FAQ:  Can I use potting soil for raised beds?

Using potting soil for raised beds is not so much a question of whether you can, but whether you should.  A product designed for a raised bed, added to a very large container, might work.  But the inverse is not advised.

Like many things in life, “one size fits all” may not be the best soil strategy for container-grown, raised bed, and open ground/row crop plantings. 

Soil has a number of functions.  It acts as a substrate to support plants.  Air, water, and microbes move through its pore spaces.  Nutrients are stored until needed by those plants.

But the manner in which that soil is contained (or not) may require some adjustments to ensure optimum plant health.

Roots need wiggle room

Think about your feet in a pair of tight-fitting shoes.  There is not much space for your toes.  Air doesn’t circulate very well.  Your feet may sweat a bit.

A plant in a container can experience similar problems.

For one thing, containers need to be portable.  That dictates a lighter soil than might be found in the garden or raised bed.

The confined space physically restricts root development, too.  So the lighter soil makes it easier for the plant to send out roots.

A typical container is watertight with a small drainage hole at the bottom.  Lighter soil helps move water quickly from top to bottom to prevent waterlogging. 

But this rapid drainage may also lead to less water retained – one reason to make sure your potting mix includes the moisture-holding properties of compost.

Raised beds are little different.  They are generally much larger than a container and do not have an impermeable surface between the bed and the native soil.

A raised bed is like a comfortable pair of boots – more room to wiggle toes, but still a confined space.  

Rain and irrigation water have the space to spread laterally before percolating down through the bed.  Roots are able to do the same.

But media mixes for planting beds often have wood chips or other materials added to improve drainage.  Because growing space is still confined in a raised bed, the soil needs to have a lighter density than the adjacent lawn or garden.

That garden soil can be much heavier because roots have unlimited space to stretch out to seek water and nutrients.  In the landscape, it needs to have the ability to support big shrubs and trees, too.

But do note that “heavier” is used here as a density comparison to the lighter potting and container soils.  A heavy garden soil is not desirable, either.  It requires amendment to lighten things up.  Otherwise, roots will not develop properly.

Assuming that garden soil is a good density, it might be likened to going barefoot – plenty of room to wiggle the toes.  Or, in this case, plenty of space to spread roots.

Make your own or buy pre-made

If mixing up your own container or raised bed media, know that compost can be substituted 1:1 for peat moss in your favorite soil recipes. 

And if using your garden soil as a base, sterilize in the microwave or under plastic before adding the compost.  Sterilizing compost will kill the beneficial microorganisms that make compost such an ideal soil amendment.

For readers along the U.S. East Coast, McGill does not make a potting mix, but we do offer a bulk landscape mix for raised beds.  Ask for it at your local landscape supply yard.

FAQ:  How does compost help soil?

Most of compost’s benefit comes from its organic matter content, i.e., decaying plants and animals.  This organic matter contains the carbon, nutrients, and beneficial microbes that make compost the perfect amendment for so many soil types.  How does compost help soil?

Compost is about 50-60% organic matter on a dry weight basis.  A bit more than half of that is organic carbon.

This organic matter acts like a sponge, helping soil hold water and reducing runoff.  It also increases pore space to facilitate movement of air and water laterally through the soil, which creates transportation routes for microbes.

Compost is a soil conditioner.  Texture, moisture retention, and a host of other factors contribute to a well-conditioned soil.  A deep layer of light, friable soil encourages root development.  These root systems provide additional pathways for water and beneficial organisms. 

Healthy soil also provides a welcoming environment for those beneficial microbes, as well as other “critters” like earthworms.

The presence of active microbial populations improves nutrient uptake and contributes to the degradation of pollutants, too.  The combination of improved uptake and fewer nutrients lost through runoff results in a reduced requirement for synthetic fertilizers. 

For many growers, compost is the only amendment needed for a beautiful, abundant garden.

But don’t get carried away

Compost is a soil amendment – not soil.  Too much organic matter can be as bad as not enough.

Your target is a soil with a 5% organic matter content.  The best way to determine soil organic matter (SOM) percentage is with a soil test.

Soil testing is easy, inexpensive, and always a good move.  If you never tested your soil or can’t remember the last time you pulled a sample, this is the year.  Every three years is recommended.

You can buy a gizmo for a few dollars online or at the local garden center.  Make sure it tests for SOM along with moisture, salts, etc.

For about the same money, you can also use your local Cooperative Extension Service.  If you are not familiar with this excellent resource, we found this site which allows you to search for your county office by ZIP Code.

FAQ: When is the best time to add compost?

Anytime is a good time to add compost.  Fall, spring, mid-season – every growing space can benefit from the boost of soil microbes and organic matter.

Is one timing option better than another?

A quick scan of gardening articles and blogs seems to indicate a slight lean toward fall.  Putting growing spaces to bed for the winter under a layer of compost and leaves gives soil microbes plenty of time to prep the ground for spring planting.

But incorporating compost a couple of weeks prior to seeding or transplanting at the start of the growing season works well, too.

No time to wait those extra 14 days?  Go ahead and add compost to the soil at planting time.  Just make sure that compost is fully mature.  (It should smell “earthy,” like soil from the forest floor.)  An immature product could compete with seedlings for nutrients or even burn young plants.  An unpleasant, ammonia odor is a telltale sign of immaturity.

If the compost at hand is still a bit too fresh, incorporate some air by turning with a shovel.  Dumping a bag onto a tarp or into a wheelbarrow will add air, as well.  Let it sit a couple of days, then check progress.  Keep “fluffing” the compost until it’s ready for use.

And don’t forget to add a bit of compost to container mixes, backfill, and other non-crop uses.  Follow manufacturer instructions, especially about amounts to use.  Depending on the feedstocks that make up the blend, some compost products may be richer than others.  Here’s the link to McGill’s use recommendations.

Most plants will welcome a little mid-season pick-me-up, too.  Simply sprinkle a little compost on top of a container’s soil layer, use as a side-dressing for row crops, or add a dusting over lawns.  Water in or lightly rake.

Find a composting facility – then what?

As frustrating as it may be, even if you can find a composting facility near you, its presence may not guarantee your ability to recycle even the most common household organics.  Facilities that accept compostable resins are rarer still, and it might be best to buy recyclable plastics, instead.  

In the world of waste-related search terms, this one – “find a composting facility near me” (or some variant thereof) — is not unusual. People are actively searching for ways to recycle food waste, compostable serviceware and packaging, and other organics.  

Unfortunately, the fact that a composting facility may be operating near you does not guarantee your ability to recycle all organics via composting.

For individual households, composting options for food waste beyond the backyard may still be limited.  According to industry resources, more than half of the composting facilities in the US only accept yard waste.

Of those operations equipped to handle more challenging materials – like food waste – some will be large operations like McGill that specialize in services to high-volume generators only.

Other composting operations may be able to compost the actual food, but not the compostable plates on which it was served.

Relatively new to the industry are a growing number of entrepreneurs offering door-to-door food waste collection outside of the municipal disposal system.  Some transport the food to larger composting facilities; some will operate their own food composting systems.  But this is very much an emerging service, mostly in larger metropolitan areas.

Wish-cycling won’t make it so

Wish-cycling describes the practice of tossing anything designed to be recycled into the recycling bin, hoping someone on down the line will figure out where it is supposed to go.

Sadly, this isn’t the way recycling (including composting) works.  Until the day when scanners and robots take over sorting lines, households and businesses must pay attention to separation guidelines.

There is no such thing as a universal recycling mandate.  Every jurisdiction will have its own list of what can or cannot be diverted from the landfill or incinerator.

That list can depend on many factors.  Distance from the recycling facility, current prices for and availability of recycled feedstocks or recycling services, and other considerations influence the recycling options for any given community.

How do you find a composting facility?

Before grabbing that package of compostable cups on the grocer’s shelves, find out what is and is not compostable in your community.   

A call to City Hall or a quick web search will usually do the trick.  There are also a couple of sites maintained by national entities that can help you with that search:

Once you have determined what can and cannot be recycled/composted in your town, make a copy of the list and tack it up somewhere near your sorting and recycling bin area so there will be no excuses for convenient memory lapses.

Avoid cross-contaminating recycling/composting streams

More and more restaurants and groceries are separating their food waste from landfill-bound trash and diverting it to composting.

Do seek them out and spend your dollars with businesses with good waste habits.

But when dining or shopping at these establishments, don’t screw up all that good work by being careless with your own trash separation choices.

Clearing a tray by dumping everything into the food waste bin – including that aluminum soda can and plastic fork – contaminates the entire container. 

One aluminum can might not seem like much. It’s big and bright and can easily be spotted and snatched out of the pile some time before, during, or after processing … right?

Wrong.  When a truckload of similarly contaminated bins gets to the composting facility, that entire load could be rejected and sent to the landfill.    Feedstock contamination is a major problem for composting facilities.  It can damage equipment, diminish the value and reuse potential of the finished product, and impact worker safety. 

Tossing a compostable bottle in with the traditional plastics can cause big problems for those recyclers, too.  In fact, a single compostable item can ruin an entire processing batch of conventional resins.

Bottom-line:  Pay attention to the symbols and sort accordingly.

Buy goods that can be recycled in your community

Plastic waste has become something of a planetary nightmare.  But it’s the plastic that doesn’t get recycled that’s causing the biggest problems.

Here’s the truth:  It can make more recycling sense to buy a plastic cup that can be recycled in your community than a compostable one that cannot, because that compostable will only end up in the landfill.

To put an end to your household’s wish-cycling, shop smart.  Take that recyclables list to the grocery store and check recycling symbols before dropping a package into your cart.  If it can’t be recycled, choose a different product.  If your favorite fast food restaurant or coffee shop doesn’t serve their beverages in a cup that can be composted or recycled in your community, go somewhere else – and tell them why.

By practicing good buying and recycling habits, every household can do its part to reduce waste.  Just compost what you can and recycle the rest.

 

Whatever happened to aiming for the best waste management option? 

If it’s easier to do, then it’s the thing to do.  If the job can be done faster by cutting corners, go for it.  If it’s the cheapest option, buy two.  Somewhere along the path of societal evolution, easiest-fastest-cheapest has become synonymous with best.  This linguistic transmogrification is so pervasive, society no longer takes notice of its shortsighted slide down a spiraling path toward all things inferior.

When did easiest-fastest-cheapest become synonyms for best? When did we stop aiming for the best waste management choices and settle for inferior? 

There are good, affordable options out there that can strengthen/support recycling mandates and result in better waste management systems.  But progress toward zero waste is s-l-o-w and too many communities are still stuck in their comfortable ruts.

Progressive leadership looks to the future, ever-steering its constituency toward that proverbial “brighter tomorrow.”  For waste management, that horizon does not include landfills or incinerators. But it does include high-rate industrial composting … if public and private facility owners aim for the best and not the cheapest.

What are the best options for biodegradable wastes, the best organics collection strategies, the best composting technologies, the best facility designs, the best uses for compost products – who asks these questions before plunging head first into a development project?

Or, if someone asks the questions, do they really mean what’s the cheapest technology, design, and collection strategy? 

As for the resulting compost product, is the real objective to put it to highest and best use or to get rid of the stuff as easy and as fast as possible?

‘Best use’ is hard to achieve with an inferior product

Stormwater management, erosion control, carbon sequestration, turfgrass management, landscaping – these rank among the best uses for compost products.

They represent markets that place high dollar value on stable, quality soil amendments with no odor, high organic matter content, macro and micro nutrients, and other characteristics linked to a high-performance product that can be safely used by anyone, anywhere, at any time.

Poor quality compost cannot meet this minimum standard.  For the most part, its sale and distribution is restricted to low-dollar markets like farming and landfill cover.

The catch here is that, when managing mixed organic wastes, it usually requires a combination of the best facility designs, composting technologies, and management protocols to produce a really good compost product.

To achieve top quality, keep product moving out the gate, and ensure the highest possible revenue stream, a facility owner must match those aspirations with a high-quality manufacturing process and competent management that includes a professional sales effort.

Shortsighted strategies won’t meet long-term goals

Many communities are waking up to the fact that their long-range plan needs to include a viable strategy for organic waste management that keeps biodegradable materials – especially, food waste – out of landfills and incinerators.

Composting certainly fits the bill, and it’s often possible to modify an existing yard waste windrow permit to include other organics.

But what happens a few years down the road when that one load of food waste per week turns into a load per day, and then two loads per day, and then 10 loads per day?

When the entire city is source-separating organics curbside, and the vast majority of those garbage trucks are headed for that crowded, outdoor windrow composting facility, what happens then? 

Historically, facility owners (public and private) can struggle through years of banned feedstocks, failed lab reports, public complaints, unsellable product, fines, and/or legal fees before finally facing the facts. Their antiquated composting system simply isn’t up to the challenge of today’s urban waste streams … and their bargain basement facility wasn’t such a bargain after all. 

Successful high-volume processing of urban streams that include highly putrescible materials and biodegradable plastics requires tight environmental control and a high-rate composting process. 

If a facility owner wants to process in the least amount of space, taking the least amount of time, using the most reliable, predictable process, then that owner is going to convert that lesser system to the best system for mixed urban organics.  A covered and/or encapsulated aerated static pile (ASP) system, preferably with computerized control/monitoring and biofiltration, meets those expectations.

But how much might that region or business have saved/earned by investing in an expandable, high-rate facility in the beginning?  Remember, we’re not just talking composting, but all the dollars saved associated with compost use, too.

While Nero fiddled, Rome burned

Fiddling about while the city buries itself under a mountain of garbage is not an example of good governance.  In the private sector, failing to invest in upgrades and new technologies sets a company up for obsolescence.

Both depict outcomes resulting from failure to act when the time is right.

Unlike even 10 or 15 years ago, when most people were clueless about the many benefits of organics recycling on a municipal/industrial scale, today’s taxpayers are aware of composting as a waste management strategy.

Large volume waste generators in the private sector have been using commercial composting services for decades for one reason only – it’s more cost-effective than landfills.  As a bonus, it also gives corporations green points to use in their marketing messages.

Is it right for governing boards to continue to expect taxpayers to pay more simply because those who made the decision failed to be proactive in their decision-making?

No single option will be right for every community.  But giving serious consideration to organics recycling is always the right thing to do.

Starting at the top and working down is a lot easier than trying to claw one’s way up from the bottom.  So, aim for the best solution first, even if it’s not the easiest, fastest, or cheapest option.  

Then, use easy-er, fast-er, cheap-er tweaks to mold that system into the perfect waste management approach, customized to meet the unique needs and expectations of each community or business. 

Considering the pros and cons of waste management technologies?

Evaluations of waste management technologies can be riddled with inaccurate, incomplete, and outdated information – and the full dollar value of compost use is rarely included.

Elected officials making decisions on behalf of taxpayers may be experts in their respective fields.  But most lack knowledge in many areas specific to municipal governance, especially waste management technologies.  Consequently, staff and consultants are often asked to do some research and provide a report of findings, including recommendations.

A couple of articles released last month aimed a spotlight on inherent weaknesses in a process that relies on published research and interpretive reports for decision-making.

One piece focused on a study out of North Carolina State University.  It concluded the best use for compost was as landfill cover.  The other, from the University of Washington’s Dr. Sally Brown, said those research assumptions were off.  Many benefits of compost use weren’t considered.

No matter which viewpoint seems right to those who read the articles, the fact that there are two different takes on “best use” for compost – both from very reputable sources – focuses attention on one of the biggest struggles engineers and consultants face as they attempt to develop meaningful recommendations for policy-crafters and lawmakers.

A never-ending information stream floats about in cyberspace.  Available facts and bits of data are of sufficient quantity and quality to support almost any position one chooses to promulgate.  Adding or subtracting just one factoid in the mix of observations can result in a very different conclusion.

And the sad-but-true fact is that too many studies involving waste management systems fail to include the full range of economic and environmental benefits of composting.  Conspicuous by their absence are those elusive “dollars saved” numbers resulting from compost use.

Level playing fields for waste management technologies are hard to find  

Decisions related to organic waste management options present unique challenges.  Credible research comparing all four of the modern commercial technologies in the same study is rare.  Landfill gas-to-energy, thermal waste-to-energy, anaerobic digestion, and high-rate composting – finding a level playing field for technology comparisons feels like the impossible dream.

A researcher must wade through an ocean of irrelevant and often conflicting studies to find the few that fit the bill.  Volumes and types of materials may differ from one study to the next.  The specific parameters and amount of data collected won’t match up.  One report might focus on energy generation while skipping over input costs.  Others fail to include industrial composting and/or anaerobic digestion along with landfills and incineration or base conclusions on data that is now decades old.

Unfortunately, staff/consultants hired by municipal governments to gather information for these kinds of reports must rely on this mishmash of published data.  Rarely (if ever) does that consultant or in-house specialist have the budget to conduct new economic research comparing four different technologies at field scale using identical waste streams under real life conditions.

Hunting for needles in haystacks

A literature review may require the researcher to sort through a hodgepodge papers and websites to find information.  The hunt can include bench-scale studies, computer modeling outcomes, masters theses, field trials, magazine articles, and published budgets from public record projects. 

From this jumble comes the reviewer’s analysis, report of findings, and recommendations.  But proprietary information like construction and operating costs from privately-owned composting facilities is rarely available in the public arena.  As a result, a consultant’s report may not reflect an accurate picture of a technology’s true potential or the latest innovations.

In the real world, research scientists are limited by budgets, people power, time, personal knowledge, and the expectations of funders.  And while that may be the nature of the beast, the resulting scientific paper merely represents a snapshot of conditions and available data as they existed within the framework and specific timeline of the investigation – nothing more.

Scientists understand this.  But the elected officials using those study results to guide their decisions may not, taking those studies as gospel.  They don’t see inconsistencies or information gaps.  They don’t ask the right questions.

But if all of those studies ignored compost use, do any of their only-halfway-there conclusions really matter?

Getting waste management comparisons to the finish line

Just to see if it could be done, we took a stab at stitching together a balanced comparison of organics management options. Pulled the most recent data we could find from multiple studies.  Adjusted dollars for inflation.  Converted all energy input/output to a common unit of measure.  Cobbled together bits and pieces from a slew of research papers, municipal budgets, and other web resources.  

Tipping fee revenue was assumed for all technologies.  Commercial composting was compared instead of municipal operations because [1] we had a pretty good idea of the costs for building and operating a big, industrial composting plant and [2] many of the published costs we’ve seen over the years for municipal construction and/or operations for similarly-sized or smaller facilities were far higher than our own experience.

Based on a 100,000 TPY operation, annual revenue calculations included tipping fees and sale of products like energy and compost, minus debt amortization for facility construction (without interest) and operating costs per ton processed.

Admittedly, the resulting numbers were very, very crude.  But the grand total of those figures?  All options netted about the same dollars per ton.

Yeah.  We were surprised, too.  However, what none of the studies calculated – including our own investigation – were all the additional economic benefits to be had through compost use. 

Compost use tips the scale in favor of organics recycling

Sadly, the oversights of these reports were not unusual.  The full dollar value of compost use was missing from almost every published economic evaluation of waste management technologies for organics.  The absence of this highly relevant data represents a glaring hole in the big picture, one that can negatively impact an entire region for decades.

Mostly, these benefits represent dollars saved, which are much more difficult to identify and calculate than dollars spent.  But that doesn’t mean those dollar values should be ignored:

  • There is a dollar value for carbon sequestration through compost use.  
  • There are dollar savings in water treatment costs when runoff is cleaner because of compost’s filtration abilities.  
  • Construction projects save when they use compost-based controls for erosion.  
  • Turfgrass managers save when there is compost beneath players’ feet.  There is also a reduction in the severity of sports injuries … more avoided dollars.
  • When compost use is specified as part of a communitywide stormwater program, stormwater systems and their construction costs can shrink.  
  • During times when synthetic fertilizer costs are high, the NPK content of compost can represent a real bargain.  There are also avoided costs related to transatlantic shipping and synthetics’ reliance on natural gas.
  • Compost helps soil combat weeds and control some plant diseases, reducing chemical use on lawns and sports fields.

When a government body responsible for the general well-being of hundreds (or millions) of people is not provided with all the facts, their decision-making suffers.

Granted, it’s devilishly hard to assign dollar values to some of these benefits.  This article by Dr. Brown demonstrates how involved the calculation of even one aspect of compost’s advantages can be.

Yet, the greatest value of organics recycling comes not from composting, but from compost use.  Ignoring this fact serves no one and significantly undervalues composting as an option for mainstream waste management.

If a municipality wants to be assured of choosing the very best technology option for its organic waste stream, issuing agencies and departments will include those important “dollars saved” calculations on the list of deliverables required of their consultant or engineer.

True sustainability requires a system, not marketing-speak

Sticking a bird’s head on a spider does not transform that organism into a creature capable of flight.  Adding energy generation to incinerators and landfills doesn’t make them sustainable systems for organic waste management, either. 

“Sustainable” is one of those words that has been co-opted by Madison Avenue, slapped on everything from dog food to baby toys, and flung about willy-nilly like insults on nighttime reality TV.

It seems every product, process, and entity with even the smallest claim to the word uses it, because “sustainable” has finally caught the attention of the general public.

But the term, when applied to waste management choices, may be just as misleading as the words “natural” and “organic” on supermarket shelves.  What’s behind the label can still be the environmental equivalent of junk food. 

Admittedly,  people have become so adept at generating waste that the world has a never-ending supply have the stuff.  Ergo, any disposal or recycling technology could legitimately claim its feedstocks are sustainably sourced – even landfills without methane capture and plain, old incinerators.  

But that doesn’t make the total system sustainable or economically prudent or environmentally sound.

If pears are grown in compost in South America, shipped to Asia for processing, and transported back across an ocean to the U.S. for distribution and consumption, are those pears a sustainable choice?  

Using compost is better than not using compost.  But, c’mon, folks.  Did that pear earn the right to call itself sustainable?

Of course not.  Neither do disposal options that burn or bury compostables … even if they do result in energy generation.

Currently, only technologies that recycle or divert organics for use as a soil amendment (in farming, landscaping, turfgrass management, etc.) can claim true sustainability.  They close a loop, and when properly managed, do no environmental harm in the process.  

It remains to be seen whether some of the emerging re-uses for organic waste like building highways and formulating cleaning products will help or hurt the effort to recycle biodegradables back to the soil. 

Making new products from waste can be a swell idea.  But if those products can’t find their way to recycling at end-of-life, if the reclamation process renders them too toxic or otherwise inappropriate for composting, or if that reclamation generates a waste stream that cannot be efficiently returned to the soil, these types of reuse projects will likely – albeit indirectly – contribute to further soil depletion, more polluted runoff, increasing stormwater problems, and atmospheric carbon overload.

When government decision-makers are asked to evaluate new systems for organic waste management, marketing-speak has no place in a serious discussion.  One or two sustainable components does not make a sustainable system.

True sustainability cannot be conferred by feedstock source alone.   For organics, returning nutrients, organic matter, carbon, and beneficial microbes to the soil in an efficient, cost-effective manner makes composting and compost use a true sustainability choice – no marketing-speak required.

What’s the difference between compost and peat moss?

Compost is manufactured from recycled materials derived from plants and animals.  Peat moss forms naturally over many, many years – also from decaying plants and animals.  Both are rich in organic matter.  But it takes so many years for nature to form peat moss that the product is not considered “sustainable.”  Peat also tends to be too expensive to be used in large projects.  Fortunately, compost can be substituted 1:1 for peat in any media mix or soil recipe.  

McGill named to 2020 Influencers list

Thank you, Feedspot, for including McGill among the “Top 40 Compost Blogs, Websites & Influencers in 2020.”  We are honored to be one of the few industrial composting operations on the list.

Lab test lingo:  How much is 1 PPM?

Test results — compost analytical reports included — often convey constituent concentrations in parts per million (ppm) or milligrams per liter (mg/L).  Both state the fraction of the tested substance found per one million units of gas, liquid, or solid.

But what does that really mean?  Is 1 PPM a drop in the bucket or a thimble of water in an ocean?

Such infinitesimal amounts can be difficult to visualize, but here are a few examples found on the web that may help:

PPM

PPB

Sometimes, even smaller concentrations may be reported as parts per billion or micrograms per liter (μg/L).  When you see this term, correlate to:

Know the limits

One of the best analogies is 1 ppm equals one large mouthful in a lifetime of eating.  But it must be said:  just a small bite of the wrong thing can be one bite too many.

That’s why it’s important to always correlate reported concentrations  with the limits deemed safe by regulators and other jurisdictional entities.  Typically, for easy comparison, these ceilings will be reported in an adjacent column on the lab report.