“Where can I get some good topsoil?” That’s a question I hear frequently at our nursery. And I often look wistfully towards the plains and say, only half-jokingly, “You can get good topsoil about 800 miles east of here.” That’s where I grew up, in Iowa, and where two tomato plants feed a family of six. It’s not that local suppliers are trying to deceive us when they sell Colorado clay as topsoil; it’s just that the glaciers didn’t dump three feet of loam on top of our clay.
Autumn has declared itself on the Front Range, and many gardeners are itching to bring a close to the gardening year by tidying up. But wait! There are some important issues to consider here before bringing out the rakes, blowers, clippers and shears.
Now is a great time to take a long look at your gardens and make notes on successes, disappointments, gaps, and changes that you’d like to make. Assess the ecosystem you have created, and think about how you can make it even more supportive of our precious wildlife, beneficial insects, pollinators and soil life.
A certain amount of garden cleanup is very important for reducing diseases and pests that are difficult to control. If you haven’t already done so, do remove diseased plants from your vegetable garden. You should have been removing and treating diseased foliage from roses or shrubs with fungal diseases like mildew, blackspot or rust before now, but if their disease-carrying foliage is falling now, keep them picked up and dispose of them responsibly.
But don’t be so quick to scalp those perennials and annuals! Many of them provide natural food and shelter sources that wildlife and beneficial insects depend on for winter survival. You may not have noticed, but so many beneficial insects and butterfly larvae spend the winter in the (often hollow) dead stems. If you throw them out, you’ll lose most of the beneficials that would otherwise keep the balance next year. Always keep an eye out for egg cases attached to stalks when you prune or clean up. There’s often an aesthetic side-benefit – many seed-heads look fabulous either crowned with snow or silhouetted against the snow-covered ground.
Some perennials die back to below ground (peonies, false indigo, gas plant, golden banner, balloon flower, desert four o’clock, gayfeather, leadwort/plumbago, etc.) leaving no basal growth and leaving a completely blank space. To make sure you don’t forget where they are and accidentally dig them up or step on them, leave dry stems until the new growth begins to appear in spring.
Unless you have an ‘ornamental’ grass that self-sows aggressively, leave grasses and their seedheads standing. If they are ‘cool-season’ grasses, you’ll want to leave them until about mid-February, then cut them to 3” above the ground so they can begin making unimpeded new growth as soon as the soil thaws. Dormant ‘warm-season’ grasses can remain attractive until warm weather comes and don’t need to be cut down until April.
Leaving dry stalks standing in the winter also helps preserve soil structure. Snow collects between the stalks and provides protection from freezing temperatures by insulation for the crowns of the plants, especially important for marginally hardy plants. Captured snow keeps soil temperature more consistent, protecting from extreme temperature fluctuations, and helps prevent the alternate freezing and thawing that can disrupt mycorrhizal networks (and uproot plants, especially new and small ones).
Leave the leaves! The larvae of many butterflies overwinter in the blanket of autumn leaves, as well as other beneficials. The leaves also provide cover for frogs, toads and spiders. Songbirds eat more than just seeds; they search in the leaf litter for insect eggs and caterpillars. As leaves naturally break down over time, they feed the soil microbes that make nutrients available to plants. Worried about harboring snail and slugs? Before those leaves begin to fall, spread a non-toxic slug bait like Sluggo in areas of concern. You may want to remove leaves and twigs from patios, decks, walkways and lawns, and that’s fine – especially if you can spread them under shrubs or pile them in a corner where they’ll remain undisturbed through the winter. And very large, flat leaves from trees like Catalpa, Basswood (Tilia americana), Norway Maple, Sycamore/London Planetree) should be cleared from beds or they can form a slick solid mat that smothers the crowns of smaller plants.
It’s a common idea that Nature, left to its own devices, comes to some kind of balance. If one organism gets too numerous, something else will increase to reduce that population. In the case of monocultures created by humans, there is an enforced imbalance that has to be propped up with lots of energy and effort. So in the pursuit of sustainability, humans are opening our eyes to the possibility of biomimicry, imitating Nature. We are coming to the realization that biodiversity is far healthier and less energy intensive than monocultures born out of the aggressive hubris to control Nature. “Let Nature take her course.” But we can stack the deck in human favor first.
In this article, Mikl explains why Soil Health matters.
From Peak Soil to Soil Revolution
We are having a real revolution in our relationship with our soils. The turning point is our change in focus from soil fertility to soil health. In the last 60 years of the “Green Revolution” (i.e. the petrochemical boom), soil was viewed as a physical structure and fertility was viewed as a measure of chemicals in the soil — primarily NPK, nitrogen, phosphorus and potassium. The petroleum industry could make these macronutrients from natural gas, which make plants grow but often in poor health. Weak plants attract insect pests and fungal diseases, so more petroleum in the forms of insecticides and fungicides added to the success of the oil industry. But this approach has led to “Peak Soil” where land is losing productivity, crops are losing nutritional value, the soil is eroding at extreme rates, and the health of animals and people has declined.
Trees do a lot for us humans, so we shouldn’t forget to give them some support. When I look at the treeless ten acre lot next to our nursery, or when I see an old photo of the CU campus with bare land around Old Main, I remember why we can’t take trees for granted in Colorado. Trees really have it hard here, but there are things we can do to help them survive and thrive.
The roots are the hidden support system of our giant plants, the trees. They anchor their woody trunks to the ground, store food and bring in water, nutrients and oxygen. In this article I will discuss what is going on down there. In the next issue I will discuss more practical applications of this understanding.
Far less is known about tree roots than about the trunk, branches and leaves. This is understandable since the roots are hidden from our view, and once you dig them up, they are no longer what they were. We are awed by the massive trees swaying over our houses and streets, but usually we give little thought to what is going on under the surface. However, when spring thawing is followed by powerful winds and we see an 80’ spruce toppled over with its roots in the air, which are only 9” deep; that gets us thinking.
What would we do without trees? What structures could we invent and construct that would hang over our houses and offices, providing shade and cooler temperatures? Such a structure would have to hold up under 80 mph winds and heavy wet snows, and would have to retract in the winter to let in light. Trees provide these values and much more, giving off oxygen, providing housing for birds, and protection for understory plants. Thus it is very important to take good care of our trees, and the most fundamental level of that care must be directed to the roots.
It has been suggested that this period of the 21st Century might well be called The Age of Biology, because the biggest challenges will be biological and the biggest breakthroughs will be in the realm of biology.
In this article, we will continue the discussion from the last issue on Biological Agriculture and Gardening, but this time going into specifics of biological thinking, biological discoveries and applications that improve plant and food success with biological solutions.
How can we deal with all the bugs and diseases without using toxic poisons, and how can our gardens really produce without high-powered chemical fertilizers? Many people wanting to garden sustainably are asking these questions. And it is not easy to find the answers, partly because the answers are not simple. I want to admit this up front, but don’t be scared off, because it’s not that hard to garden sustainably once you get the hang of it. However you must know that you can’t just exchange a slam-bam chemical approach for a slam-bam sustainable approach.
The forgotton greenhouse gas and how it relates to growing plants
Nitrogen is one of the most essential nutrients for plants. Nitrogen is required for building amino acids, DNA and RNA, in stimulating growth, supporting health and is a critical ingredient in chlorophyll, the chemical needed for photosynthesis. In our gardens, when nitrogen is lacking, plants are small and yellow, and roots do not perform well. In Colorado, almost all our soils are deficient in nitrogen and organic matter. So we gardeners often add fertilizers and composts to our soils.
It is widely known that nitrogen is essential for plants. It is a major component of amino acids, DNA and chlorophyll. It is necessary for photosynthesis, the alchemical process of turning sunlight, carbon dioxide, minerals and water into oxygen and sugars that is the food that feeds life on earth. In Colorado, most of our soils are deficient in nitrogen.
But too much nitrogen can be a problem, especially high nitrogen chemical fertilizers. Bill McKibben, author of The Art of Balancing Soil Nutrients states, “Although all plant nutrients are critical, none seem to produce such quick and dramatic effect on plant growth as nitrogen does. It is because of this reason that nitrogen has been over-used and abused.” A 20%-30% nitrogen fertilizer can make a spring lawn turn bright green practically overnight, and can make plants in a greenhouse or garden grow and look mature really fast. So what’s the problem?
Flood recovery is not a problem most of us have had to deal with before so we can only try to solve the problems individually and make adjustments in the future.
The main problems seem to be:
1) Soil washed away-erosion
2) Soil dumped on top of plants, trees and existing soil
3) Plants washed away
4) Weed seeds deposited on the soil 5) manure and sewage and unknown contaminants deposited on the land
MULCHING THE GARDEN
Benefits of Mulching:
1) prevents evaporation; holds moisture
2) reduces weeding; makes weeding easier
3) reduces fungal diseases; prevents splashing of spores onto bottom leaves
4) feeds the soil; as mulch decomposes, worms take nutrients into the soil
Applying a mulch around our plants can be one of the most effective ways to improve their health and success, especially during hot and dry conditions like we had in 2012. Mulches have many benefits, but it is important to know how to use them to avoid problems.
Mulch conserves water by reducing evaporation 10%-50%. Usually a 2”-4” deep layer is best, and the material needs to be open enough to admit rain and irrigation and dense enough to resist evaporation. It is a good idea to apply mulch after the soil has been deeply watered or soaked with a good rain. Then the mulch will hold the moisture. Beware of materials like unshredded leaves which can act like shingles, and dry compost or sawdust which are hydrophobic, meaning they are difficult to wet. These problems are worse on a slope where water can run off instead of penetrating.
Normally when we think of fungi relating to plants, what comes to mind is infection and disease: powdery mildew, blackspot, slime flux and canker; Oh, NO!! However there is a growing awareness of the far more extensive benefits that fungi contribute to our world. Decomposing fungi are primary agents in the composting process which to us recyclers is the magic of turning garbage into gold. Not only do our plants love the rich humus and organic matter, but pesticides and herbicides are also broken down. Much of the body of soil itself is made up of fungi, especially loamy, well-aerated soil. And then there are the symbiotic fungi, the ones forming mutually beneficial relationships with plants. These associations of absorbing roots with fungal mycelium are known as mycorrhizae, from “mycor”- fungus and “rhiza”-root. Even though these beneficial relationships were discovered in 1885, it is not widely known today that 95 % of all plants on earth intermingle their roots with mycorrhizal fungi.
Nitrogen is an essential nutrient for all living things. Where does that nitrogen come from? It comes from the atmosphere, which is composed of 78% nitrogen; but that gas is quite inert, meaning it can’t combine with other elements until it is broken into a simpler form. This process takes a lot of energy to “fix” the nitrogen. There are three processes that can fix nitrogen: atmospheric, Haber Process and biological.
Atmospheric fixation occurs when the high temperature of lightning splits the nitrogen gas so it bonds with oxygen and moisture in the air to form nitrates that fall to the earth with rain. This natural fertilization benefits plants. Some people have asked, Is it my imagination that my grass looks greener after a thunderstorm? Maybe not; it could be due to the nitrogen as much as to the water.
Do any of you have dirt under your fingernails? Good. You and all gardeners have direct experience with soil. Those of you who don’t get your hands in the dirt probably will, because soil and soil building is the next frontier. Why do I say that?
Because until recently our understanding of soil and our approach to soil fertility was steeped in ignorance and misunderstanding. We’ve been in the Dark Ages.
Does anybody know the meaning of a new paradigm? It does not mean coming up with a new idea; it means coming up with a new perspective, a new ground from which to begin our thinking. We are entering a new paradigm in relation to the earth.