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It recently came to my attention that the Sierra Club published an article on a new system for reducing watering in lawns.  You can read it here.  Basically what the company, AquaCents, does is inject a polyacrylamide gel into the landscape and then the gel supposedly collects irrigation and/or rain water and releases it for plants to take up as the landscape dries.

I think it’s a good concept, but I’m highly skeptical that this is a good product for two reasons.  The first is that I’ve used polyacrylamide gels to hold water for plants before and have found no benefit.  In fact, most papers out there on the topic show either no benefit or marginal benefit from using these gels in terms of increasing the amount of water available to plants – though I must admit that results are variable.

Please note that I didn’t say I was skeptical that the polymer will hold lots of water – I’m not.  It will hold lots of water.

Which leads us to an important question.  If we know that the gel will hold water, and this company has done testing which shows reduced watering is required in lawns that use this technology, then why am I skeptical?

Based on what I have read and the experiments I’ve done, I think the company’s testing isn’t telling the whole story.

As far as I can tell, what they’re doing to test this product is injecting it into lawns and then allowing a moisture detector in the lawn to trigger sprinklers to go on when soil moisture falls below a certain level.  If you test one lawn with the polymer side by side against another lawn without the polymer, then the lawn with the polymer will use less sprinkler water because the gel holds more water than the surrounding soil – meaning that it stays more moist. So at this point it sure seems like the gel is a good idea — right?

No, because this experiment asked the wrong question.  It looked at how much water was in the lawn, NOT HOW MUCH WATER WAS GETTING TO THE PLANT.  And that’s what we need to know – how much water gathered up in that gel will actually get to the plant.  What I’ve found in my work is that having water in the gel is not the same as getting water to the plant.  The gel seems to hold the water too tightly for the plant to get it.  It’s a little like having an impenetrable safe filled with five million dollars in gold.  Sure, the gold is there, but if you can’t get to it, who cares?

So, why does the grass seem to be growing more roots when the gel is used?  My best guess is that the lawns were overwatered in the first place and the gel just provided a way for homeowners to decrease their watering.  Let’s face the facts, overwatering of lawns is rampant.

But I mentioned that there were two reasons why I didn’t like the gel.  I named the first, so what’s the second?  It’s something that I saw on one of Linda’s sites a few years ago and then looked into a little further.  Polyacrylamide gel, while relatively safe in and of itself, may break down into more toxic substances.  See Linda’s article here.

Finally – and this is just a thought — there are plenty of other absorbent materials out there that might be injected into the ground, including some made of starch – I have tried gels made of starch and have found them to be as effective as those made of polyacrylamide (though I know that’s not saying a lot).  Or…maybe we should just water more judiciously.  Like I said, just a thought.

I recently spotted this in the window of a toy shop:

Recommended for ages 10 and up. My youth was apparently misspent with Hot Wheels and model horses (and collisions thereof).  I could have been getting a step up on grad school.

"See genetic material with your
own eyes as you isolate the DNA from a tomato in a test tube." (This is actually fun and easy and you don’t need a kit to do it.)

"Learn about dominant and recessive genes and play inheritance
games to determine how traits will be expressed."  Then you can blame the correct parent for your near-sightedness, flat feet, etc.

"Breed your own bacteria colony to experiment with survival of
the fittest."  Now, we’re talking!!!  I would have loved this.  My mother, however, would have argued that the disgusting storage space under my bed was, in fact, a giant petri dish.

Just flew in from Miami and boy are my arms tired – rim shot.  Seriously, I just returned for the annual meeting of the American Society for Horticultural Science (ASHS) in Miami.  Always good to wander the halls and renew old acquaintances and take in the latest in Hort science.  Judging by the posters and talks here are some of the hot topics at this year’s ASHS meeting.

LED’s
Horticultural applications of Light Emitting Diodes (LED) are receiving a lot of attention these days.  There are a couple of reasons for this. One, costs of LEDs are decreasing as manufacturing becomes more efficient.  Two, LED’s can be built to generate specific wavelengths of lights.  As many folks learned in biology, plants only use specific wavelengths during photosynthesis.  Therefore LED’s can be used to only produce the light energy that plants need for photosynthesis – this can greatly increase energy efficiency.  Aslo, incandescent light bulbs are being phased out of production.  Old fashioned bulbs are not very efficient (they yield about 10% of energy used as light) but the light they do produce is effective for things like phot- period lighting (i.e., daylight extension for greenhouse crops).  Since LED’s can be designed to reproduce the same wavelengths using much less energy, they may ultimately be a good substitute for incandescent bulbs.

High tunnels

Lots of interest these days in ‘high tunnels’ for fruit and vegetable production.  These are not full-blown greenhouses but simply tall hoop-house structures big enough to grow fruit trees inside.  One of the main benefits is season extension; allowing fruit or vegetable harvests earlier or later in the season than would be possible otherwise.  This is especially important when we consider the local food movement for colder climates.  There are also other, less obvious, benefits such as eliminating cracking of cherries due to rainfall.

Sensor-based irrigation systems

A hot topic, especially for the nursery crowd.  There have been rapid advances in the reliability of capacitance probes and while costs are decreasing.  In addition, there have been advances in wireless control systems.  There are still challenges for nursery growers that have to deal with a diverse array of crop types and container sizes but researchers are definitely on the path of developing sensor-based systems that will automatically turn irrigation on and off in response to real-time soil moisture measurements.  This will help to optimize plant growth while minimizing potential leaching of nutrients and chemicals.   

One of the recommendations that I always make when I discuss organic methods that work is bagging fruit.  If you’ve never heard of it then here’s the story.  By placing a bag of some sort around your fruit, such as apples or peaches, when they’re young you can protect them from insects and disease.  I used to recommend plastic ziplock bags (up here in the North anyway), and I still do, they’re cheap and work well.  You can also purchase Japanese fruit bags that will work.  But recently I was introduced to a more streamlined product which I really like — a cloth pocket with a cord to close off the top.  Since it’s made out of cloth it probably won’t protect against disease as well as plastic bags or Japanese fruit bags, but if insects are your main concern then I think these might be just perfect for you — if you don’t mind paying a few dollars for them (they are reusable!)

At a master gardener conference I recently attended one of the vendors handed me some of her Startbagging fruit bags to test on tomatoes.  I say test because, while these bags have been pretty effective at protecting tree fruits, they haven’t been used much for veggies (OK, OK, a tomato is technically a fruit).  To be honest though, I’m not as worried about insects on tomatoes as I am deer.  The deer near me don’t seem to care for the plants themselves, but they just love to pick the tomatoes off when they’re almost, but not quite ripe.  Jerks. 

Here are a few bags on a tomato plant.

Here’s a closeup of one of the bags.

I’ve only had these bags on the plant for about a week now — so far so good.  The company producing these bags is a small start-up.  From what I understand these bags are patent pending.  I wish this company well because I think this is organic pest control at its best — reusable products that don’t utilize chemicals.  If you have any interest you can go to startbagging.com to take a look (the website is a little basic right now — hopefully they’ll fix that soon!).

Just a little bit of show and tell today.  The week before last the Central Region of the American Conifer Society (ACS) hosted the National ACS meeting here in Michigan.  Over 300 conferites gathered to discuss their favorite plants and share their conifer addiction.

The highlight of the meeting was a field trip to the Harper Collection of Rare and Dwarf Conifers at Michigan State University’s Hidden Lake Gardens.  The Harper collection, which was donated to MSU by noted plantsman Justin ‘Chub’ Harper is a world-class assemblage of conifers and includes over 550 plants displayed in a wonderfully-designed layout.

To add a little fun to the outing, each ACS member was give three pink pin-flags and asked to mark their three favorite conifers.  Tough to choose just three from this collection. 

ACS members descend on the Harper Collection

Adrian Bloom adds his vote to Metasequoia glytostraboides ‘Gold rush’

The elephant tree. Pinus strobus ‘Pendula’

Got my vote but wasn’t the winner: Taxodium distichum ‘Pendens’.  If the meeting had been in October when this tree is in fall color, this would have won hands down.

And the winner is… Abies concolor ‘Blue cloak’

Linda’s posting this week made me nostalgic for some good old garden guru advice, so I couldn’t help but zip on over to Jerry Baker’s web site (www.jerrybaker.net) to see if he had anything interesting to tell me.  I wasn’t disappointed!  Here is one of his recommendations:

Three-minute eggshells

“Place eggshells in the microwave for three minutes, remove, crush into a fine powder, and place them in a cloth sachet. Then drop the sachet into your houseplant watering can to give your indoor plants a nice nitrogen-boost.”

Wow! how about that! Eggshells for a nitrogen boost!  Who woulda thought….  Anyway, after I saw this, I got to thinking, maybe, just maybe, there might be some nitrogen there…..

So I microwaved four eggshells, crushed them, and put them into a half-liter of water, then let them sit in the water for about 9 hours.  Then I filtered the water off and ran that water (along with a control sample) over to our soils lab to be tested.

And wouldn’t you know it?  That water DID have nitrogen in it!  About 5 parts per million!  Which is about 1/10th of what I would consider even close to a fertilizer application….So then if we do the math, that would mean that eighty egg shells per liter (about a quart) would make a decent shot of nitrogen.

Sorry Mr. Baker, I just don’t eat that many eggs.

In prepping grad students for their first big talk at a scientific meeting I always tell them everything will be fine – until the first data slide hits the screen.  The audience will nod knowingly during the introductory comments and even during the materials and methods, but data charts and tables are to scientists what chum is to hungry sharks.  So clearly I should have known better than to post figures without error bars in last week’s post.  In my defense, SigmaPlot, my program of choice for scientific graphing, currently resides on my old laptop which is running slower than molasses, so I did the ‘quick and dirty’ and used PowerPoint on my desktop.  Yes, my mother did raise me better than the present a measure of central tendency without an indication of dispersion.

So, duly chastised and humbled, I present the latest (July 12) volumetric soil moisture values from the SoMeDedTREEs.  N=8 for all means *=means are different at p=0.05.  The table below is more complete than last week’s post, which only presented the means from measurements just outside the container root ball.

Mean (std err) volumetric soil moisture of planetrees at MSU Hort farm, with and without 3” of ground red pine mulch

Inside container ball			MC%	std. err.
	15 cm	Mulch*	10.7	1.9
		No	6.4	0.6
	45 cm	Mulch	10.6	1.5
		No	10.5	1.7
Outside ball
	15 cm	Mulch*	21.9	1.3
		No	16.7	0.7
	45 cm	Mulch*	26.1	0.9
		No	23.1	0.9

As I noted a few posts back, this summer marks the 10^th anniversary of the discovery of emerald ash borer (EAB) in southeast Michigan.  While a lot of progress has been made on many fronts in the battle against EAB, the outlook for ash trees in North America still looks bleak for the foreseeable future.  Ash trees, both green and white ash, were popular choices as street and landscape trees throughout the Midwest and elsewhere.  In Michigan ashes comprised up to 30% of the overall tree cover in some communities.  Like chestnut blight and Dutch elm disease, EAB provides a cautionary tale of the destructive potential of invasive pests.  As global trade continues to increase (and the potential for exotic pest movement along with it), the most practical defense in the near term is to spread the risk and increase species diversity.  In spring 2003 Bob Schutzki and I installed an ash alternative species demonstration at the MSU Tollgate Extension Center in Novi, MI, near the epicenter of the EAB infestation.  As we near the completion of the 10^th growing season of the planting we can take stock of some of the better selections.

Dana (R) and Aniko assess the lindens

Hophornbeam Ostrya virginiana


Hardy rubber tree Eucomia ulmoides


Northern pine oak Quercus ellipsoidalis (R) can maintain good leaf color even when soil pH turns Q. palustris (L) chlorotic.

American Sentry linden Tilia americana ‘McKSentry’

Baumannii horsechestnut Aesculus hippocastanum ‘Baumannii’

State street maple Acer miyabei ‘Morton’

Thanks to our partners!

Over the weekend our blog was inaccessible.  The server room in Pullman (where this blog is housed) overheated and everything was shut down.  I apologize to those of you who tried to comment and/or post.  Things are back to normal, at least for the time being.

To those of you who don’t like Blue Oyster Cult, I’m sorry, I just couldn’t stop myself.

A couple of weeks ago I mentioned that I spend some time flame weeding.  It’s a technique for getting rid of weeds by frying them using a 500,000 BTU (I’m not kidding – that’s how powerful this thing is rated) torch hooked up to a propane tank.  It’s not something I do a lot, just something that I get the urge to do periodically — when I need to feel macho.

Here’s the blow by blow – it’s kind of a good news, bad news story.

 

a Good news – Igniting the propane torch was quick and straightforward process.  The torch lit on the first try!

 

Bad news – Here’s my hairless finger after igniting the torch.  Even though the process of igniting the torch was quick and easy, I still burned all of the hair off of the fingers on my right hand. The black dots are all that’s left of my fantastic finger fuzz.

 

Good news – Damn but I feel powerful using this thing!  It’s like holding a jet engine in your hands!  Yes, it does make me feel macho.

 

More good news – only a couple of days later the plot looks almost spotless!

 

Bad news – Two weeks later the perennial weeds are already on their way back.  The ground insulates the roots too well.