Cheyenne Garden Gossip

Gardening on the high plains of southeastern Wyoming


Soil microbes better than rototilling

2017-05Lowenfels-Endomycorrhizal fungi

Endomycorrhizal fungi spores are ready to grow into plant roots, carrying nutrients and moisture. Photo courtesy of Jeff Lowenfels.

Published May 7, 2017, in the Wyoming Tribune Eagle, “Soil microbes, no rototilling key to next generation of gardening”

By Barb Gorges

Twice in the space of a month this spring I heard rototilling renounced for the sake of keeping soil microbes healthy.

One speaker was Jeff Lowenfels, garden columnist and author from Alaska who spoke at the Cheyenne Botanic Gardens/Laramie County Master Gardener spring lecture series. The other was Ron Godin, recently retired extension agronomist in western Colorado, speaking at the Wild West Gardening Conference in Cheyenne.

There are a billion microbes in a teaspoon of healthy soil. The interactions of the whole community of microbes is a giant web of who eats whom and who feeds whom.

Basically, decaying plant material feeds microbes and in turn, microbe “excrement” feeds plant roots.

Microbes include nematodes, bacteria, fungi and protozoa. There are some bad actors, but in general, everything balances and plants grow. For example, prairies and forests have self-sustaining soil microbial communities—no synthetic, chemical fertilizers or pesticides are required.

But when European farmers landed in the New World, they opened things up with the plow and have continued to plow ever since. Regular plowing (or hoeing or rototilling) disrupts the soil microbes. They can’t do their jobs. Farmers repaired damage somewhat with applications of manure and compost. But then came the 20th century’s inventive use of nerve gas left over from World War I as insecticide, and leftover nitrogen-based bomb-making materials from World War II became the perfect fertilizer.

Except that it wasn’t healthy for the microbes.

2017-05 Lowenfels-Ectomycorryhizal fungi

Ectomycorrhizal fungi grow close to the surface of roots and grow webs around them carrying water and nutrients. Photo courtesy of Jeff Lowenfels.

Synthetic fertilizers starve the microbes in a way and pesticides kill off beneficial organisms, causing the need for a never-ending cycle of synthetic fertilizer and pesticide application. This was great if you owned stock in the large chemical companies, but bad when you understand the side effects including health issues animals and humans—especially farmers, because the chemicals get into drinking water and food.

 

Lowenfels happily dispensed advice on garden chemicals for years until someone sent him two electron microscope photos, one of a fungus that had trapped a root-eating nematode, and the other of a nematode happily chomping a tomato root unimpeded.

In the first photo, the plant was secreting a substance that attracted the fungus, which in turn attacked the nematode. In the second photo, the fungus was missing due to the use of synthetic fertilizers and pesticides.

After his conversion, Lowenfels wrote three books. He said the essential one is “Teaming with Microbes, The Organic Gardener’s Guide to the Soil Food Web,” coauthored with Wayne Lewis. You’ll notice the play on words in the title–healthy soil is teeming with microbes, and you’ll be teaming with them.

Put away the rototiller

First, put away your rototiller. It’s still handy if you are turning your lawn into a pollinator garden, but otherwise, annual rototilling is detrimental to the soil microbe community. Godin said this advice translates to farming as well.

It will take time to undo the cultural tradition of breaking soil down into a fine, clump-less and smooth expanse of dirt. But there are two reasons for disturbing the soil as little as possible, even in a vegetable garden.

First, every time you dig into soil, you bring up weed seeds, most of which require light to germinate. You just made more work for yourself. Cut weeds off at the soil surface rather than digging them.

Second, microbes feeding your plants and fending off bad stuff can’t function if you break them up. Keeping them intact means less work for you, less fertilizer spreading, less watering since healthy soil holds water better. Pesticides are a last resort for serious problems. Re-inoculate your soil with microbes soon after.

In windy Cheyenne, there’s also a third benefit to not tilling your soil into fine dust: microbes “glue” things together and the resulting clumpy soil doesn’t blow away.

2017-05Lowenfels-Glomalin--green stain--coating with spores

In this electron microscopic view, Glomalin, stained green and coated with spores, is produced by a group of common soil fungi. It coats soil particles like super glue, sticking them together in clumps. Photo courtesy of Jeff Lowenfels.

To plant seeds or transplants, make an opening just large enough. The roots will find their way without the soil being “fluffed.” Healthy soil has lots of air spaces already. Then mulch.

 

Godin’s rule is 100 percent cover, 100 percent of the time. Cover for large gardens or farms could be annual cover crops later mowed to form mulch. In small gardens use leaves, grass clippings and compost.

Replace chemical fertilizers

In the years chemical fertilizers have been around, studies show fruits and vegetables have dropped in nutritional value. It’s due to the missing micronutrients soil microbes used to pull from decomposing plant material and mineral soils. Synthetic fertilizer is incomplete.

Traditional organic gardening recommends digging compost into the soil, but  Lowenfels says digging breaks up the soil community. Better to side-dress plants, leaving the compost (or mulch) on the soil surface where microbes will get at it and break it down. It works on the prairie and in the forest—there’s no 100-year-old pile of dead grass, leaves or pine needles.

Lowenfels said there are three different groups of plants in your yard. Perennial flowers, shrubs and trees want their nitrogen in the form provided by fungally dominated soils. The compost that promotes this is the brown stuff (mixed with a little green): dry leaves, bark, wood chips, twigs, branches—like the forest floor.

Annuals, including vegetables, prefer their nitrogen produced by bacterially dominated soil. This is green stuff (with a little brown), grass clippings, freshly picked weeds (without seeds) and fruit and vegetable kitchen scraps.

The prairie, like your lawn, falls in between. It appreciates finely shredded brown fall leaves and thin layers of green grass clippings.

Brew compost tea

Compost tea, compost soaked in water, is another way to inoculate your garden with microbes and feed them too. If compost and compost tea smell ugly, that’s anaerobic activity. You need aerobic activity—more air.

Lowenfels gives directions for making a bucket into “a simple actively aerated compost tea brewer using aquarium pumps and air stones.” Fertilizing your plants, and yes, your houseplants too, is as easy as watering them.

While chemical companies made their fortunes keeping our soils addicted to their products, new companies are offering to aid us in bringing our soils back to health. They are building better compost tea brewers. Labs can estimate your microbe population. Our local independent garden centers will sell you mycorrhizal fungi in powdered form you mix with water.

This new era of catering to microbes has gone mainstream. Lowenfels reported that at the 2016 Garden Writers of America conference, none of the tradeshow vendors was pushing synthetic fertilizers or pesticides.

For the last 35 years, my husband, Mark, and I have cared for our lawn and garden without a rototiller or synthetic fertilizers and pesticides. We mulch the garden and use natural lawn fertilizers. I look forward to adapting Lowenfels’ ideas to step it up.

[If you are also adapting to the new era in gardening, let me know how it is going. Contact me at bgorges2 at gmail.com.]

More information:

Besides “Teaming with Microbes,” his first book, Lowenfels has also authored:

–“Teaming with Nutrients, The Organic Gardener’s Guide to Optimizing Plant Nutrition”

–“Teaming with Fungi, The Organic Grower’s Guide to Mycorrhizae.”

 

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Soil Testing: Interpreting the Results

soil test results

Colorado State University soil testing results

Published May 25, 2013, in the Wyoming Tribune Eagle, “Did Barb’s soil pass the test? The results are in on a soil sample the columnist had analyzed by CSU.”

By Barb Gorges

The other day, my soil test results came in by email from Colorado State University’s Soil, Water and Plant Testing Laboratory.

As I opened the attachment, I felt a little trepidation, not unlike anticipating getting my cholesterol numbers from the health fair. Both tests document my progress in healthy living–or making healthy soil–within the limits of genetics–or bedrock.

pH balance

My front lawn’s pH was high at 7.4, but my vegetable garden was 7.2, within the preferred range of 6 to 7.2.

So I have alkaline soil—typical for this region. Most plants will still grow fine, except for acid-loving species. Because acidification treatments cost money and are not long lasting, we Westerners should instead take advantage of alkaline-loving plants.

Soil texture

Local gardeners often talk about Cheyenne’s clay soil texture so I was surprised my vegetable garden tested as sandy loam and the front yard as sandy clay loam.

“Loam” describes the perfect combination of sand, silt and clay particles for horticulture and agriculture: just enough sand for good drainage, just enough silt and clay to hold water and nutrients.

The modifier “sandy” means water will drain more quickly. This explains why I needed to water the veggies every morning last summer. With “clay” in the lawn’s soil texture description, it means it holds water well, but percolation is slower. That means when you water, apply it slowly.

Organic material

In my vegetable garden, organic material tested at 3.9 percent. This isn’t bad for an area that was first cultivated a year ago and amended with leaf compost.

The recommendation is to increase this category to 5 percent over the next two or three years by adding 2 to 3 inches of plant-based compost or 1 inch of animal-based compost in spring or fall, incorporating it into the top 6 to 8 inches of soil.

The front lawn, which I would love to convert to flower garden, came in at 4 percent. Though I can improve that, less may actually be better for native, drought-resistant plants I would choose.

Why organic matter?

Without it, soil would be nothing but weathered rock. Yes, you get many nutrients from minerals, but organic material feeds the soil microorganisms which feed your plants. The process also improves soil structure, which improves water permeability and absorption (think lower water bill). There can be as many as a billion microorganisms in a quarter teaspoon of topsoil. They are the real engines of plant growth.

Remember where organic material comes from? Plant and animal matter. It’s a cycle as old as life.

Fertilizer history

Sometime during the 20th century, chemists determined plants could grow with nutrients from chemically processed mineral salts.

Today, it is common knowledge that highly processed fertilizers don’t feed microorganisms the way organic (plant and animal-based) fertilizers do. And sometimes they leave behind a buildup of salty residue that is hard on plants.

Unfortunately, the big fertilizer companies have become so influential that it is not always easy to pursue what we now call organic gardening and farming—back to the future, as I think of it, since organic growers use Grandpa’s pre-chemical farming knowledge augmented by new discoveries about organic materials.

Fertilizers

The vegetation of natural landscapes is the result of perfect nutrient cycling. However, gardens and lawns are more intensively grown and the natural nutrient cycle often needs our help.

We have a tendency to over-fertilize, which pollutes groundwater and surface water with the excess, and wastes our money.

As I read labels on various bags and bottles, I realized perhaps the reason we over-fertilize because many of us have trouble understanding the labels. And so we calculate fertilizer amounts as best we can–and then throwing in a little extra for good luck.

Actually, we should err on the side of less. It’s surprising we don’t kill everything growing in our yards with our generosity.

I confess to being stingy. In the days I only grew perennial flowers, I never fertilized with anything other than decomposing leaf mulch. Mark uses Revive, an organic fertilizer, on our lawn.

But now, thanks to my soil test, I have actual numbers to strike a balance between stingy and overgenerous.

 N is for Nitrate (Nitrogen)

Both my lawn and vegetable garden were low in nitrogen. Nitrogen is one of the three major nutrients, the one responsible for stems and leaves. But if you put too much on in one year, it interferes with producing flower and fruit buds and the excess disappears before the next growing season.

 P is for Phosphorus

Surprisingly, in my vegetable garden, this came in high. But the lawn needs some. Phosphorus gives plants strong roots, resistance to disease and good fruit development.

 K is for Potassium

Again, the vegetable garden came in high, and the anaylsis recommends adding a bit to the front yard–if I convert it to flowers. Plants need potassium for successful blooming—for flowers and fruiting vegetables like tomatoes.

Other results

Electrical conductivity: In both areas of my yard, electrical conductivity was low, a good thing, meaning no salty, plant-killing soil.

Lime: Rated medium, OK for growing plants.

Why a local store sells lime is beyond me. With very, very few exceptions, adding lime to Wyoming soils will only increase alkalinity, perhaps to toxic levels.

Micronutrients: Zinc, iron, manganese, copper and boron are all necessary for healthy plants but, as in my yard, they are seldom deficient here.

Recommended fertilizers

All processed fertilizers, whether they are chemically manufactured or lightly processed organic—meaning carbon-based, not necessarily organic as in growing method—have their N-P-K percentages listed on the label. The plants don’t care where these nutrients come from. But organic-based fertilizers release nutrients more slowly, provide some of that all important organic material, and they are safer around children and pets.

Needing just nitrogen for the vegetable garden, the soil test results recommended urea or ammonium sulfate, or one of three more organic choices: blood meal, corn gluten meal or alfalfa meal pellets—for that final item, think rabbit food.

The lawn needs three times as much nitrogen and phosphorus, by weight, as it does potassium. None of the “balanced” fertilizers containing all three really came close to these proportions, so I also looked at the individual recommendations for phosphorus and potassium. For phosphorus it was either bone meal (organic) or triplesuperphosphate (chemical). For potassium, potassium chloride or composted manure.

Shopping

Chemical fertilizers are available at garden centers all around town. Some of the organics are common as well, such as bone meal. Grant Farms has a good selection of fertilizers from organic materials.

For corn gluten, cottonseed meal and alfalfa pellets, check A & C Feed.

Calculations

My soil test result sheets explained how to figure out how much of the unconventional fertilizers I needed—after all, alfalfa pellets don’t come with nitrogen-phosphorus-potassium analysis.

Note: Here’s the formula cited by CSU’s lab, using nitrogen as the example: “…take the amount of N needed (my soil test results recommended 0.3 lbs. per 100 square feet) and divide by the % N in the fertilizer. For example, if your fertilizer contains 30% N, take 0.30 lbs (N needed) divided by 0.30 (N in the fertilizer) to get 1 lb of the 30% N fertilizer that is needed to apply per 100 sq. ft. For rates per 1000 sq. ft. multiply the quantities by 10.”

Essentially, for my 100 square foot garden I only need a pound of 30 percent nitrogen fertilizer—15 pounds of alfalfa pellets that will provide organic material as well. Perhaps my leaf compost can substitute for some of that.

Spreading

I think I can spread fertilizer over my tiny garden evenly by hand before digging it in, but the lawn, if I don’t convert it to garden this year, needs one of those spreaders for which you can adjust the rate.

On the other hand, a mature lawn doesn’t need fertilizing until late summer, so I can put that off for now. But when we mow we should start leaving our clippings on the lawn to decompose. They will not become thatch—other issues cause thatch build-up.

 The next test

In four or five years we can do another soil test and see how we’ve progressed toward our goals.

Caveats

Always read fertilizer directions thoroughly—and follow them for best results, and for your own health.

Think twice about using manure. If it’s fresh, it may burn plants. Avoid pig, dog or cat manure because their diseases can last years in soil and travel via vegetables to humans. And if manure from herbivores isn’t composted at high enough temperatures, it may carry viable weed seeds.

Be aware of how much salt comes with the fertilizer of your choice.

Organic materials from your own yard—unless sprayed with pesticides or diseased—are not yard waste. They’re treasure.

There are many fertilizer sources I haven’t discussed that are worth looking into, such as fish emulsion and cover crops that become green manure, among others.

 Resources

If you have questions on how to improve soil, it may be worth consulting an expert, especially at one of the local agencies that offer free advice.

You can also find out from them how to get your soil tested.

Also, check their websites or offices for bulletins with garden advice tailored to our area.

 Free Local Gardening Advice

**Laramie County Conservation District, 11221 U.S. Hwy 30, 772-2600, http://www.lccdnet.org.

**Laramie County Cooperative Extension, 310 W. 19th, 1st Floor, 633-4383, http://www.wyomingextension.org/publications/.

**Cheyenne Botanic Gardens, 710 S. Lions Park Dr., 637-6458, http://botanic.org/ (gardening advice specifically for Cheyenne).


Soil Testing: Preparing the Samples

soil test application

Colorado State University’s soil testing application and instructions

Published April 21, 2013, in the Wyoming Tribune Eagle, “Get the dirt on soil: Maximize your lawn and garden success by finding the exact concoction of nutrients they need—with a little help from CSU.”

By Barb Gorges

You might be used to putting fertilizer on your lawn and in your garden.

But do you really know what nutrients they need and how much?

Yes, the major nutrients, nitrogen, phosphorus and potassium, the three big numbers you see on fertilizer bags, are important.

But the balance may not be right for your soil. You could be adding too much of a good thing.

Besides the fact that you might be wasting your money, consider the bigger picture.

If the concoction of fertilizer has more nitrogen than your lawn needs, the excess washes into the ground water, polluting someone’s future drinking water.

Excess phosphorus washes into local streams and ponds causing algal blooms, possibly suffocating other aquatic life.

Unlike your plants’ other needs of water and light, it’s not always obvious when your plants need more or less food. In extreme cases, you’ll see yellowed leaves or stunted growth in malnourished plants.

And too much nitrogen, for example, could spur the plant into producing an overabundance of leaves but no blossoms—no flowers, no fruit.

To get ahead of these issues before the growing season, you may want to test your soil.

Luckily, sampling is fairly easy. Unlike my Soils 101 class back in college, I don’t have to dig a 5-foot pit to find out what my soil is made of. This time, I only had to send in samples from the top 6 inches of the areas I wanted the lab to examine.

What a soil test tells you

Soil texture will tell you something about its fertility.

Is your soil sandy? If so, water (and dissolved nutrients) will percolate through it quickly.

Is your soil clayey like so much of Cheyenne’s? Water moves through it slowly. The lab can recommend how much water and what rate you should apply it to your garden or lawn.

Testing for electrical conductivity sounds odd, but that’s the way to find out how salty your soil is, which can affect the availability of nutrients to plants. Some soils are naturally salty, but often here they become that way because too much fertilizer has been added over time, or the irrigation water is salty–comparatively speaking.

Knowing a soil’s pH will help you understand how easily some nutrients can be taken up by plants. It will also tell you what plants may not grow well.

The Cheyenne area typically has alkaline soil. That is why soil amendment advice for the acidic soils of the eastern U.S., such as adding lime or wood ash, can be counterproductive here. Acid-loving plants, such as blueberries and rhododendron, will not grow here unless you plant them in a container in which you can acidify the soil.

The percentage of organic matter in your soil should match your garden plans. It is possible to add too much compost or manure for the plants you want to grow.

Get a soil-testing kit

Home testing kits sold in stores are not usually designed for our alkaline soils and also, the information will not be precise enough.

Colorado State University’s Soil, Water and Plant Testing Laboratory in Fort Collins is one of the few remaining labs of this kind at land grant universities. Being in our neighborhood, the folks at the CSU lab will understand our soils better than those farther away.

The standard test costs $31. See the accompanying information on how to get a sampling bottle, directions and submission form.

Follow the directions

Whatever lab you use, follow their directions.

CSU’s indicated that to get a balanced sample, I needed to collect the same amount of soil at each level—I needed to dig a perfect cylinder 6 inches deep. And dig one of these perfect cylinders 5 to 15 times in random places in my garden or lawn.

How do you get a cylinder of soil? The right tool for the job is a soil probe.

I went out to the Laramie County Conservation District office and asked Jim Cochran, district manager, if he had one I could borrow. He did. And you can borrow one, too.

A soil probe is a nifty little tool, a stainless steel pipe about an inch in diameter and three or four feet long, with a crossbar handle. You punch it into the ground 6 inches and pull out your sample, which you then dump out the side vent.

Well, almost. In my vegetable garden I had trouble keeping the soil in the tube until I was ready to dump it in my plastic dishpan. Maybe the soil needed to be just a little moister. I also tried twirling the probe to keep in the dirt.

Twirling didn’t get me more than an inch into one spot in my front lawn, even after making sure I was between blades of grass. I hit solid clay near the house—probably left by the builders 50 years ago. I had to get husband Mark to help. And then, I needed a sharp tool to dig the clay out of the probe.

I decided to sample both the vegetable garden and the front lawn areas. I took enough sub-samples of the lawn to make two cups’ worth and then mixed them together in a dishpan, doing the same in a separate dishpan for the vegetable garden sub-samples.

The directions said to break up clods and remove organic matter. I picked out as many roots as I could, and a few worms. I spread the dirt (excuse me, soil) out in the bottom of the pans and by the next day both samples were dry enough. Don’t use the oven—it will stink up the house and distort your nitrogen readings.

An important part of the testing is filling out the paperwork. The lab wants to know what’s been growing in the tested area, what fertilizers have been used and how much it is irrigated, so they can understand any anomalies they find. They also want to know what you plan to grow so they can make recommendations.

There is no good or bad soil. It just depends on what you want to grow and whether your soil currently is capable.

In a way, my perennial flower bed performs its own suitability exam. I plant a new type of perennial and if it doesn’t thrive–which could be due to incompatible amounts of light and water as well as incompatible soil–I know I should remember that experience and try something else the next year.

But now that I’m growing vegetables, which can deplete the soil, and we have a lawn that isn’t quite thick enough to shade out the dandelions, I’m curious to see what a soil test can tell me.

In next month’s column we’ll look at the soil testing results and find out what they mean.

 Where to get a CSU soil sampling bottle, directions and submission form

**Laramie County Conservation District, 11221 U.S. Hwy 30 (nearly 10 miles east of downtown, west of I-80 Exit 370), 772-2600.

**Laramie County Cooperative Extension, 310 W. 19th, 1st Floor, 633-4383.

**www.soiltestinglab.colostate.edu (put soil sample in Zip-loc-type bag and print and fill out the submission form)

**Soil, Water and Plant Testing Laboratory, Ft. Collins, Colo., 970-491-5061.