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Our visiting GP takes on fertilizers

Like many readers of this blog, I’m like a kid in a candy store where plants are sold.  I try to justify the extra cost of a large annual pot instead of a scrawny 4-pack, or I imagine I’ll find room for that lime green Heuchera and my wife will learn to love it.  But unless I keep my blinders on and stick to the shopping list, I’ll probably leave with a fertilizer.  This year, I’ve purchased 12-0-0, 5-6-6, sulfur, and some 5-1-1 liquid.  Those go with my 6-9-0, 11-2-2, 9-0-5, 2-3-1, and 4-6-4.  I can explain why I ‘need’ each one.  I have a decent idea what my soil is like because I’ve had it tested (though I’m due for another test). But I’ve always questioned how those bags of fertilizer can know exactly what my garden needs.  The rates listed on the bag imply they’re universal under all circumstances and will give great results if the directions are followed.   Is that true?   And at what cost?

For example, 2 of the bags are listed as ‘lawn’ fertilizers (the veggie garden doesn’t care about that though).  But if I apply these to my lawn at the rate listed and 4 times per year, I’m adding 3-4 pounds of nitrogen per 1000 ft2.  That’s a reasonable rate if I irrigate and bag my clippings, but I don’t do either.  Therefore, I only need ~1 pound of nitrogen, not 3 or 4 (see this publication for more info). I just saved myself some money by disobeying the bag. That extra nitrogen isn’t useful for making MY lawn healthy.

One of my fertilizers is labeled ‘tomato’.  If I do exactly as the bag tells me for tomatoes, I would be applying the equivalent of 400 pounds of nitrogen and almost 500 pounds of phosphate per acre.  So what?  Well if I look at a guide for how to grow tomatoes commercially, I’d notice that the recommended nitrogen rate is 100 to 120 pounds per acre, and phosphate is 0 to 240 pounds per acre.  Yes, those are commercial guidelines, but they shouldn’t be too far off from garden recommendations. And of course, recommendations should always be based on soil tests.  But 4 times the N and 2 to infinitely more times the amount of phosphate than is required? That’s likely a waste of money at least. And yes, those recommended guidelines are real: you CAN grow food without adding phosphate or potassium-containing fertilizers.  If the plants you’re growing don’t need much and your soil has plenty, you don’t need to add any.

Say I’ve got an acre of onions (Fig. 1; not quite an acre). One of the bags of fertilizers, were I to follow its instructions for fertilizing ‘vegetables’, tells me that I should add 100 pounds of nitrogen and 120 pounds of phosphate and potash at planting (per acre), followed by half that partway through the season (next to the row). The commercial production guidelines tell me that the nitrogen rate is similar to what the bag of ‘vegetable’ fertilizer says, but I actually need about 7 times less phosphate and potash (based on my soil test results; I have quite a bit of P and K already in my clay-loam soil). I don’t want to add stuff my soil doesn’t need, so I use my shelf full of bags, a scale for weighing pounds of fertilizer per cup, and some math to come up with a custom fertilizer regime that suits my soil and the onion’s needs (see Table 1, and remember that the numbers are for MY soil, not necessarily yours).

One problem with using extra fertilizer may be in the extra cost (wasting nutrient the plant won’t use), but that depends on what fertilizer it is and how much it costs. Another problem may not be immediately apparent, and that is nutrient deficiencies. Too much phosphorus can cause zinc deficiencies, for example. Excesses of some nutrients can create greater chances for pest and disease problems. One big problem with using too much is the potential for these extra nutrients to go where they shouldn’t be, like in groundwater, rivers, lakes, and streams. And as Jeff has mentioned, phosphorus fertilizers won’t be around (cheaply) forever.

Do the work of figuring out what kind of soil you have and what’s in it, what your fruits and veggies need, and what kinds of fertilizers can do the job for you.  Heck, you can even organize your fertilizers based on “cost per pound of nitrogen” to see where the best bang for your nitrogen buck will be.  But none of us are THAT obsessed about our fertilizers, right?…. [$ per bag / (pounds per bag * (% nitrogen/100))].

As a reminder, the numbers on your fertilizers are percent nitrogen, phosphorous (as ‘phosphate’, P2O5), and potassium (as ‘potash’, K2O).  One cup is 16 tablespoons, and an acre is has length of one furlong (660 feet) and width of one chain (66 feet), or 43,560 square feet.  Side rant: metric rocks.

Safety first?

I was driving around town recently and saw a tree service crew clearing up some storm damaged trees. Because of my line of work I usually do a little rubber-necking and try to assess why type of tree came down and what issues may have preceded it’s demise. In this case, however, I was struck not by the trees but by the tree crew. What I saw left me speechless. Well, here, see for yourself…

 

No eye protection.  No hearing protection.  No sign of a hardhat, face-shield, or chaps by the chainsaw.  No personal protective equipment anywhere as near as I could tell.  Of course the photo illustrates a lot of what’s wrong with the landscape and tree service industry.   Economists tell us that this industry has a ‘low barrier to entry’; in other words any one with a chain saw and a pickup truck can put an ad in the classifieds and call themselves a tree service.   As a consumer, you may not care if the employer makes their employees where personal protective equipment (PPE).  But if they don’t care about their employees’ safety, what else don’t they care about?

 

Periodically I’ll write an article for a newspaper or other media on selecting an arborist.  I always make the point that you get what you pay for and urge consumers to compare bids and companies carefully.  Truly professional tree services have to cover the cost of hiring and retaining quality employees, worker training, proper equipment (including PPE), and insurance.  If you skip over those things, like Fly-by-night tree service here, it’s probably not too hard to come out with the low bid.

Science Education and Lichens

Seemingly once a week we see a report in the news about how Science and Math education in the US lags behind many developed countries around the world.  http://articles.cnn.com/2011-05-15/us/education.obrien.response_1_math-and-science-national-robotics-competition-education?_s=PM:US

While we typically think of Chemistry and Physics when discussing science education, biology is in there too.

 

I bring this up because I am continually amazed at how little many people know about basic biology.  Some of this funnels its way into extension calls and e-mails.  A couple of weeks ago I got a call from a distraught homeowner in a Detroit suburb.  “My maple trees are dying”, he told me sincerely.  “There are growths all over them.  They’re big trees.  What do I need to do to save them?”

 

I tried to get as much information as I could over the phone: How old are the trees? What kind of maple? Describe the site.  Describe the symptoms.  I told him the problem didn’t sound like typical issues with maples in our area (i.e., not manganese chlorosis, tar spot, gall mites, or verticillium wilt).  Diagnosing problems sight unseen is difficult so I asked if he could get me some digital photos.  “Yeah, my son has a digital camera.  We can do that.”  Later that week I got a series of digital photos like the one below.

Lichens on maple

I informed him the growths on the trees were lichens, a combination of a fungus and algae; they’re normal and they don’t harm trees.  I gave him a quick biology lesson on lichens and pointed out that some of the pictures he sent were of lichens growing on the sidewalk.  The algae part of the lichen is photosynthetic so they just need a place to hang out – a tree, a sidewalk or a piece of wood all work fine.

British soldier lichens

One of my all time favorite bumper stickers says, “If you think education is expensive, try ignorance”.  I suspect if this homeowner had happened to call an unscrupulous tree service instead of MSU Extension, they would have been more than happy to ‘treat’ the problem and sign him up for their deluxe 8-step pest and micro-nutrient maintenance plan.  Sometimes a little knowledge can go a long ways.

Creating a sense of place

As many GP readers know I’m originally from Olympia, WA.  Once a week or so I troll through the on-line version of my hometown newspaper, the Daily Olympian (“the Daily ‘O’” for short or, more commonly, “the Daily Zero”) to keep up with latest happenings back home and to see if any of my high school classmates are on their way to jail.  While none of the Olympia High Class of ’78 made the news recently, my interest was piqued the other day by the headline “Saving the world – from weeds”.  The article described the Earth day efforts of local grade-schoolers to eradicate Scotch broom from a local nature trail.

http://www.theolympian.com/2011/04/23/1626461/saving-the-world-from-weeds.html#storylink=misearch

 

For those that are not familiar, Scotch broom is an exotic shrub that commonly invades disturbed areas throughout the Northwest.  It’s been a problem for years and, even as a kid 40 years ago, I remember every cutbank around town covered with the nasty yellow blossoms.  In doing a little trolling on the internet I was surprised (stunned is probably a better word) to learn that there are parts of the country where Scotch broom is still sold as an ornamental shrub – named cultivars and all.  There are commercial cultivars of dandelion after all, so why not?

 

As we’ve noted here on the GP blog, there are lots of layers of complexity to the native/non-native discussion.  In many cases I think native advocates have over-sold the ecological side to the argument.  But the Daily O article got my dander up; not because 4th graders were pulling up Scotch broom – good riddance and keep up the good work kids – but because the Scotch broom was replaced with trees and shrubs that were all exotics in that part of the Northwest.

 

Native plant advocates often downplay the ‘sense of place’ argument in promoting natives.  I suppose they feel the ecological arguments are based on ‘harder science’ and therefore more convincing.  While it can be argued that native plants have adapted to the environment in which they evolved; it’s not always a given that the native conditions still exists, particularly in the built environment.  What’s beyond argument, however, is that trees and other plants provide a connection to the natural world around us and, for lack of a better term, do give us a sense of place.  From my personal experience, I have a visceral reaction to the sight of Scotch broom or English ivy in the Northwest where I’m native.  Here in Michigan, on the other hand, I’m less bothered by exotics – even some that may be considered invasive.  I suspect many native-born Michiganders have the opposite reaction.

 

I’m sure part of my connection to all things Washington stems from lessons learned in school (I still know all the lyrics to ‘Washington my Home’ and my plant collection form Mr. Chance’s high school Botany class is still somewhere in the attic of my parent’s house).  Which is why I was flummoxed by the schoolkids planting tulip poplars and sequoias instead of big leaf maples and western redcedars. Wouldn’t this exercise have been a great opportunity to teach these young people about the great trees and shrubs that are native to the Northwest and to give these kids a sense of place?

This ‘n That

Grading finals, looking at roots, and planting seeds is consuming my time this spring, but I have just a few things to share today which might be interesting.

So, as those of you who follow this blog know, I love peanuts.  This year we’re planting out a bunch of new varieties, a few of which are extremely interesting.  Believe it or not there are not only red and pink peanuts but also black, white, and mottled peanuts.  We have these on order — when they come in I’ll post a picture.  When we introduce Minnesota Boiled Peanuts at the State Fair in a few years (that’s the goal anyway) the plan is to introduce a wide variety of really unique looking peanuts.  Fingers crossed they can live here!

Here, at the University of Minnesota, we do a really great job of telling people that, when they fertilize their grass, they should keep the fertilizer on the grass and not on the sidewalk — SO WHY CAN’T THE UNIVERSITY TEACH THE KIDS WHO APPLY THE FERTILIZER TO THE UNIVERSITY’S LAWNS TO KEEP THE DARN FERTILIZER OFF OF THE PAVEMENT?!?  Last week as I walked in I heard a crunching sound coming from my feet.  When I looked down there was a little pile of fertilizer on the sidewalk.

Believe it or not, judiciously fertilizing your grass actually helps prevent fertilizer run-off.  That’s because grass with a weak root system (as occurs in the typical lawn when you don’t fertilize at all) won’t be able to hold the soil as well — so you get more erosion.  So do fertilize your lawn, just don’t go nuts.

About that whole tree in the lung thing which I posted last week?  Yeah — It’s BS.  How do we know it’s BS?  No obvious roots on the tree and the tree’s needles were green (you don’t get green plants without sunlight). Personally I think this is some kind of odd cry for attention, but I guess it’s possible that the guy swallowed a cutting while he was shearing/pruning trees.  HOWEVER, there are documented cases where seeds will germinate in a persons lung — Usually the person has a compromised immune system.

These are a few of my (least) favorite things…

Spring clean-up came in earnest this weekend at Daisy Hill farm.  Everything will be downhill from here as my least favorite yard chore; cutting back our ornamental grasses, is done for the year.  I know, I know, there are all kinds of shortcuts and tricks for this job including lassoing grasses for the last round-up (see Holly’s March 8 post), duct-taping them, and cutting them down with hedge-trimmers or a chainsaw.  Unfortunately, between our winter snow beating them down and our dogs using them as their own personal jungle playground, standing the grasses up neatly to await a trim just isn’t an option.  So I dive in and do it the old-fashion way; armed with a set of hand-loppers, every piece of  personal protective equipment I can find, and the entire repertoire of swear words my Army sergeant Old Man taught me.  Between hacking, cussing, and hauling it’s a two afternoon job.  On the plus side, it did give me time to ponder my top five list of least favorite yard jobs.  See how it compares with your list…

 

  1. Cutting back ornamental grasses
  2. Picking up black walnuts (this is to Fall what no. 1 is to spring)
  3. Weeding (the only redeeming factor is instant gratification)
  4. Deadheading (yeah, it’s not the hard but you know you’ll have to turn right around and do it again (and again and again…)
  5. Leaf raking (Actually, this wouldn’t be so bad but I went out and bought a chipper-shredder a couple years ago and feel compelled to use it.  Works like a champ – shreds leaves as fast as I can feed them in.  Too bad the bag needs to be emptied approximately every 43 seconds…)

What to do when it’s still raining?

It’s almost May…and it’s still raining. Even for our normally wet spring climate, this has been an unusually soggy year. I’m also blaming the weather on my 3rd or 4th cold so far this year, which has knocked me flat for the last 6 days (which was why I had no Friday puzzle posted). So in between blowing my nose, hacking my lungs out, and generally feeling sorry for myself, I started looking over 10 years’ worth of photos of our home landscape.

You’ve seen bits and pieces of this before in some of my postings. But one of the spots I’m most proud of is the tiny east-facing side yard that originally contained lawn, a lilac, and a border of arborvitae. Within the first few years the lawn came out and plants started going in. In 2004 I’d installed some small rhododendron, a redbud (left foreground), and a whole lot of woodchips:

Since then we removed the lilac (it had been planted too close to the garage and was a powdery mildew magnet), put in an arbor and wisteria (on the right), and added a few more plants (ferns, bleeding hearts, various bulbs and tubers, etc.).  Here it is two (2006) and five (2009) years later:

This year we’ll finish off the area with some flagstone pavers.

One of the main reasons I’m so pleased with this area is that it was inexpensive to redo and it established quickly. We bought the redbud, the wisteria, and the bulbs, but the rest were donations from friends’ gardens, or volunteers that popped up elsewhere in the yard, or plants that someone else wanted removed (like the larger rhody in the far left corner and the dogwood in the right foreground, 2006 photo). The chips were free; the flagstones were a major score from craigslist (free to whomever would pry them up and lug them out).  All the purchased trees and shrubs were barerooted; and root-pruned if needed before planting. Upkeep is minimal except for a bit of pruning and spot watering during the hottest summer months; we’ve lost no plants other than the occasional bulb poaching by squirrels.

It’s just a little bitty sideyard…but I enjoy walking through it every time I’m outside, even in the rain.

Who you gonna call?

As I noted last week, this has been a long winter in Michigan – OK, Jeff, no chortling from the frozen tundra of Minnesota…  Most gardeners in this area have only been able to do their spring yard and garden clean-ups in fits and starts as the weather allows.  We’re finally warming up a bit this week but now strong storms are in the forecast.  One of the things gardeners will want to do is to size up any winter damage that has occurred since they put things to bed last fall.  Although our winter was long, it was otherwise unremarkable with few temperature extremes – low or high – that would likely cause problems.  In fact, aside from some heavy snow in February, the winter of 2010-11 was probably the closest thing we’ve had to a ‘normal’ winter in the 11 years I’ve lived in Michigan.  Nevertheless, we will still be taking numerous extension calls on what we would consider ‘typical’ winter damage to trees and shrubs.

In this neighborhood not too far from my house, deer have declared open season on arborvitae.

One of the biggest issues we face is wildlife damage.  The two biggest sources of problems are small mammals and deer. Small mammals such as mice, rabbits, squirrels and voles cause damage mainly by gnawing on trunks and branches.  Despite their small size, these animals can kill trees by removing bark and underlying tissue around the circumference of a tree trunk, a process referred to as ‘girdling’.  If a large portion of trunk circumference has been girdled, trees are unable to move energy reserves between roots and shoots, and will eventually die.  Deer can cause extensive damage to trees and shrubs due to feeding and also through rubbing their antlers.  Deer feeding is often indicated by a ‘browse line’ based on how high deer can reach.   Rub damage from deer antlers can cause major deformation to trunks and can even kill trees by girdling.  I was in a new subdivision in the East Lansing area this weekend and well over half of the trees on the tree lawns will need to be replaced due to extensive deer rub damage.

At least half of the trees in this entire subdivision will need to be replaced due to deer-rub damage.

Dealing with wildlife damage is a complex issue and varies with local conditions and wildlife pressure.  Fortunately, wildlife experts from several universities (Cornell, Clemson, Nebraska, Utah State) have organized the Internet Center for Wildlife Damage Management. http://icwdm.org/  This site is one of the best resources I have run across for assessing and dealing with wildlife damage issues.  If you’re in a position where you have to deal with wildlife damage or advise clients about damage, this is a useful site to add to your bookmarks.

Invasive plants, politics and science

I’ve had a hectic week (taxes! financial aid!) and haven’t had a chance to think about posting.  Fortunately, yet another colleague just sent me an interesting link that’s worth sharing and discussing.

For those of you who aren’t familiar with how Master Gardener programs work, they are built on volunteers who receive training in garden-related sciences and then contribute a significant number of hours to outreach education.  Many MGs work in plant clinics, and others volunteer in public gardens.  Regardless of where they spend their volunteer hours, they are always representing their sponsoring university and therefore dispense advice and follow practices based on the best available science.

This will help explain why the Master Gardeners who volunteered at the Racine Zoo felt they had to resign their volunteer positions.

(Note that the zoo is losing out on 1300+ hours/year of donated garden upkeep, but the zoo president and CEO is confident that the zoo staff can pick that up.  Wonder if he’ll be out there weeding and watering?)