Wednesday, February 19, 2020

Geotextiles - Dressing the Earth

     Imagine a vibrant garden, teeming with colourful life. Birds flitting to and fro. Fluttering butterflies. Busy, buzzy bees on the hunt for nectar. All shapes and shades of green leaves soaking up the sunlight, swaying in the breeze. Trees casting dancing, dappled shadows. Flowers opening themselves to the glory of it all. Worms, centipedes, beetles and myriad other creepie-crawlies burrowing into and emerging from the soil. And the less seen but equally vital world and work of fungi, bacteria and energy, interacting with and supporting every thing...

     Would you close your eyes for a moment and enter this garden? Smell the moist earth, feel the sun warm your bare skin, merge the energy of your being with this living example of imperfect perfection...
     I mean really, close your eyes for one moment and indulge us both...


     And now, tell me, where would this belong in that glorious scene?

     I suppose since at least the dawn of agriculture "weeds" have plagued us. These paragraphs are a roundup (lower case "r"!) of my personal professional experiences with a certain modern product marketed as "a breathable barrier that provides long lasting weed suppression and moisture retention": Landscape Fabric. Is it necessary or effective?

     Before examining the science or even weighing the pros and cons, I feel my gut calling out its verdict loud and clear, "Covering the earth with woven or thermally bonded polypropylene and polyester, is wrong!" Practically speaking, the majority of the time landscape fabric is unnecessary, and its long term effects are counterproductive and otherwise detrimental.

     Let me take you on a neighbourhood garden stroll, featuring landscape fabric in its myriad glories...

     Notice here the newly installed beds blanketed in a perfect, fresh-off-the-roll black woven plastic, shining in the sun, the uniformity broken only by a few chosen ornamentals, neatly plunked through cutouts into the earth beneath. Everything looks so tidy, so under control. 

     Soon a layer of bark mulch (more on bark mulch later) will likely be applied to make things look natural. Inevitably however, human, animal or elemental action will interrupt this show and once again expose the plastic underbelly of it all.
     On the next avenue we have an older, more established garden. Can you feel something glaring at us from the ground? Disturbed by time, it is a ratty, tatty swath of plastic, now not so shiny, fluttering its frayed edges in the breeze, hinting at the maintenance nightmare of root-infested fabric, feral plants and listless soil. This looks less tidy, almost embarrassing. Like letting a smiling friend know they have spinach stuck in their teeth, I want to say "Psst! Your landscape fabric is showing!"

     Here's a trowel, would you help me weed this patch of dandelions? Please forgive me if a curse word slips out. It's just that as I work in gardens installed before my time, weeding, digging, raking, moving mulches of cellulose and stone, the serenity of the scene is often jarred as my tool encounters something unexpected, something that doesn't quite belong. Not soil, not rock, nor root... it's the unmistakable feel of clashing with that soft, strong plastic barrier... 

     How effective is the geotextile at its principal claim of weed suppression? If you're focused on shallow-rooted annual plants like lamb's quarters and hairy bittercress, you may be in luck... that is until debris collects on top of the barrier, creating a nice substrate for weed seeds to drop in and germinate. As for tap-rooted perennials like tansy, knapweed or even dandelions, I have not found landscape fabric effective for longer than a few months during the growing season, so in the end we are left with the same weeds, plus a buried layer of plastic.

       Our wild grasses seem to delight in tightly entangling root and rhizome into the haven of nooks and crannies that the fabric provides. 

     Supporting a garden includes nurturing connection. Free interactions between many life forms foster rich biodiversity. Although landscape fabric is technically "breathable," it is still a barrier in the garden ecosystem. A barrier to birds looking for worms. A barrier for worms and any other creature that needs to be able to move freely in and out of the soil.

     It's a barrier to the soil system. Debris falling onto the soil surface would normally be broken down into humus and integrated by weather elements and organisms into the soil below, improving its moisture and nutrient holding capacity. With this barrier in place, what falls on top stays on top, and the soil below remains relatively unchanged. In the below photo, the dark and yummy mulch-debris mixture is isolated from the sandy soil beneath, unable to feed the soil food web.   

     Geotextiles are not only a barrier in relation to the garden ecosystem, but one to the gardener herself. In their presence, transplanting, fertilizing and weeding (yes, you will still end up having to weed) can morph from serene garden tasks to nightmares staved off by dread and procrastination. I'm not exaggerating.

     Although careful design and planning helps minimize the need for transplanting, let's face it, there are many plants in our neighbourhood gardens needing to be moved due to light, water, soil or other unforeseen considerations (and that's ok - experiment and learn, people!) Have you ever tried to transplant someone who has been growing amidst landscape fabric for a few years? Below, see the root ball of a shaded out, crowded and deer eaten blueberry shrub needing a new home. A notoriously shallow rooted plant, this blueberry has entangled her roots right into the surrounding geotextile. How do I move her without losing half the root mass? Must I plant a cut-out of root-ridden plastic as well?

     To me, proper, effective weeding means pulling up as much of the offending plant's roots as possible. One way to do this is by plunging your favourite weeding tool into the soil adjacent to said plant, then tilting the tool upwards to pop an area of earth, loosening the bond between root and soil. The fabric blocks your tool, making it near impossible to weed properly. 

     At certain times of the year, it's nice to nourish the soil with compost, manure, or some other trusted natural fertilizer. Again, weather elements, soil creatures and microorganisms will work to integrate these. Plopping these nutritious amendments on top of a layer of plastic just seems counter-intuitive. No graphic needed. 

     And that's not all, folks! I propose there are some deeper motivations behind landscape fabric that speak to our ethics and psyche...   

     Weeding is one of the most groaned-about gardening tasks out there, so here's this product promising to do a large chunk of the work for us. Can we really be faulted for buying into the sales pitch? Isn't progress in the name of efficiency one of humanity's greatest talents? Big agriculture and Roundup help us produce higher yields at lower cost (or something like that, so they say...). Cars help us travel to and fro with speed and ease. Living through screens and apps helps us multitask and stay connected, right? Perhaps, but many of us are now also feeling some of the unpleasant effects of these wondrous advancements. While I've challenged its fundamental claim to weed suppression, landscape fabric has broader effects than simply letting weeds through.

     Remember that when you use geotextiles you are adding plastic to the ecosystem. Whether it's off-gassing a little or a lot, whether it breaks down later rather than sooner, why introduce this ineffective, messy and polluting product into the system at all? Also, because it's a brand new product that we spend our hard earned money on, the purchase of landscape fabric is like another cog driving the all-powerful petroleum machine. At the risk of  betraying my huge emotions, may I say I am personally offended by the attempt to convince us that geotextiles deserve to be part of the landscaping "industry standard."

     As humans we have a need for control. A sense of control helps us feel secure, autonomous and competent, among other things. Gardeners are no exception, and although the desire for control is obvious in a landscape like this,

it is also present here,

     I wonder whether, in the face of something as disobedient as weeds, something as dire and eternal as the cycle of pulling weeds only to have them quickly regrow (actually I don't find this cycle all that dire and have even created and shared a workshop called We Love Weeds!), we use landscape fabric to allay a feeling of hopelessness. We get a dose of retail therapy, and perhaps a sense of accomplishment as we unwrap and unroll the fabric; everything just looks so neat and under control and phew! - no weeds!
     Until (cue theme tune from the movie Jaws)...

wild grass poking through relatively fresh, intact geotextile
    Despite the trend of framing the garden as an extension of the house, an "outdoor room," the truth is the garden is outside. The garden is full of billions of living beings and living relationships, from top to bottom, from tiny to toweringly tall. Sometimes I wonder whether the zeal of house construction and renovation is allowed to percolate into the garden soil a bit too much. Just because the house frame must be covered in Tyvek does not mean the earth around it ought to be as well. 

     Resources like manure, compost, topsoil, mulches and seed banks can make a gardener feel rich. Being resourceful can make a gardner feel not only rich, but powerful. Driving to the store to buy a new package of plastic-wrapped plastic would not make me feel particularly resourceful or powerful, but gaining an understanding of the soil, the particular weeds growing and what they communicate, and using ecologically supportive methods and local, inexpensive or free materials, might.

     So what can we do to lighten the weeding load?

     First of all, lighten the emotional load. Remember that beauty is a subjective thing and consider whether you truly hate those dandelions or you have simply been programmed to. To quote Ambra Edwards from her book Head Gardeners, I personally prefer my gardens "...not too tidy, and richly atmospheric."

     Learn about your weeds. Learn about their role in the ecosystem (are they benefitting others?); which environmental factors (soil conditions, human disturbance, etc.) invite them; what type of root they have, their life cycle, how they spread; and how they may benefit you as food, medicine, fibre, dye, or even simple children's bouquets. Recognizing these benefits doesn't mean the plants have to stay, but it may help us get a bigger picture and an appreciation of the ecosystem as a whole.

     Help your chosen plants out-compete the "weeds" by nourishing the soil. Many weeds prefer nutritionally poor, disturbed sites.

     Before planting new areas, make careful plans that consider soil, weather conditions, and appropriate plant selection, and then prepare, prepare, prepare the site before planting. And then prepare the site! This may include weeding, cultivation, sheet mulching and/or amending.

     Nature does not leave bare soil exposed for long, take a tip from her and mulch. In the interest of resourcefulness I will consider repurposing materials already available on site, however my preference for mulch is leaves or ramial (branches up to 7cm diameter) wood chips. Please note the difference between wood chips and bark mulch: from Heide Hermary's Working With Nature, "Bark is a protective structure where plants accumulate toxins as a preventative defense mechanism against invading insects and microbes... bark mulch inhibits soil biodiversity, as well as adding very little in the way of nutrients." Ramial wood chips contain a variety of branch sizes as well as leaves, and in addition to performing the typical mulch functions of weed suppression, moisture retention and temperature regulation, they quickly break down and increase the humus content of the soil.

     With their inks, glues and tape residues, not to mention fungicide sprays for some produce, cardboard boxes are not completely natural. However with a bit of selectivity you can procure a weed barrier that has many advantages over geotextiles: when layered properly, cardboard can effectively smother weeds; earthworms are inexplicably attracted to it; it's recycled, repurposed and free; it's relatively natural and biodegradable; and my favourite part, it will not create a long lasting barrier to the ecosystem (or the gardener), instead rapidly breaking down with adequate moisture, allowing natural garden interactions to reestablish themselves.

    I have also experimented with smothering patches of weedy ground with black plastic lumber wrapping from lumberyards. This is a short term (1-2 years) application, not one buried under mulches and left to become a permanent fixture in the garden. Yes, it is plastic (and unfortunately it's of a quality that tends to degrade quickly and can leave shredded bits in the soil if left too long) but at least it's free and repurposed plastic. Lumber wrapping is far from ideal, but I'd give a "waste" item a second (and third) life before it goes to the landfill rather than buy a new product, any day.

     While there are many respectable ways to ease the chore, I encourage you to get comfortable with weeding. It's part of gardening. It can be a quiet time to reflect or let the busy mind empty; a time to personally greet and observe each plant and nook in the garden, a time to listen to the birds and bask in the outdoors; a time to practice more of the postural mainstay of our ancestors: squatting; a time to harvest some minerally and medicinally dense greens; a time to marvel at the irrepressible vitality of life on this earth.




some people love dandelions!

my preferred "geotextile"