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If you’re getting sick of the compost tea debate then you can skip this post.  If not, then read on! 

This past week I received my copy of Arboriculture and Urban Forestry 37(6).  And in it, page 269, I discovered an article titled “Laboratory Assays on the Effects of Aerated Compost Tea and Fertilization on Biochemical Properties and Denitrification in a Silt Loam and Bt Clay Loam Soils” by Bryant Scharenbroch, William Treaurer, Michelle Catania and Vincent Brand.  Basically what the authors did was to add dilute compost tea, concentrated compost tea, and a fertilizer to a couple of different types of soil in a laboratory setting to establish how they changed the soil.  To be honest the article was a little tough to read for a non-soil scientist and I found myself looking up terms quite often.  Still, I found their conclusions fascinating.  There were actually a number of conclusions, I’m just going to cover what I think are the most interesting:

1. “Aerated Compost tea appears INFERIOR  [you read that right – inferior] compared to fertilizer in its ability to increase microbial biomass, microbial activity” and a few other things.   Hmmm…I’d been told that microbes hated synthetic fertilizer.  I guess not all microbes agree.  In terms of the fertilizer used, it was a 30-10-7.  I didn’t see it explicitly stated in the article, but I’d bet it was a synthetic fertilizer called Arbor Green Pro.  It was applied at what I would consider a heavy dose.
2. Aerated compost tea, or at least the compost tea tested in this article, did contain a significant amount of nutrients.
3. On the up side for compost tea it was pointed out that compost tea treatments might help a poor soil retain more nitrogen.  Maybe…but the authors also pointed out that “only the fertilizer treatment appeared to deliver enough available nitrogen to potentially meet tree needs in the Bt horizon soils” (in other words poorer soils).  Interesting – but if we just added compost we’d have a better soil anyway, which brings us to the next point….
4. The compost tea tested contained only a small portion of the microorganisms that compost does.

So what’s the take home message from this article?  This wasn’t explicitly stated in the article — in fact I’m not even sure the authors would agree with me — but to me the important message is 1) ADD COMPOST and 2) IF YOU NEED TO ADD NUTRIENTS ADD FERTILIZER NOT COMPOST TEA (though I’d go with a nice renewable organic rather than a synthetic).   

I just can’t resist telling our Christmas tree hunting tradition.

On the Friday after Thanksgiving, we drive out to Monroe (about 45 minutes north of Seattle) to our favorite tree farm, where we look for the perfect noble fir.  Here, Jim demonstrates his dubious taste in trees:

This year, Charlotte brought a tennis buddy home from college. Nasko lives in Bulgaria and wasn’t traveling home for a holiday they don’t celebrate.  So he got to experience the Great Scott Tree hunt for himself:

My son Jack (on the left) complained that he NEVER got to choose the tree (Mom retains veto power over all selections), and happily for all of us this year he picked the winner:

Jim does the cutting, and the kids do the carrying:

This tree farm also has hot chocolate and candy canes, which we all enjoy before returning to town (Monroe that is) and having lunch at the local Taco Bell. It’s a tradition that started when the kids were littler and you don’t mess with tradition.

Needless to say, we will ALWAYS have a real tree.

My post on Christmas tree safety got blog readers Michael and Thad into the never-ending debate of what’s better for the environment: a real Christmas tree or a fake one.  As is often said: “Where you stand depends on where you sit.”  In the interests of full disclosure I will admit my bias is on the real tree side.  My first job in high school was shearing Christmas trees back when minimum wage was $1.65 /hour (1976).  Also in the interest of full disclosure I work closely with the Christmas tree growers in Michigan and elsewhere and get a small amount of research support from the state grower’s association.  

Michael and Thad’s discussion turned pretty quickly to the bottom-line when it comes to carbon footprint.  Which choice looks better depends on the assumptions you are willing to make.  The critical ones, of course, are how long do you keep a fake tree and how far do you drive to get a real tree.  If you buy one artificial tree and keep it 50 years it replaces 50 real trees.  If you buy a real tree from a tree lot that’s on you way home and don’t make a special tree to get it, the real tree comes out looking good.  The American Christmas Tree Associate (a trade association for artificial trees, NOT a growers’ group) has commissioned a life cycle assessment and claim the carbon footprint question is a wash  http://www.christmastreeassociation.org/Article%20Pages/choosing-an-artificial-or-real-christmas-tree   This is in contrast to some earlier claims they had made the artificial trees were greener – based largely on the distance driven to get a real tree.

One thing to note is that there are other environmental impacts besides carbon emissions to consider.  Artificial trees are typically made from non-biodegradable plastics and most Christmas tree plantations require some pesticide and fertilizer inputs to keep trees looking good.  In many parts of the country Christmas tree plantation can provide habitat for certain types of wildlife, especially birds that use the trees for perches and nesting.  

Hannah and I embark on Tree-hunt 2011…

While everything seems to get boiled down to carbon comparison these days there are certainly more things to consider.  For those that buy a tree at a local ‘choose and cut’ farm, there is certainly the satisfaction that at least some of your holiday purchases are supporting the local economy.  At the end of the day, however, the debate between real vs. fake for most people gets down to one of two factors: tradition and convenience.  Even though my heart is on the real tree side, I can’t deny that pulling an artificial tree out of a box from the attic each year is easier than going out on a cold wet, December day and getting a tree from a farm and then bringing it home and setting it up.  But my mom was German and we always had a real tree in the house when I grew up.  Now that I have my own family, my daughter and I have a tradition of going out to a local Choose and cut tree farm and looking for the perfect Fraser fir.  No artificial tree can ever replace that. 

Fraser firs at Daisy Hill farm.  Still got a couple years to go, but eventually I’ll be cutting my own.

Over the years I’ve gotten a lot of questions about how to compost.  I’m not a composting expert, and don’t want to pass myself off as one, but I do understand the basics and I like to think of myself as a proponent of composting.  Having said that, there is a composting practice which I’m asked about frequently that I never know quite how to answer.  Should you put meat into your compost?

The easy answer to the question of whether meat belongs in compost is that it is an organic material which will break down just fine along with all of the vegetable matter in your compost.  But there’s more to it than that.  I’ve been to some areas that specifically forbid meat in compost because of the vermin that it will attract.  And it’s true, at least to some extent, that meat attracts vermin.  Rats, raccoons, and other mammals will go after meats.  It’s the high protein content.  How can they resist?  While leaves and grass can have as much as 4% nitrogen, meats will typically have between 5 and even as high as 16% nitrogen.  Of course they go for it! 

Besides the vermin issue, if raw meat is placed in a compost pile it tends to stink, especially if it isn’t mixed into the pile.  Cooked meat (table scraps) breaks down a little bit more slowly than raw meat and doesn’t stink as much.  Because of the high nitrogen content of meat it will get a compost pile to compost a little bit faster.  Personally, I’m in favor of using meat in compost piles as long as you’re careful to turn the pile frequently to keep it inside the pile where it can’t do as much harm.  If you’re a casual composter then you might want to avoid using meat because of the potential problems.  So there it is – in my mind the answer to whether you should put meat in compost or not comes down to how closely you like to monitor your pile, whether there are laws against it in your area, and also the likelihood of mammals getting into it where you live.  Also, at most meat should be a small component of a compost pile — not the main component.

I’ve been teaching plant physiology or related courses for a long, long time, and one of the tenets is that woody plants don’t heal.  In contrast to animal tissues, when trees and shrubs are wounded the damaged tissues are permanently destroyed.  Wounds are compartmentalized and covered with wound wood.  Arborists are fond of saying "plants seal, not heal."

That’s all fine and good for woody plant parts, but what about grafts?  Since grafting reconnects cambial and phloem tissues, is this "healing?" And what about nonwoody plants, like annual flowers and vegetables? 

Oddly, this type of information is sadly lacking in physiology textbooks, but it’s a question that I get routinely from gardeners.  And it’s not just an exercise in semantics.  People make some poor choices in treating tree wounds, for example, laboring under the false impression that such wounds should be treated with wound paint or bandages so they can "heal."

(with apologies to Blue Oyster Cult)

‘Tis the season for all things Christmas, including the annual hysterical reports of the dangers of real Christmas trees.  Along with heartwarming reports of Thanksgiving feasts at the local homeless shelter and live remotes of frenzied Black Friday shoppers, footage of Christmas trees going up in flames seems to be a staple of every network affiliate in the country.  In fact, in some cases the intrepid reporter will go to great lengths to insure that the Tannenbaum ignites the obligatory conflagration http://www.youtube.com/watch?v=P9dNS5WPncU

What the talking head doesn’t want to tell you is that a fresh, well-maintained Christmas tree is very difficult to ignite.  Numerous fire agencies and others have documented that a fresh tree that is kept watered will self-extinguish even if exposed to direct flame.  And faulty wiring is even less likely to ignite a fresh tree.  The story changes completely, however, if trees are allowed to dry.  http://www.youtube.com/watch?v=RNjO3wZDVlA

Of course, dry trees drop needles as well. So the key to keeping your Christmas safe (and tidy) is to get a fresh tree and keep it watered.  For many trees this means checking and re-filling the water daily, especially during the first week when the tree is brought in the home.  It’s not a real Christmas without a real tree – make sure it’s a safe one as well.  

So far a mild fall has lingered here in mid-Michigan.  With temps in the mid-50’s I was able make much more headway on my fall clean-up than usual.  Typically we get enough early snows or cold-damp November gales that I don’t get to the last of the leaves and frosted hostas until spring.  Leaves are especially challenging here at Daisy Hill farm.  We have about dozen hardwood trees, mainly oaks and hickories, that drop a sizable load of leaves each fall.  For the leaves that fall in the lawn I follow Jeff’s practice and work them into the grass with the mower.  But that still leaves the leaves in the beds and every other nook and cranny they can find their way into.  Then it’s time to pull out the rake and my Craftsman 7.5 hp chipper/shredder; aka ‘My best friend’ (cue Harry Nilsson singing the ‘Courtship of Eddie’s Father’ theme).  I bought the shedder 8 year’s ago and it’s worked like a champ.  The manufacturer claims a 16:1 volume reduction and I’d say that’s a reasonable estimate.  My usual M.O. is to rake leaves, dead perennials, even small twigs into a series of piles and then work my way around the yard.  The main things to avoid are rocks (of course) and plants with long fibrous stems such as tomatoes, which can wrap around the impeller.  In a bit of serendipity, the original bag that came with unit finally wore to tatters so I ordered a new one from Sears on-line.  The new bag actually goes to a newer model and is almost three times the size of the original.  Having to continually empty the bag had been my biggest complaint about the system, so I’m in leaf shredding heaven now.  Since the oak leaves predominate I use the shredded leaves as mulch, putting down about a 1” layer each fall on tree and shrub beds.  It has a nice, natural appearance.  Plus it’s about 1% nitrogen.  Not a huge number, but a good way to recycle what nature have given us.  And certainly better than burning (or attempting to burn) leaves, which is still the most popular disposal method in rural Michigan.

Back in 2006, when I first started garden writing, I was invited to give a talk in Michigan.  It was really exciting to get this kind of invitation so early in my writing career and I was thrilled to have the opportunity to talk to an audience that wasn’t composed primarily of students or academics. 

Looking back at those talks…well…they weren’t particularly good.  Sure, there was good information, but I wasn’t particularly comfortable giving talks at that stage and so I’m not sure I got my information across nearly as well as I should have. 

After my talks there really wasn’t much to do besides listening to other speakers, and so that’s what I did.  That’s where I got to listen to Jeff Ball, a garden writer and self-proclaimed yardener.  I was amazed at how this guy filled the room with people who wanted to hear him speak and further amazed at how well he spoke.   Being in academia I’m always surprised when someone speaks without visual aids – I had always idolized Michael Dirr, my former advisor and one of the greatest speakers I know, who always played off of his magnificent slides of plants.  I really had never seen anyone give a talk without slides, or overheads, or powerpoint, or a chalkboard, before.  But Jeff Ball did a talk right off the top of his head with nothing else, and he was magnificent.  I remember not agreeing with everything he said (can’t remember what specifically), but more importantly, I remember how the tone of his voice and his wonderful sense of timing and rhythm kept the audience interested and engaged.   After that day there were two speakers who I idolized, Mike Dirr and Jeff Ball. 

Jeff Ball passed away this past week.  It’s always sad when someone who you know and admire passes, but their passing also provides a time for you to think back on the good things which they did.  I didn’t know Jeff well at all.  Indeed, I never saw him speak again after that day.  But his talk was inspirational and led me to really think about how I give a presentation, and for that I can’t thank Jeff enough.

“Stealing an idea from one source is plagiarism; stealing from many sources is research.”  This quote has been attributed to so many people I won’t bother trying to list them here.  But the point is a lot of what we do as professors is spend our time digging into the literature to look for substantiating or conflicting evidence for the ideas were interested in testing.  As a grad student back in the 1980’s, a time-honored tradition was to spend the afternoon at the library combing the stacks for journal articles, loading volume after volume onto a cart and then schlepping off the library copy center.  With the mechanical hum in the background and green glare of the scanner radiating off the walls, we’d wear our toner smudges like a badge of honor as the copy machine counte kept track of our progress.

Today, of course, things have changed dramatically.  The hardcopy CAB abstracts have been replaced by Google Scholar and Web of Science.  For those of us at major universities, hundreds of journals are available at our fingertips through on-line subscriptions through our libraries.  And an electronic interlibrary loan request can usually produce a .pdf of even the most obscure reference with a couple of days.  Unfortunately for those of us working in landscape horticulture some of the hardest to find journals were the ones that we often wanted most.  For example, journals from the American Society for Horticultural Science (ASHS) were only available to members and just recently became open access and indexed through Web of Science and other indexes.  Fortunately the situation is improving for two other sources that contain the type of applied research we are often after.  Arboriculture and Urban Forestry (formerly Journal of Arboriculture) and Journal of Environmental Horticulture are both available on-line (or partly available on-line).  More importantly for GP blog readers, neither requires a subscription or university log-in.  

Arboriculture and Urban Forestry is available at http://auf.isa-arbor.com/ 

Journal of Environmental Horticulture is available at http://www.hriresearch.org/index.cfm?page=Content&categoryID=174

Both journals include a search function to make it easier to find related articles.

Yesterday I happened to see a garden calendar encouraging people to pick up their leaves so that they don’t pollute streams and lakes by encouraging algae to grow.  This was a good idea, I thought, but then I started to wonder whether leaves on the lawn might not be a better idea?  After all, the reason that leaves cause algal growth in water is because of the nutrients they have.  And if they have nutrients couldn’t those be used for fertilizer instead of the regular fertilizers which we use?  What if we raked all of our leaves onto our yards?

There’s no denying that leaves which drop in the fall can make great compost, but how well would they work as a fertilizer? So I did a little bit of preliminary research — reading old papers and such — and here’s what I’ve come up with:

Fallen leaves are very variable in nutrient content.  Some leaves have 1% nitrogen, and some can have almost 3% (these are mostly from leguminous trees).  In terms of phosphorus, fallen leaves tend to have around 0.1%, though once again, it’s very variable.   For the purposes of this post I’m going to stick with nitrogen.

For 1,000 square feet of grass yard it takes about a pound of nitrogen per year to fertilize, even with a low input variety.

In a heavily wooded lot it wouldn’t be odd to have around 100 pounds of leaves fall in a 1,000 square foot area.  At 1% nitrogen, the leaves would provide enough nitrogen for the grass, but that would probably end up being a moot point because the leaves would have a good chance of smothering the grass. 

So what I’m wondering is, if we planted trees which were legumes, and had higher levels of nitrogen, and if we chopped up the leaves so they weren’t as likely to smother the grass (using a lawnmower or whatever) could we provide enough nitrogen per year for a healthy low input lawn?  Personally, I think so.  We would need to keep these leaves off of driveways and sidewalks because this is where they would do their worst in terms of contaminating water, but if they were just in yards — I think it might work.