Nurturing Garden Soil

It is a clear blue-sky day in early spring when the garden’s life is waking from a long winter’s sleep.  The vegetable beds are bare, their dark soil soaking up rain one day, warmed by sunlight the next.   At their surface or just below, signs of the garden’s awakening abound.

Scarab beetles lumber sleepily over clods of damp clayey soil.  Earthworms tunnel just below the soil surface while a stubby banded woolly caterpillar crawls lazily above them.  All around, birds argue about nesting territory.

A native solitary bee forages for nectar on a dandelion flower.

A native solitary bee forages for nectar on a dandelion flower.

A bumblebee queen stirs in her underground winter’s nest at the edge of the garden where she spent the long winter alone, the sole survivor of a teeming summer colony.  In a week or so she will be seen flying over the garden in search of early nectar.  She will be joined by adult solitary bees, awakened from a long winter’s sleep in cramped cells stacked end-to-end in an old fence post, searching first for mates, then for dandelions in bloom.

And the life the gardener cannot see, but knows must be there, is waking.  Single-celled and multicellular, these invisible soil-builders, bacteria and fungi, begin their work of breaking down organic matter into nutrients that the garden’s plants must have to succeed.  As the soil warms, their populations expand.

Into this community of life, this ecosystem called the garden, comes the gentle gardener.  She treads lightly on paths made for walking, circling beds raised above the paths by years of topdressing with compost.  She carries only tools that fit her hand, extensions of her hand.  No plow, no tiller, has ever been in this garden.

She sows seeds and transplants seedlings with the least possible disturbance of the life around them, for it is this life that will feed the growing plants, enable them to mature, to bear leaves and fruit.  Weeds, if they are troublesome, are pulled by hand.  She has a helper, a partner, and between them the garden thrives.

The Minimum-till Garden

I started gardening several decades ago, at a time when double-digging of garden beds was the prevailing paradigm.  Now I know better, having arrived at a view of the gardener as caretaker of the life in the garden.  In this view, deep tilling of the soil is anathema.

A cover crop of oats in April.

A cover crop of oats in April.

Marjorie and I have had some interesting discussions on the question of when, if ever, the soil should be invaded by a spade, considering the resulting disruption of soil life.  (We never talk about using a tiller–we don’t own one.)  For example, is cover-cropping with winter rye, which is still alive at the end of winter, worth the disruption of soil life and delay in planting caused by digging in a green cover crop?  Perhaps not.  There are other annual cover crops, such as oats and annual ryegrass, winter-killed crops that can be used as a mulch, decomposing rapidly on the soil surface after sowing seed or transplanting seedlings.

A cover crop of annual ryegrass in late autumn, before a killing freeze.

A cover crop of annual ryegrass in late autumn, before a killing freeze.

And perhaps the same goal, increasing the organic matter content of the soil, can be accomplished by topdressing with composted manure.  This was my thinking when I realized how many earthworms I kill when I turn over a cover crop of winter rye.  (No, they don’t grow back the missing half.  They die.)  Not to mention the disruption of microbial life in the soil caused by digging.

So, when I plant peas in early spring, I do it as non-invasively as possible, making furrows in the soil and covering the seeds by hand.  I may relocate a worm or two, but I won’t bisect any.  Life below the inch-deep furrows will go on undisturbed.  When I transplant tomato seedlings in early June, I will dig the planting holes by hand, throwing a handful of compost in the bottom of each hole as penance for the disturbance.

In my mind, no good can come from tilling or digging established garden beds.  Each tilling or digging disturbs the natural growing environment of plant roots, breaks up fungal hyphae, kills worms and arthropods, destroys soil structure, and eventually reduces soil aeration.  Tillage disrupts the complex cycling of nutrients through the soil food web.  It brings dormant weed seeds to the surface where they will sprout.

Minimal-till gardens have fewer insect herbivores and plant diseases, likely due to the more balanced community of life in an undisturbed soil environment.

Nourishing life in the garden, treading lightly, providing habitat for pollinators and other wildlife, this is the gardener’s work.  Leave the deep tilling to the earthworms.

Organic Mulches

Every spring, as soon as the soil has thawed and drained, we pick a sunny afternoon to plant peas and onions.  Typically this first activity in the vegetable garden captures the attention of several crows, who watch from a nearby birch.

I feel the sun’s warmth on my back and the soil’s warmth in my fingers as I dig two-inch-deep furrows down the length of a garden bed.  Into each furrow I scatter pea seeds, plump with water just imbibed, then cover them with the warm soil, gently patting it down with the flat of my hand.  All the while, the crows watch…

I push twiggy birch branches into the soil between the rows, forming a four-foot scaffold for future pea tendrils and an immediate barrier to scheming seed scavengers.  Defeated, the crows fly off as I soak the bed with a gentle shower.

Finally, I spread over the bed a thin blanket of shredded leaves, one handful at a time pulled from a bag stored in the basement since fall when we spread them in an open space on the drainfield and shredded them with a lawn mower.  Dry leaf dust drifts downwind as I settle the leaf mulch into place with a final watering.

We also use shredded leaves to mulch the onion transplants, just enough to cover the soil, hold in the moisture, keep the root run cool, and perhaps make it a little harder for weed seeds to get started.  Later, after the plants are established and growing, we lay down a deeper mulch.

Nannyberries, next year's garden mulch, will be covered with a tarp through the winter.

Nannyberries, next year’s garden mulch, will be covered with a tarp through the winter.

We also do a lot of mulching with composted goat manure, “nannyberries,” applying it liberally around the highbush blueberries, raspberries, and our grape vine as these small fruit crops begin growth in early spring.  Nannyberries have replaced straw as the mulch of choice for these crops; we learned from a small-fruits expert that mulching with straw can increase chances of root rot disease in raspberries.

Nannyberries are too coarse for use where vegetable seeds will be sown and often contain too much nitrogen to place in direct contact with tender transplants.  We spread nannyberries over the soil of most vegetable beds in the fall, relying on shredded leaves as mulch for these beds after planting.

Finished compost ready for spreading on the garden soil.

Finished compost ready for spreading on the garden soil.

Finished garden compost is another excellent mulch.  A mixture of vegetable scraps from the kitchen, spent plants from the garden, shredded leaves, seaweed (when we can get it), and nannyberries, our compost pile decomposes through the summer and, by October, yields a modest amount of rich, crumbly mulch.   We screen it first, eliminating tough stems and other course materials that need more time to break down, then spread it where it is needed most, often on the strawberry beds.

And we mulch with worm castings.  Over the course of a year, the worm bin occupants transform pounds of banana peels, coffee grounds, and other kitchen vegetable waste into buckets of nutrient-rich castings.  Blueberries and raspberries are the usual beneficiaries.

Organic mulches are the only fertilizer for our trees, shrubs, and perennials.  In the vegetable garden, organic mulches supply sufficient quantities of nitrogen and other essential nutrients for sustained vegetable and fruit production, year after year.

Organic mulches should be in the final stages of decomposition.  Wood chips, shredded wood, and sawdust are excellent mulches for garden walkways but should never be used where plants are grown.  The wood in these products consists of large molecules, mostly lignin and cellulose, which must be decomposed by legions of soil bacteria into smaller molecules.  The hard-working microbes utilize the bulk of the soil’s nitrogen as they work, leaving the garden plants nitrogen-starved.

Author’s note: Learn more about nurturing healthy soil and many other aspects of gardening in tune with nature in THE NEW ENGLAND GARDENER’S YEAR by Reeser Manley and Marjorie Peronto (2013, Cadent Publishing), available at your local bookstore and online.

This entry was posted in ecologicaly functional garden by Reeser Manley. Bookmark the permalink.

About Reeser Manley

I was born in Laramie Wyoming but moved to the southeast at an early age. I was educated through my B.S. in Biology in the Columbus, Georgia area, then crossed the Chattahoochee River to earn my M.S. in Botany at Auburn University. For the next ten years, I worked as Horticultural Manager for the George W. Park Seed Co. in Greenwood, S.C. At 40 years of age, I decided to return to graduate school and in 1994, I earned a Ph.D. in Horticultural Science from Washington State University, Pullman, Washington. Fast forward through 10 years at university (7 at UMaine, Orono) and you find me teaching high school science in Eastport, Maine, the edge of the world, and writing a weekly garden column for the Bangor Daily News. My new book, The New England Gardener's Year, a Month-by-Month Guide for Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, Connecticut, and Upstate New York”, will be published later this year by Cadent Publishing. You can learn more about the book by visiting its Facebook page: http://www.facebook.com/pages/The-New-England-Gardeners-Year/187285218055676.)