Sustainable-enough potting mix

To test the usefulness of my homemade potting mix and compare it to commercial products, I’ve been working this winter on propagating African violets. I made the potting mix to avoid using peat, which I learned is not a renewable resource. The mix is half compost from my yard and half coir, or coconut fiber.

    Like so many of my gardening methods, it’s “sustainable-enough” rather than ideal. That’s because the coir comes from Hawaii, accruing significant carbon cost on its 6,000-mile journey to Massachusetts. On the plus side, coir is a byproduct that I can put to good use, and compared to depleting peat bogs, which are major carbon sinks, I think non-local coir is the better alternative.

    I’ve had luck with African violets as houseplants probably because they tolerate neglect. My collection has been living for years on pebble trays next to an east-facing window. Their winter blooms are a morale booster. I’ll betray my amateurism by admitting that I haven’t kept track of the names of the varieties I’m growing. My favorite has blue flowers and purplish foliage. 

The pink ones are nice too.

    I wanted to try multiplying my collection by rooting single leaves. I cut off a few with stems about two inches long and stuck them into moistened potting mix in November. I enclosed them in plastic bags for a humid environment and put them under a grow light in the kitchen. Nothing happened for many months.

    Meanwhile, I discovered an excellent youtube video demonstrating how to propagate African violets from leaves, made by an anonymous benefactor who obviously knows what she’s doing. After watching her demonstration, I was able to start a new batch with several improvements in my technique.

    First, since the new sprouts grow from the cut end of the stem, I cut the stems shorter. I used smaller pots and didn’t tamp down the potting mix. I learned to cut the stems at a slant for more surface area and to cut the leaves in half to encourage them to put their energy into reproduction rather than photosynthesis and leaf enlargement. 

    This week I noticed some little leaves growing up at the base of the old ones in both batches. 

I took the pots out of their plastic bags and gingerly dug out the mother leaves. Voila! There were little plantlets growing from the cut ends. The new leaves were no more than a quarter inch long, some much smaller, but they had their own roots. 

 

    I pulled the babies away from the mother plant, doing my best not to break them. I planted the best ones in a recycled six-pack from last year’s garden center annuals, 

encased them in another plastic bag, and replaced them under the grow light. With luck, I’ll have reasonable-sized plants to enjoy or share next winter.

    The non-peat potting mix did its job just as well as the peat-based mix I used to use. Score one for sustainability.

Learning to love shade

When I moved into a new house in 1985 and started my garden, I was disappointed to find that my fifth of an acre lot was mostly shady. The Norway maples in the curb strip effectively shaded our small front yard. In back, we had mature trees to the west, north and south, leaving a patch of lawn between the back fence and the house that got sun in the middle of the day. My first attempt to grow flowers was in that patch of sunnier ground. 

I wanted to grow roses and sun perennials. It took a long time to recognize that I was gardening in shade, whether I liked it or not.

            Some of the trees around the yard were on our property, so we could have cut them down. For each, there was a reason why we chose not to. A line of droopy Norway spruces blocked our southern exposure, but they also created a privacy barrier between our yard and our neighbor’s house. Next to the garage stood a red oak that an arborist guessed was at least 100 years old. Was I really going to evict every creature that depended on that venerable tree? Behind the fence to our west was a thicket of Norway maples rapidly growing from seed on our neighbor’s land.

            So shade gardening was my fate. I learned to love a lot of woodland plants and to seek out attractive leaf forms, textures and variegations. 

 Then we got a surprising opportunity to expand our lot to a third of an acre by buying some land from the neighbors behind us. After we cut down the Norway maples around the perimeter of our new land, I had something I’d never expected—a place to garden in almost full sun.

            But instead of putting in those English-style deep perennial borders full of sun-lovers, I went out and planted a lot more trees. We wanted a visual barrier along the back of the new lot, so we built a berm and planted evergreens including white pines, a balsam fir, and a blue spruce. I really wanted a gingko and a dawn redwood. For understory trees I had to have a stewartia, magnolias, redbuds, shadbushes, and witch hazels. By the time all that planting was done and the trees put on some height, my sunny garden area was mostly gone.

            I enjoy the variety of foliage that my shady garden offers. Later I learned about some other advantages of shade. Those Norway spruces along the south side of the yard shade our house in summer, decreasing our air conditioning bill. The berm to our west planted with now-tall evergreens shelters us from winter winds. A lot of New England’s worst invasive plants don’t prefer shade, so I have less of a battle keeping them at bay. The plants I grow in shade need less maintenance than sun-lovers would. And I’m certainly providing lots of shelter for animals, from insects on up to mammals. 

Compost: Keeping it slow

In November 1985, I stepped into my new backyard eager to start a compost pile. How hard could that be? Reading Organic Gardening had convinced me that I could transform garden waste into “black gold” in short order. We’d just moved in, and the materials available were fall leaves, mostly from Norway maples that surrounded our lot and a huge red oak next to the garage. After doing my best to create a rectangular base layer out of leaves, I threw on some soil, added more leaves, and proceeded in that way. My pile didn’t have the vertical sides of the ones in the magazine diagrams. It was shaped more like a sand dune than a box.

            Despite my great plan, by the next summer the oak and maple leaves in my embryonic compost pile had not turned into lovely leaf mold. What I had instead was a pile of matted leaves. The mound had sunk to a third of its original size, and the leaves had clumped together in rough sheets, but they were still whole. Clearly there was more to composting than I’d thought.

            Over the next 25 years, I learned that making compost takes longer than the sixty to ninety days I’d been led to expect. I developed a lazy woman’s process that worked for me. I built two side-by-side chicken wire bins and later added two more near the vegetable garden. In spring, I mostly added grass clippings. In midsummer, I had less grass to compost and more weeds and prunings from the garden. In autumn, the lawn started growing again, and a huge volume of fallen leaves needed to be dealt with. I gathered up most of the leaves to use as mulch, but some made their way into the compost piles. At the end of the growing season, I moved vegetable stalks, spent annuals, and perennials cut down for winter from the garden beds to the piles. I could have sped up the process if I’d been willing to balance proportions of nitrogen- and carbon-predominant ingredients and turn and water the piles. It just seemed like too much work. If I just left them alone for two years, my piles did indeed yield real compost. Here’s a picture of one-year-old pile I started last year. To its right is the bin I just emptied onto the vegetable garden:

            I still had the feeling, though, that I wasn’t doing composting right. Starting in 2010, I went on a quest to learn from master composters. I attended a lecture about large-scale composting done at Battery Park in New York City. I toured my city’s yard waste composting operation. I consulted two local experts, a permaculture gardener whose method, reassuringly, was a lot like my own, and a neighbor who kept worms in his kitchen for vermicomposting and saved urine in jars for adding nitrogen to his outdoor compost pile. Finally I got my compost tested for biological activity by the lab at Soil Foodweb. The result: the slow, cold-composting approach I was using was good enough. There were lots of happy microbes in my finished compost.

            My slothful method had a side benefit. In addition to generating usable compost, it also helped give birth to a new perspective on my role in the garden. I didn’t have to make garden waste decompose, I could just relax, let the expert decomposers in the soil do their thing, and enjoy the benefits. “Compost happens.”

My journey toward sustainable gardening

This is a blog about becoming a sustainable gardener. When I started my garden 30 years ago, I quickly found that there’s a big difference between environmental principles formed in a warm house on a winter evening and realities of sustainable gardening when you’re outside with your rake and shovel. How-to books by experts make it sound simple. I’m writing this blog to chronicle what happens when you try out expert advice at home.

            Here’s where I’m coming from: I’m a suburban weekend gardener in Newton, Massachusetts, USA gardening on a third of an acre lot (pictured above in May). My main interest is in ornamental gardening, although I have a small vegetable plot. Over the years I’ve struggled with such questions as how to compost yard waste without making it a full-time job, what’s the most convenient and sustainable mulch, how to kick my peat moss habit and shrink my garden’s carbon footprint, what to do about my suburban lawn, how much watering is needed and environmentally acceptable, whether to resort to pesticides when insects like winter moth attack, how to react to invasive plants, and how to incorporate native plants into a garden that’s already stuffed with a majority of nonnatives. I plan to share some of my stories with you, hoping they'll help clarify your own priorities.

            If you’re like me, you started gardening to feel close to the earth and natural processes. Then you find that almost every gardening decision involves an environmental dimension.  Although each of us knows our environmental impact is small, we realize that cumulatively our choices add up to significant positives or negatives for the natural world around us. In the last five years, with a wake-up call from Douglas Tallamy's Bringing Nature Home, I've given up the idea that I'm the boss and decision-maker for my garden. I've switched to seeing myself as a member of my garden community. That means that other inhabitants--from mammals to insects and soil organisms--share the work, but also that my smallest actions affect the garden ecosystem.

            Most people who aren’t professional gardeners can't be purists; they choose a middle path between convenience and sustainability. If you aim for sustainable practices, love gardening, but have limited time and energy to devote to it, you and I are probably facing the same challenges.