrong, the active ingredient in Sevin is carbaryl, a synthetic insecticide).  I also learned, on the same page, that mixing horse manure with hot water, letting the mixture cool, and then spraying it onto fire ants will kill them (What!?!!?).  There are no instructions about how much of the manure or hot water to use.  Other interesting remedies that you should probably avoid include spraying hairspray onto flies to kill them and using a mixture of 1/3 cow manure, 1/3 sand, and 1/3 clay to coat the trunk and branches of a tree infested by aphids (I’m not sure how this would work since most aphids attack the leaves of trees…). At the end of the book there is a glossary where I learned that Rotenone is a low toxicity poison (never mind that this organic poison was recently voluntarily withdrawn by its makers for use as an insecticide at least in part because of safety/health concerns).  Indeed, almost every organic pesticide was treated lightly, apparently simply because they’re “natural” (which, as some of you may know, is a pet peeve of mine).

The interesting thing about this book is that there were a few useful tips, but with so much hooey it was often tough to tease those tips out.  If you’re one of those people who thinks that a book can be so bad that it’s good then you might enjoy paging through this book, but, other than that, I think this book is best used as a doorstop.

And now I have a challenge for all of you.  Does anyone know of a worse book?  (and, if so, where can I buy a copy?)

Old Books

It’s a rainy day in the upper Midwest.  My favorite time to read.  Of course, I should be writing papers, grading papers, or setting up seminars for next semester.  But instead I’m drawn to my bookshelves.  In most professors offices that I visit the shelves are an odd mix of old and new books that focus on the particular subject which that professor works on, along with the scientific journals that relate to that discipline.  It’s no different in my office, except that I tend towards older books and my tastes are just a little bit more eclectic than most.  I have a particular fondness for old entomology texts and I also like books on garden remedies — whether old or new, academic or not.

In a future post, maybe next week or so, I’m going to go down a rogues gallery of books that I don’t care for, old or new.  But today I’m going to do something a little different, I’m going to tell you the three books that I think are must reads for any gardener or horticulturist.  But the catch is that none of these books are currently in print and so you’ll need to search for them or go to Amazon.com where you can often find dealers who have used copies.  These books aren’t listed in any particular order, except the order in which they came to my mind when I put this post together.

Best Reading Book — The World was my Garden, written by David Fairchild, is one of the best horticultural reads of all time.  I’ve heard Fairchild called the last of the great plant explorers as well as the father of modern plant exploration.  Either title works.  I wouldn’t call him the greatest plant explorer of all time (though it’s no stretch to say that he was one of the best), but he is certainly the most skilled writer (at least in my mind).

Best Informational Book(s) — The Standard Cyclopedia of Horticulture edited by L. H. Bailey is a series of three (or more depending on the edition you get) books which is basically a humongous encyclopedia of everything horticultural.  The beauty of these books is the amount of information they deliver along with the appreciation that the writers (and especially the editor who many consider the father of modern horticulture) had for the art and science of horticulture.  So often we, as professors, want to explain things “scientifically.”  Sometimes gardeners just want to talk about horticulture as an “art”.  This cyclopedia does a great job of appreciating horticulture from both sides.  My favorite section is one called “horticulturists” where an overview of some of the greatest horticulturists of all time is offered, one of the saddest being E. G. Lodeman who died young, but not before writing another of my favorite books of all time, “The Spraying of Plants” — which I won’t include here because it’s a book that will only appeal to a very small audience (those who want to know about pesticides used before1900).

Best Book on Insect Control — Destructive and Useful Insects is a classic text on insect control which has seen many editions dating back to the 1920s.  The best edition, at least in my mind, is the 2nd edition.  The second edition of this book was out before the widespread use of DDT and so, while lead arsenate is recommended a little more than I’d like, there are lots of cultural remedies for controlling insect pests listed also.

I’d love to hear about some of your favorite out-of-print books also — anything from general horticulture to plant pathology and entomology — Let me know what your must-haves are!