Going peat-free

 I was encouraged to see a recent New York Times story about replacing peat-based potting mix with more sustainable materials. I just wish the writer, Margaret Roach, had gone farther and described her experience with the new materials.

Mer Bleue peat bog in Canada

    Peat has been the dominant ingredient in growing media for a long time because it’s great at absorbing water and nutrients but lets air and water flow through, and it’s slow to decompose. The problem is that peat is not a renewable material, at least on a human time scale. Peat bogs are giant carbon sinks, sequestering more carbon than all the trees in the world. Extracting peat from peat bogs releases carbon dioxide into the atmosphere, contributing to climate change.

    Peat forms very slowly when wetland plants decompose in oxygen-poor water. The peat we garden with took thousands of years to form. As we confront the climate emergency, we need materials for growing plants in containers that come without environmental degradation and a high carbon cost.

    When I learned about peat’s downside, I switched to making my own potting mix by combining sifted homemade compost with coir, or coconut fiber. This mix works just as well for my container plants as the peat-based potting mix I used to buy at the garden center. 

I combine coir and compost to make peat-free potting mix

     To make the volume of potting mix I need, I buy 5-kg compressed bricks of coir from a hydroponic growing outlet or Home Depot. You can also buy big bags of loose coir, but whatever kind you buy, it needs to have been washed to remove salts. To use it, just wet it by soaking in a barrel. Sounds like an easy solution, right? Unfortunately, coir comes with a carbon cost for shipping it here from tropical areas.

 

Container plants flourish in the peat-free mix

 
    From Ms. Roach’s article, I learned that US researchers are working on developing wood-based recipes for potting mix. Ideally, those could be made from local materials. She interviewed Brian Jackson, a professor at North Carolina State University and director of the Horticultural Substrates Laboratory. This is another area where Europe is way ahead of us. They’ve had wood-based growing media on the market for 30 years. Britain is moving toward banning peat in horticultural products.

An example of UK peat-free compost made from bark and wood

 
     Jackson’s team reports best results from a combination of peat and wood. Combining them creates a stable, spongy material that retains water especially well. It’s porous and provides lots of air space, creating an excellent environment for root growth. I’d rather drop the peat from the recipe completely. How about wood fiber combined with compost? That seems to be working in Europe.

     So far, wood fiber for growing plants seems to be available to large-scale growers in the US but not to home gardeners yet. While we wait, I recommend the coir-compost blend. But the best thing we can do as consumers is to ask garden centers to stock peat-free potting mix, whether it's based on coir or wood fiber. Why should Europeans get all the good stuff?

Being part of the solution

 To meet my environmental goals, I’ve been avoiding peat-based potting mixes and trying to cut down on buying plastic pots. As I plan next year’s garden, I’m thinking about how I can move this campaign up a notch.

Starting to envision spring lettuce

    Now that I know that peat is a non-sustainable resource, I’ve turned to coconut fiber, or coir, as the key ingredient in my seed-starting mix. I can live dangerously and use my homemade potting mix, which is half coir and half sifted compost from my compost bins. That mix isn’t weed-free or sterile. 

Coir and compost mix ready for summer containers

Or I can buy coir-based products such as Organic Mechanics Seed Starting Blend, made of coconut coir, pine bark, rice hulls, and worm castings, with no peat. This mix is pretty easy to find, and it works well for me.

    The next problem is the containers. I’ve got a collection of plastic six-packs for seedlings. Some I bought new—regrettably, I now feel. Others came with seedlings I bought at garden centers. 

 

A lifetime supply of seedling six-packs

I’ve washed and reused these, often through more than one seed-starting cycle. Eventually they tear and have to be discarded. 

    Last year I reached a turning point in my thinking about plastic pots. For years, the “green industry”—the businesses that produce and sell garden plants—have chosen plastic containers for their low cost, durability, and light weight. Now the industry can’t easily pivot to other materials, because they’ve designed their machines around the plastic pots’ sizes, shapes, and other physical properties. If they’d make a start, though, I bet lots of consumers like me would be willing to pay a few extra cents for non-plastic containers.

Even my local native plant shop uses plastic pots

    I was heartened by a recent Fine Gardening article about biocontainers. The writer, University of Georgia professor Bodie Pennisi, describes two types of biodegradable pots: plantable pots made of recycled paper plus or minus dehydrated cow manure, and compostable pots made from pressed coir. 

 

Coir pots

These are relatively durable and neat-looking. A more ephemeral product is a paper sleeve made from wood fibers that lasts long enough to contain flower and vegetable starts.

    Like me, you may have tried starting seeds in flats and pots made of pressed peat. I found these didn’t decompose as advertised. I plan to try starting seedlings in CowPots this year. These are the brainchild of a Connecticut farmer who’s been producing them from homegrown cow manure for 20 years. They’re said to keep their integrity for 12 weeks above ground. After planting, they should break down in one growing season, allowing roots to penetrate easily. The nitrogen in the decomposing cow manure reportedly gives the young plants a boost.

CowPots at Gardener's Supply

 
    For perennial divisions, I’d prefer longer lasting containers. I’m going to try pressed coir pots. I see that I can buy some from Greenhouse Megastore or Gardener's Supply, if not at my local garden center. I’ll report back on how these products work out.

 
    Now, how to do we get the garden industry to make the switch too?

Thanks, decomposers

With the May Day spotlight on under-valued workers, I’m grateful for the work of decomposers in the garden. Last fall I lamented my depleted compost supply. Now I’m rejoicing to see lots of fresh compost in my bins. This strengthens my impression that compost is like sourdough starter, full of what’s needed to reproduce itself. Once you’ve got the process going, it gets easier and quicker over time.

Under a layer of fall leaves in the bin, I found new compost

    That’s despite my lazy woman’s composting approach. I just pile on the garden waste as it comes. I don’t turn the piles or bother balancing the amount of “brown” high carbon and “green” high nitrogen materials. Compost still happens.

Adding fall leaves to a bin I emptied last fall

    Composting is central to my garden. With a renewed supply of compost, I’m ready to add some oomph to the perennial beds by improving soil from above—no need to dig in that extra organic material, because soil organisms will incorporate it.

Things go better with compost

    I’ll also save some compost for making homemade potting mix. By mixing it with coir, or coconut fiber, I make peat-free potting mix that works just as well as the bagged stuff I used to use for container plants.

Peat-free potting mix: because harvesting peat contributes to climate change

    In 2011, I had my compost tested for biological activity by Soil Food Web, a lab in New York. I highly recommend this experience. The lab reported the populations of the types of organisms in my compost sample: bacteria, fungi, protozoa, and nematodes. They calculated the ratio of fungal to bacterial biomass and observed that the compost was mature, bacterial-dominated, and becoming more fungal. 

     I even got a note, “One of the better compost samples I’ve seen in a while. Keep up the good work.” The only caveat: “Need to work on nematode diversity a bit more.” To that end, they recommended inoculating the pile with forest duff, the mix of half-decomposed material that lies on the forest floor. You can bet I did that right away.

Beneficial nematodes thrive on the forest floor

    Looking out at the thick layer of fall leaves I left on the beds last fall, I recognize that the whole garden depends on the same work these small organisms do in the compost pile. It’s often said that without the work of detritivores--animals such as earthworms that take in, break up, and digest dead stuff—and decomposers--bacteria and fungi that absorb nutrients from dead materials--we’d be living on top of huge piles of dead animals and plants.

    I don’t just count on these small organisms in the compost bins. They’re also hard at work building soil and turning fallen leaves into leaf mold. The wood chips that I spread on paths and around trees and shrubs last a long time, but they too are broken down, predominantly by fungi that can digest lignin, the polymer that makes wood rigid and resists rot. Without those fungi, I’d have everlasting mulch, but it would do a lot less for the underlying soil.

Wood chips would be around forever without decomposing fungi

    Composting is just a half-domesticated way of speeding up what’s happening all around us, thanks to those unseen workers.

As soil organisms break down fall leaves, they make good soil for spring flowers

Compost shortage

Once my composting operation settled into a routine, I could count on having two of my four bins produce a good supply of fully made compost every year. Every fall I spread a thick layer on the vegetable bed, where organic matter is used up fast by food-producing annual plants. 

Food compost from the closed bin will enrich the soil of the vegetable bed

When I planted new areas, I spread compost on the soil surface before starting to dig. When I learned that harvesting (really mining) peat contributes to global warming by releasing carbon, I started mixing finished compost from the bins with coir (coconut fiber) to make homemade peat-free potting mix.

     This year I haven't produced as much compost as I used to, and I'm going through it faster. Last year I gave away so many potting mix samples that I ran short of finished compost. 

Cute, right?

The reason for the samples was to interest garden club members I met in making their own peat-free mix. I thought if they tried mine, they'd see how easy it is to make a mix that looks, feels and functions a lot like commercial products based on peat. 

     Last year too I piled fewer fall leaves into the bins. I used to heap up leaves on the bins at the end of the gardening season, knowing the fluffy mounds would flatten during the winter, gradually decompose, and become part of the compost. But last year I went big on piling the whole leaves on beds to provide winter shelter for native insects.

Collecting leaves from the sidewalk to pile on garden beds

     Another call on my compost supply last year was the sheet composting project I started last March. The majority of the material for this composting-in-place soil improvement mound came from thick layers of wood chips and fall leaves. Thinner layers of compost were needed, though, to introduce soil organisms that would do the decomposing. I can see that they're doing their work. Already this fall the mound has sunk to about half its original height.

The sheet composting mound is sinking and starting to look like soil

     These extra demands on my compost economy have left the bins nearly exhausted this fall. Cutting down vegetable plants and emptying summer containers, I've started the process again in two of the four bins. According to the old system, though, the other two bins should be full of year-old developing compost. They're not.

The cupboard is bare

     In the past, I've just waited two years for the compost to be finished. Usually I make a point of adding garden waste to the compost as it comes, with no recipe. But I don't want to go through next summer with no finished compost. I may have to adjust my lazy-woman's composting method this year. 

     To get back on track, I can mix shredded leaves with the dead plants in the bins. 

Shredded leaves will decompose faster

Combining "brown" high carbon and "green" high nitrogen components will speed up the process. Desperate times call for desperate measures.

Pollinator-friendly container plantings

Every spring I fill 10 or 12 large containers with flowers and foliage plants for summer enjoyment. At this time of year, there’s a pause in the garden action. Foliage is looking shopworn and dull. A few flowering plants whose growth shut down during the hottest days are coming back to life, preparing for an autumn round of bloom. 

Phlox and a few zinnias are blooming in the late summer lull

Buds are swelling on the New England asters (Symphyotrichum novae-angliae), but few have opened yet. This seems like a good time to evaluate how the container plantings have turned out.

    My favorite pot this year was inspired by advice from reader Patricia McGinnis. Two years ago, Patricia pointed out that instead of neonicotinoid-treated annuals from the garden center, I could fill my pots with divisions of perennials from the garden. What a breakthrough!

    Last fall I’d potted some unneeded perennials with thoughts of passing them on to students at my spring sustainable gardening course (If you’d like to attend the fall course in my garden on Saturdays October 26 and November 2, you can register here through Newton Community Education). Some didn’t find a new home, so I used them to design a pot for a prominent position in the front yard.

Perennial divisions fill out a front yard container

    A purple-leaved heuchera, a nativar, makes a solid mass in this arrangement. Nonnatives provide contrasting foliage: a hosta with chartreuse leaves banded with blue-green and a Japanese forest grass (Hakonechloa macra) with similar yellow-gold coloring. I bought an ostrich fern (Matteuccia struthiopteris) to add some height and added white-flowered wax begonias to bloom nonstop through the season. The begonias' shiny round leaves add another texture to the composition. I knew the fern and begonias were neonic-free, because I’d gotten them at a local farm and garden center that promises untreated plants.

    My next favorite container plantings this summer feature nonnative combinations I’ve been repeating over the years. The “thriller” in these pots is Canna ‘Bengal Tiger’. 

Yellow-striped leaves make Canna 'Bengal Tiger' stand out

I store the roots in the basement through the winter, so I don’t have to worry about neonic-treated replacements. I do the same with the giant tuberous roots of elephant ears (Colcasia esculenta). 

Like cannas, elephant ears need their roots stored indoors in winter

The canna has orange blooms, but I usually cut off the flower stalks so top-heavy plants won’t tip over in a heavy wind. To fill in around the canna stems in a pot that’s located in shade, I added white-flowered impatiens. In two pots on the deck that get afternoon sun, I combined the cannas with cobalt-blue lobelia (Lobelia erinus). 

    This year I’ve had success with another conventional flower choice: a big pot full of apple-blossom pink geraniums. 

Taking a break on a geranium flower. Is it a cricket?

I’d bought three of these plants at a pesticide-free garden center two years ago. I’ve kept subsequent generations alive by taking cuttings in fall. This way I don’t have to search every spring for neonic-free geraniums.

    These are the adaptations that have allowed me to keep neonics out of my pollinator-friendly garden. I’m also happy that my peat-free potting mix is succeeding in providing sustenance for the container plantings.

Coleus thriving in potting mix made from compost and coconut fiber

Before the freeze

Come visit my table at Celebrate Newton, a holiday craft fair, on Sunday December 2 from 10 to 4.


Despite interruption by early snow, I’ve spent the past week hurrying to prepare the garden for winter. A list of chores always looms as the light for working outdoors shortens and the ground gets ready to freeze.

Snow already! Time to rush through the last garden tasks

    Number one on the list is gathering in as many fallen leaves as possible and spreading them around the garden. This fall I’ve reverted to shredding leaves to mulch the new perennial beds at the back of the house. I’ve been shredding less since learning that whole leaves shelter insects and other animals through the winter. 

Letting whole leaves lie for shelter

Last spring I found I had to peel back layers of whole leaves I’d piled on these new beds to uncover the emerging young perennials below. That would have been OK, but once those leaves were gone, there was no mulch left on the bare soil between plants. The thin layer of bark mulch I'd applied when I planted the new perennials had long since decomposed. Until the plants grow to full size, I think they'll need some shredded leaf mulch.

     Everywhere else in the yard, I’m piling up whole leaves. My neighbor Pat kindly donated her bags of raked leaves. I go out periodically and collect leaves from nearby sidewalks and gutters, piling them on a tarp to drag into the backyard. 

Precious cargo

At this point, the drifts of fluffy leaves look way too deep, but I know they’ll settle to a reasonable layer of a few inches as the winter comes on.

    I’d hoped to use potting mix from the large pots that hold my container plantings to layer on top of the grass where I’m planning to enlarge a bed. Cold weather came too soon, though. Starting that new planting area with layers of cardboard, wood chips and compost will have to wait until late winter, when some tree pruning should provide me with a big pile of wood chips. 
  
    Frost reminded me to move hoses and watering cans into the garage or basement. 

Time to put away the hoses

The last job of all will be to wash the large ceramic and plastic pots and move them indoors. Freezing and thawing outdoors through the winter shortens the lives of pots and hoses. I eventually store all the pots in the basement but never get around to washing them until the garden is completely dormant.

I'll wash ceramic pots and store them in the basement--eventually

    A few end-of-fall tasks prepare for indoor gardening. I sifted finished compost from one of my piles, transferred it to a bucket, and ferried it into a large plastic garbage bin in the basement. There it’s available to mix with coir—coconut fiber--for making homemade potting mix. I’ll use that to proselytize for moving beyond peat-based potting mix, giving out little sample bags when I visit garden clubs.

    Saturday I picked out amaryllis bulbs at the garden center. With compost and coir in the basement, I’m ready to pot those bulbs in peat-free potting mix. We’ll enjoy their giant flowers in the warm kitchen while winter rages outside.

Amaryllis flowers light up the dark months-photo pizzodisevo

While the weather outside is frightful

Outdoors it’s winter, but plants still grow and even flower indoors, despite short days. During winter, I try to nurture houseplants in a sustainable way by limiting turnover, minimizing use of materials with high carbon cost, and carrying over outdoor plants that can make it through the winter next to a window or under lights.

Geraniums and succulents making it through the winter under a grow light

    Some of my houseplants may be older than my children. I can’t resist treating them like pets and keeping them even when they aren’t beautiful. This winter I’ve added some pretty young variegated ivy and a fern to the collection. 

Variegated ivy can thrive indoors and out

I’ve had good luck transplanting low-light selections like these in spring to a large box planter in a shady area. This way I can enjoy their foliage through both the winter and the summer. The fern will succumb to next fall's frost, but the ivy may tough it out and become a perennial.

    Winter blooms of African violets, orchids, paperwhite narcissi, and amaryllis will add some welcome color to this mostly green scene.

African violets blooming in February

    I also rooted cuttings from some of the neonicotinoid-free geraniums, coleus, begonias, and rosemary that I bought last spring to plant in summer containers.

 

A confused geranium blooming this week

It was difficult to find plants that hadn’t been sprayed with the pollinator-toxic insecticides. I’ll be able to use the old plants’ descendants next year and avoid the search for untreated plants. The youngsters aren’t going to get me into House Beautiful, but I think they look cheery under a grow light in the kitchen/family room. They’re located where I can’t miss seeing them, so I notice when they need care.

    By recycling plants from last summer, I avoid the carbon cost of new plants. This can be considerable, because they often travel to local garden centers from remote parts of the country and the globe. I also reuse the plastic pots and six-packs that my plant purchases came in. 

Ready for starting seeds in early spring

Washing the soil out of these and storing them in the basement is a winter activity. Like the indoor bulbs, cuttings from summer plants are grown in homemade peat-free potting mix. By using this growing medium instead of commercial potting mix, I spare the peat bogs, which sequester much of the world’s soil carbon.

    I’ve long had a fantasy of enclosing a small porch at the side of the house in glass to use as a greenhouse or conservatory. 

The conservatory at Tower Hill Botanic Garden

In addition to the cost, a concern that holds me back is how I’d cope with infestations and plant diseases indoors. The greenhouse manager at the Arnold Arboretum once told me that they emptied the greenhouse once a year to clean it thoroughly and spray it with diluted chlorine bleach. The prospect of donning a hazmat suit and mask to spray an indoor space with chlorine or other toxic pesticides cooled my enthusiasm for a greenhouse attached to our living space.

    Unlike the Arboretum staff, I’m not growing irreplaceable specimens. If indoor plants get sick or attract insects, they’ll find themselves filling another sustainable role—as compost.

Happy holidays, inside or out!

 

Life support

With the first snow this week, my spirits plummeted. Winter is really here, and I wish we could fast-forward to April 1st.  

Not this again!

Since we can’t, it seemed like a good time to plant some indoor flower bulbs to get me through the cold, dark months.

    My bulb choices this winter are paperwhite narcissi (Narcissus papyraceus) and amaryllis (Hippeastrum species).

Paperwhites have a lovely scent-photo by Ceasol

You really can’t fail with these bulbs, which contain everything they need for flowering when you buy them. 

You can't beat amaryllis for big beautiful flowers in the dead of winter-photo by pizzo disevo

A bulb is a storage mechanism that allows the plant to get through dry periods. It’s made up of embryonic leaf, stem and flower tissues surrounded by fleshy scales that contain food stored up during the plant’s growing period. An onion is a bulb too; the rings of flesh are its storage scales.

    Once you plant them and they start taking up water, bulbs send out roots from their base plates, and stems start to extend upward. They’re going to do it whether you help them or not. In fact, unplanted bulbs start putting up flower stems if I leave them in the basement for too long before planting them. 

    I prefer to pot the paperwhite bulbs in homemade potting mix. I make the mix by combining coir (coconut husk fibers) with compost from my compost piles to avoid using peat-based medium, which is not a sustainable product. I find that paperwhites grown in the potting mix stay more upright than bulbs grown in bowls of pebbles.

Once covered with potting mix, the bulbs can be watered and set in a cool, dark basement spot for a week or so until they start sending up new growth

    Amaryllis bulbs are gigantic. The one I planted weighed more than 15 ounces, with a diameter of 5 inches. 

Hubba hubba!

I usually get four flowers on each stalk. A second stalk often emerges a few days after the first. I nestled this bulb in a pot just wider and taller than itself. Only a little potting mix was needed to fill in the remaining space. 

I set the amaryllis pot next to a radiator to help it start growing. I'll move it to a cooler windowsill once the flower stalk starts extending

    Anyone who has a window with a bit of sun can get flowers from these bulbs. The harder challenge is to get them to flower again the following year. The paperwhites originate in the Mediterranean. They need a warm climate and won’t survive in New England gardens. For us, they’re annuals.

    It’s tempting to try to get amaryllis to rebloom. In their natural habitat in South Africa or South America, after flowering the bulbs would soak up sun and soil nutrients for a couple of months before dropping back into dormancy, waiting for the signal to flower again. It takes a lot of sun to pack in the same amount of stored energy in our area. Here are some instructions from the National Arboretum.

    My experience has been that with lots of trouble, I can get amaryllis leaves to grow the next year and, rarely, one small flower cluster. It’s not worth it. I pay the $15 for the big bulbs and throw them on the compost pile when they’re finished blooming. All good things have to end—and winter does too.

Doing something about the weather

I thought snowdrops blooming this week were the earliest I’d recorded, but looking back I see I spotted some on January 31 in 2012, another winter with very little snow.

Snowdrops are blooming early

In recent years, I’ve noticed spring growth starting earlier. Scientific data confirms this trend is affecting wild plant populations. Our climate is changing, and gardeners are on the front lines.
 

Witch hazel buds are already opening

     I’m finding the lack of snow cover ominous this year. Is this the new normal? Last year demonstrated the kind of damage that our plants suffer when they experience blasts of cold weather without the insulating protection of snow.

    The New York Times recently reported that farmers in Kansas are talking about changes in the weather, although many still don’t blame human actions for causing global warming. One farmer they spotlighted also spoke about sequestering carbon in the soil. On a much smaller scale, that’s something we can do too in our backyards. 

     Brooklyn Botanic Garden offers The Climate Conscious Gardener, a handbook of useful approaches for minimizing the carbon footprint of your garden and sequestering carbon in your soil and plants. 

    With Congress and the Trump administration rolling back restrictions on methane leaking from oil and natural gas rigs and wells, it’s even more important for us to seize the opportunity to be good climate stewards. 

     Methane is a greenhouse gas 21 times more potent than carbon dioxide. Federal regulations restricting its release were intended to fight climate change. Now with climate change deniers having their way, oil drillers and frackers hope to be spared the trouble and expense of preventing methane release. The planet and everyone on it will pay the price.
 

Gas flare from North Sea oil drilling--photo by Varodrig

    Some of the steps the BBG handbook recommends:

Planting trees. We’ve all heard about this as a way to keep carbon out of the atmosphere. Long-lived trees are best.
 

The dense wood of this tall white pine sequesters lots of carbon

Siting trees and shrubs to provide windbreaks and shade. This will reduce your house’s energy needs for heating and cooling—and save you money. 

Minimizing digging or, even better, switching to no-till gardening. When we dig, we introduce oxygen that speeds up decomposition of organic material, releasing carbon into the air.

Recycling fallen leaves and garden waste as compost. When you keep organic material at home as compost, you’re holding onto carbon. 

Applying organic mulches. Mulches made from materials you can get close to home are especially carbon-thrifty. I like to mulch with shredded or whole leaves and arborist wood chips.
 

Wood chip mulch holds carbon

Shrinking your lawn. Every other landscape feature requires less energy, petrochemicals, and water for maintenance.

Skipping peat-based potting mix. Peat bogs are a major carbon sink, sequestering more carbon worldwide than trees. When peat is extracted, carbon is released, and the carbon sink it provided is lost. It’s easy to make homemade potting mix from compost and coir (coconut fiber).

By following some of these recommendations, we can be part of the solution locally, even when the federal government is going in the wrong direction globally.

Neck deep in the Big Muddy