For over 90 years, Lambert Peat Moss Inc., a family-owned business, has been acknowledged as a leader in the sphagnum peat-based products industry. Its devotion and passion make it the perfect partner for your business whether you are a professional grower or an amateur horticulturist. Well-known for its ability to quickly adapt to the customer’s requests and special needs, Lambert’s success is based on its pre-occupation for quality control and consistency of its products. More than ever, growers are looking for specific products to help them stand out, including crops that often require particular growing conditions.
In order to transcend and meet the needs of its clients, Lambert offers the possibility to customize all its Standard Professional Peat-Based Substrates and gives the option to custom blend virtually any formulation that suits the grower. Depending on the characteristics that the producer is looking for, customers can select the peat grade, adjust the pH (up or down), include a different moisture content, a nutrient charge, an organic-approved input, biologicals or disease-suppressive products. Lambert can provide endless possibilities to fulfill any grower’s expectations and assist retailers to develop their own private label of retail potting mixes and landscape soils for the horticultural market.
Quality is Lambert’s priority
Lambert’s in-house quality control laboratory performs continuous sampling and analysis during the production of the mixes. Agronomists and engineers have developed rigorous standards and procedures to make sure that every cubic foot of product leaving the yard complies with the company’s strict standards. Quality control procedures are regularly re-assessed to increase the product’s quality. To comply with chemical standards, samples of products are constantly analyzed for pH and EC. Particle size distribution, porosity, moisture content and the yield and firmness of our bags are frequently measured. Finally, random greenhouse tests to evaluate our product performance are processed frequently.
The true pillar of Lambert’s success is its people. Experienced agronomists and soil technicians are always ready to help and guide customers with any questions they may have. Our sales team includes industry veterans who truly love what they do and strive for customer success. During this pandemic period, customer service is even more important. Even though it may not be possible to physically visit growers and retailers, the team is available to answer any questions or perform follow-ups regarding targeted results or to calibrate some aspects of the substrate using different virtual meeting applications. It works surprisingly well and gives the customer a quick follw-up.
The Lambert family and its employees take great pride in providing the highest quality of peat products and peat-based mixes while simultaneously nurturing the land that it harvests from.
From this family to yours, it is an honor to be at the root of your success!
Green industry experts weigh in on the 2020 sales boom, predictions for the coming year and what that means for growers in terms of operational spending.
The green industry is coming off a hot streak as we kick off the new year. Operations across North America, save for a few regions where lockdowns didn’t exempt growers, saw historically positive sales volumes last spring, stretching into summer and fall.
Now that the wild and seemingly never-ending 2020 is firmly in the rearview, many horticulture operations that are flush with cash find themselves at somewhat of a fork in the road: is it wise to take advantage of grower-friendly finance rates and invest in expanding production to meet the new demand we saw in 2019? Or should they pay down debt and prepare for the possibility of yet another economic downturn? Hold market share and keep on keepin’ on, hoping for better days ahead?
Of course, many believe that any decision in this regard should strongly consider that the virus appears likely to stick around with us at the very least through yet another spring production season.
So, is 2021 the year for growers to make some big moves?
2020: outlier or new normal?
Mintel is a well-known market research firm that has been tracking and reporting on all kinds of consumer trends throughout the COVID-19 pandemic. The group conducted green industry focused research this summer, finding that 84% of American consumers are spending the same or more time in the garden than before the pandemic, and 10% have increased plant purchases from the year prior.
Purdue University’s Ariana Torres, an associate professor in the school’s ag economics department, warns not to read too deeply into those numbers, however.
“We believe that this is more due to a regional-specific effect, and we are finding evidence that non-essential shopping (including plants) has actually decreased. Consumers are feeling less confident about the growth of the economy going forward,” she says.
That said, Torres is seeing a significant shift in how people acquire plants, and greenhouse operations are also looking for new customers and markets.
“Data from the [Mintel] tracker also shows that 36% of plant purchasers are buying more online, and one way growers can address new and complex industry trends is to aim direct sales as much as possible,” Torres says. “Today, you’re seeing that happen with many growers that previously were only selling wholesale now trying to bypass the traditional brick-and-mortar retail route to market by selling to consumers online.”
Torres says that since March, a bunch of new businesses have sprung up as a response to the online demand to deliver plants, flowers and other green products directly to consumers.
“And retailers that were not traditionally plant-purchasers (e.g. Aldi) have agreed to support farmers and local centers and channel their products through this retail market,” she says. “Using social media marketing and other types of digital marketing can help business reach local customers in a cost-efficient way, often without a large up-front capital investment.”
Associate Professor Ben Campbell lectures on applied economics at the University of Georgia’s Department of Agriculture. Campbell himself advocates a restrained approach when it comes to the long-term investment and expansion question going into 2021. His own market research in 2020 revealed a mere 4% increase in consumer spending on plants compared to 2018 levels.
“I myself am a very risk-adverse person, and there are just too many uncertainties right now with coronavirus and what will happen with consumer buying next year,” he says. “There’s some optimism about a vaccine, but the odds of us having it by spring 2021 are not great. Right now, I just don’t think we’ll see the same plant-buying boom that we saw in 2020.”
Campbell foresees more people returning to their normal office work routines, and more unemployed workers without the same unemployment compensation safety net they had in 2020, contributing to a return to pre-pandemic plant demand. Or possibly even lower levels of demand.
“Unless you have a local market already set up, and the demand is there and it is firm and stable, I would be very concerned about how 2021 is going to go from a sales standpoint, and I’d want to watch what I am doing as far as expanding,” he says. “We’re probably not going to have 2020 happen again in 2021, at least not anywhere near the size or scale that we saw. And if everyone expands their operations at the same time, we’ve seen in the past that can have a compressing effect on prices, and then demand likely will go down. That’s a big double whammy.”
Texas A&M University professor and Ellison Chair Charlie Hall does not envision 2020 sales levels becoming the new normal in horticulture, either.
“Are all of the ‘newbies’ going to come back for a second helping of this whole lawn and garden thing?” Hall asks. “A big part of that is whether they were successful or not with their plants. If they were successful, then sure, maybe. At the same time, it’s not like I’d be building 50 acres of greenhouses right now expecting this giant tidal wave of demand to be there.”
Hall bases that analysis on preliminary data from independent garden center pre-bookings for the upcoming spring season.
“Right now, including the lawn and landscaping side of the industry, it’s looking like we’ll probably see something in the neighborhood of about a 10% bump in demand from pre-pandemic levels,” he says.
Prepare for a much different 2021 season and be ready to adjust on-the-fly.
Consumer spending habits are evolving
Economists across the board are sounding alarm bells on what businesses can and should expect to happen in 2021. Federal Reserve Chairman Jerome Powell recently cautioned that the economy is likely to shrink substantially across both the first and second quarters of the new year, with unemployment projected to increase up to near the 10% mark.
A “double-dip” recession would potentially have devastating consequences for the green industry. Generally, when consumers lack confidence in the economy, they save money and pay down debt while decreasing discretionary spending on goods and services until the economy recovers, or a stimulus is disbursed.
One of Hall’s many fortes is analyzing consumer spending trends and making sense of what those trends mean for the green industry, and more specifically, for growers themselves. Looking at the data of late, Hall is seeing a near future featuring less consumer spending on things like plants and flowers and trees.
“Durable goods purchases have been extremely strong (during the pandemic) and consumers are still spending money on durable goods, some of which we attribute to the last stimulus payments putting a little extra cash in people’s pockets,” Hall says. “In most recessions we do see a bump in flower and other plant sales early on in the recession, but once the recovery starts consumers start spending more on durable goods, and there’s less to spend on flowers. It seems like that’s where we’re headed right now.”
For her part, Purdue’s Torres agrees that we will likely see a drop in consumer disposable income outlay during this second wave of the pandemic.
“Over time we will likely hit a demand-supply equilibrium, and it is better for growers to behave conservatively by paying off their debt with the highest interest, investing in cost efficient equipment, automating activities and processes, and reducing costs and increasing efficiency,” she says.
Even with Americans’ discretionary fund spends likely to decrease in the short term, there are a couple positive developments that Torres thinks could help soften whatever blow the industry ends up absorbing.
“Plant demand from the baby boomers is increasing, and this segment of the population has spending power and is prioritizing local purchases and purchasing online,” she says. “And private home improvements continue to increase due to the fact that Americans are spending more time at home and prioritizing quality of life and gardening more.”
Torres also believes a strong and only growing stronger real estate market will continue to prop up demand for plants and new landscape features, benefiting garden centers and growers alike.
Labor a constraining factor, too
Long before anyone knew what the coronavirus even was, the green industry’s labor situation has long been singled out as the top constraining factor for growers looking to scale up.
“If you expand production and invest in new structures, then you’re going to need that much more labor,” Campbell says. “But the question still remains for many growers: Can you get it?”
The ag labor pool was essentially taking hits from all sides in 2020. Global travel restrictions made an uber-competitive immigrant labor pool that much tougher to maneuver, and laid off domestic laborers largely stayed home and collected the $600 per week Pandemic Unemployment Assistance (PUA) payments rather than take lower-paying, manual labor-intensive positions in farming.
These developments are only going to continue to exacerbate, according to Torres.
“Labor issues are becoming larger due to the pandemic,” she says. “Labor is one of the most important and expensive inputs for industry businesses, and it promises to remain a major worry due to lack of mobility, government unemployment payments, and immigration issues.”
Therefore Torres, while reminding growers to be smart and conservative and analyze any investments accordingly, does advocate they take a close look at adding automation technologies where they fit.
“As we go through this pandemic, it is important for business owners to find technologies that reduce labor needs,” she says. “Automation of activities, tools and technologies that improve the quality of products and services, and new processes that can spread or reduce the need for labor, should be prioritized.”
Caution moving forward
All three green industry economic experts we consulted independently offered growers the same advice: a conservative approach today could actually be more beneficial in the long run, versus a frenzied plan to expand in the immediate short-term.
“Having a conservative approach with the recently experienced liquidity can pay off later on,” Torres advises. “And it appears that the best route forward today involves investing in economically feasible technologies that promote automation, and most importantly reaching out to consumers directly through online sales and uncovering new or non-traditional markets.”
She also believes growers should “prioritize cash flow health in the long-term” while trying to diversify their offerings into new or emerging crop markets like indoor strawberry production, or hyper-local vertical produce farming.
Campbell advocates much of the same risk-adverse go-forward plan as Torres, and he had been keeping a keen eye on the 2020 U.S. presidential election since the results have a direct effect on the economy.
“There is a lot of research and data out there that shows the economy tends to slow down coming out of an election, and when people are uncertain and don’t know what to expect from a new administration, they save rather than spend,” he explains.
Perhaps the industries’ foremost voice on economic analysis and issues, Hall cautions growers not to get complacent and contented after many had their finest spring sales seasons in decades.
“Make sure you’re lean and make sure you’re efficient in everything you do,” he urges. “If another downturn is coming then I will generally tell people to defer large capital expenditures, defer maintenance expenses as much as they can, forget paying dividends and pay your suppliers within terms, meaning if you have 60 or 90 days to pay off a balance, then go ahead and take it. You do not have to pay everything off within 10 days.
“And making full use of any available lines of credit,” he adds. “Is usually a good strategy, especially considering that during the last great depression if growers didn’t use those lines of credit the banks clawed those limits and rates back from them.”
Bottom line? The path ahead for the next few miles seems unclear at the present time. Perhaps there are more good times on the horizon, yet the prospect of more danger could lie just ahead. However, you decide to play your hand in 2021, like any seasoned gambler, be sure to do your homework first.
Matthew J. Grassi is managing editor of sister publication, Greenhouse Management. This article originally appeared in the January 2021 issue of Greenhouse Management.
Abies concolor white fir thrives in moist, well-drained soils.
John Muir, one of America's most famous and influential naturalists and conservationists, once called white fir (Abies concolor) “a charmingly symmetrical tree” and went on to state "the noble grandeur of the species is patent to every eye." Those that know this conifer undoubtedly appreciate the inherent beauty of the large, silvery blue needles that give such a lasting impression in the garden 365 days per year. Primarily native to mountain slopes (3,000-9,000 feet in elevation) in the Western United States, this fir has broad adaptability in other regions of the country if given proper siting and consideration. White fir is considered one of the best firs for the Midwest and has increasing use as a substitute for the Colorado blue spruce (Picea pungens) which has been frequently overplanted and suffers from an array of ailments. While the species, subspecies and some selections of white fir will attain significant heights in time, there is an exciting array of more compact and restrained varieties that lend their toughness and ornamental qualities to the smaller-scaled landscape or tight spot in the garden.
Prior to promoting some of these exciting selections, it’s important to talk about this species and how it best will thrive in the landscape. As the most drought tolerant of the firs, it is important to make sure that you have good drainage in your potential planting location. White firs do best in deep, rich, moist and well-drained soils and prefer a slightly acidic situation if possible (although slightly alkaline is acceptable). Abies concolor, while adaptable to gravelly soils, will not thrive in heavy clay soils and excessively wet sites, and areas that might be prone to early frost (“frost pockets”) should be avoided as this fir breaks bud early and can suffer some damage from early frosts.
Tolerating not only drought, white firs can also handle the heat and cold. White firs have relatively few insect and disease problems and are rarely browsed by deer. Hardy from Zones 4-7, this species prefers locations with long winters and cool summers and shouldn’t be used where lengthy heat and humidity are factors. Positioning white firs in full sun is ideal although they will tolerate partial shade. The best blue coloration on the needles will occur in full sun locations although is also related to the specific variety. The soft, flattened needles (1½ to 2½ inches long) emerge light green in spring and attain their summer coloration in short order. Both sides of the needles are the same color, hence the specific epithet of “concolor.” The needles are spiral on the shoot but are upswept across the top of the shoot in flat ranks. Crushed needles emit a lemony scent. Although most selections are consistently a decent blue in summer, the two larger selections of white fir, ‘Candicans’ and ‘Blue Cloak’, are thought to be among the bluest of conifers although their ultimate mature size removes them from the primary focus of this article. Cones are rare on white firs and tend to appear with age.
Abies concolor ‘Blue Cloak’ is thought to be one of the bluest types of conifer.
While the growth rate for white fir is slow, the straight species and some selections will ultimately reach an average height over 40 feet with a width of 15-20 feet in the landscape. This classic, conical form is very symmetrical with the top half of the branches appearing slightly upswept and the bottom half of the tree featuring downswept branches. As with any larger conifer that gains significant size, having the proper location is vital. Our landscapes are all filled with errors of judgment in terms of plant placement with little foresight into the maturing sizes of these woody plants. With so much ornamental value to Abies concolor and various selections, evaluating reduced-size selections makes sense and allows for a broader applicability in smaller landscapes, rock gardens and areas that simply don’t have the space for a larger form. As mentioned earlier however, if you do have space for medium to large versions of white fir, consider the straight species, ‘Candicans’ or ‘Blue Cloak’ for superior blue coloration.
If a narrow form of white fir is needed as an exclamation point in the landscape or to anchor a tight spot, the selection ‘Conica’ is excellent. Slow growing and narrowly conical, this dense and strongly fastigiate variety has shorter branches (and needles) but offers the same contribution of powder blue every day of the year. This selection will maintain a central leader and light shearing on new growth in late spring can be accomplished as needed to maintain a desired size. If a shorter, upright form is of interest, consider the selection ‘Archer’s Dwarf’. This 1982 introduction is quite uniform and symmetrical with similar features to ‘Conica’ but on a reduced scale. While very slow growing, the intensity of blue on the needles of this selection is admirable. While still narrow but with a weeping form as well, the selection ‘Gable’s Weeping’ adds significant interest, texture and character with irregularly weeping branches with no two specimens looking identical.
Abies concolor is named so because the needles are the same color on each side, hence “concolor.”
While not a comprehensive assemblage of dwarf cultivars of Abies concolor, there are some excellent selections available although an aggressive search may be required. The slow growth rate coupled with “patience in propagation” will undoubtedly expand the offerings of these compact selections in future years. Incidentally, from a Midwest perspective, there are excellent conifer collections to include many of these varieties at Hidden Lake Gardens (Tipton, Michigan), the Dawes Arboretum (Newark, Ohio), the Bickelhaupt Arboretum (Clinton, Iowa), the Chicago Botanic Garden and Dubuque Arboretum & Botanical Gardens (Iowa) to name just a few.
With my 21 years at Rotary Botanical Gardens, I saw many developments at this 20-acre botanical garden in Janesville, Wisconsin. This also included the addition of a dwarf and miniature conifer collection in 2005. The most asked about plant in that collection has been the ‘La Veta’ compact white fir. Positioned adjacent to the golden foliage of a ‘Princeton Gold’ Norway maple (Acer platanoides), the crisp blue of the needles really pops. The location of this specimen along a path encourages visitors to reach out and enjoy the physical texture of this slow-growing specimen which features a very nice, layered effect. I’ve seen older specimens of ‘La Veta’ that go from being globose (rounded) to becoming a bit more upright in time once they reach about 48 inches tall. The variety ‘Compacta’ was first introduced in 1923 and is the classic favorite for an irregular mound of powder blue in the border or rock garden. Judicious pruning can be applied at any time as needed and this variety is one of the more commonly available in the nursery industry. In the “very blue” category of compact white firs, you can’t go wrong with ‘Wattezii Prostrata’ which has very large needles in a blue cast similar to the taller forms of ‘Candicans’ and ‘Blue Cloak’ mentioned earlier. I first saw this selection at the home of plant breeder Hans Hansen in southwest Michigan and it caught my eye from 100 feet away. With the bright orange of butterfly weed (Asclepias tuberosa) in close proximity, this blue and orange combination really worked well. This selection is purported to get about 2 feet tall and 6 feet wide, but it will likely continue to slowly gain additional size over time.
‘Wintergold’ turns golden-yellow in winter, ages to dark green in summer and transitions to yellow again in late fall.
Some other fun selections to look for include ‘Hosta la Vista’ which is a recent selection found at Hidden Lake Gardens that features a globose to “flattened globose” form and leans towards a blue-green hue. The selection ‘Rochester Park’ is described by the American Conifer Society (ACS) as “a slow growing, upright, tree form of white fir with dense, tidy symmetrical branching, and chartreuse-green spring growth that contrasts nicely with the older gray-blue foliage.” I’ve not seen larger forms of this, but it can be found in commerce. The selection ‘Tubby’ is another blue-green form that is globose when young and becomes broadly conical with age. Tight and uniform branching is a characteristic trademark of this form. For a different look in winter, consider the selection ‘Wintergold’ which shows a bright golden-yellow needle in the cooler winter months. This slow-growing, irregular upright selection features chartreuse spring growth that ages to a dark green in summer with the butter yellow needle transition beginning again in late fall. This selection benefits from a bit of afternoon shade.
With so many opportunities to incorporate compact and unique selections of Abies concolor in the landscape, it’s important to balance their specific needs for a “happy location” with the merits of their color and form. There are limitless opportunities for these plants in beds, borders, foundation planting schemes, rock gardens and much more as their value as “all season” contributors, coupled with their durability, makes them ideal for a wide spectrum of uses. Sourcing these selections can be challenging but consider contacting local nurseries, specialty conifer nurseries and reputable online sources for specific varieties.
Mark Dwyer was the Director of Horticulture at Rotary Botanical Gardens in Janesville, Wisconsin, for 21 years. He has degrees in landscape architecture and urban forestry and now operates a private consulting practice, Landscape Prescriptions by MD. www.landscapeprescriptionsmd.com
Full speed ahead
Features - Guest Voice // Market Outlook
Navigate potential pitfalls and don’t take your foot off the gas this year.
The damage done by the COVID-19 pandemic is real, far-reaching and yet to fully manifest for many of us. No doubt we have numerous challenges yet to face on the horizon. That said, the surge in public interest in plants and gardening products was welcomed by growers and garden centers alike in 2020. Gardening enthusiasm was a singular bright spot in a very dark landscape.
Many businesses — but not all — saw some of their biggest sales increases in years. It looks like we will potentially face another busy spring in 2021. Unfortunately, the increased demand coupled with supply chain and market volatility — not to mention labor shortages — may make it challenging for growers and retailers to meet plant demand expectations in the new year.
The biggest concerns voiced to me by my clients are how and where they will find the liners or finished plants, or larger trees and shrubs, needed to meet customer demand. Perennial plugs seem to be of particular concern. I expect the consequences of such supply squeezes to come to bear in 2021, potentially dampening the sales boost we saw in 2020. Good pre-planning, assertive marketing and overall flexibility will be required to maintain brand integrity and quality until some market stability either returns, or we all adjust to a new “normal.” The trick is to maintain your brand reputation despite potential volatility.
Transparency
My advice to clients wondering how to prepare for supply challenges is to be upfront with your customers and quickly pivot to provide available alternatives. If you know you are either not going to be able to grow and stock a particular crop — or will only have limited quantities — be transparent about it early on. Truth in advertising is going to be very important with plant supply chains strained.
Book early
If you have not been taking pre-bookings or typically only allow for buying on availability, now would be a good time to consider a pre-season booking or pre-paid order strategy. Consider creating incentives for customers to pre-book or reserve items that will be in limited supply. This is one way to help your top customers feel confident they will have what they need to keep their business flowing this spring. It will also help them adjust and plan their own marketing; and reinforce your brand loyalty.
Market alternatives
Once you have gotten the hard truths out of the way, spend extra time and effort marketing what you will have. Customers will want to quickly move on from the negative to the positives and what you can do to help them keep their business flowing as seamlessly as possible.
Pre-selling your product will also help you more quickly pivot your seasonal marketing to promote remaining available items you can offer as alternatives. This will be especially helpful to landscapers who may need to change up standard color and perennial installations and will need quick access to suggested substitutions.
Price points
Increase your prices but take care not to gouge. Supply and demand can certainly drive the market and there is no reason you should not improve your margins and profit on high-demand items. But resist the urge to go overboard on your price increases.
Trust is a key factor in maintaining your brand integrity and customer relationships. Artificially overinflated prices can backfire, hurting both your brand and the industry.
Plant and gardening consumers are already hearing the message through the media that they should expect dramatically inflated plant pricing due supply strains. On the one hand, this is not the message we want customers to latch on to, as it could keep them from diving into as many gardening projects this spring. On the other hand, we do need consumers to become emotionally comfortable with somewhat higher plant prices as many growers are long overdue for better margins.
Consider how you will address this in any consumer-facing marketing you do, or work with your retail and landscape customers to provide better marketing messages of value.
Don’t slip
Be sure to keep an eye on quality. Limited supply and high demand may have you pushing crops out the door before they are ready or up to your normal standards. You may even feel forced to purchase plants or products you feel are substandard just to meet demand. Take care not to allow your quality to slip during this time. Again, your brand integrity relies on your customers trust in consistency and quality.
Ultimately, now is not the time to take your foot off the gas, even with potential shortages. You just may have to take a few turns off your normal route to navigate what could be both a strained and successful spring season.
This article was previously written by Leslie Halleck for our sister magazine, Greenhouse Management.
About the author: Leslie (CPH) owns Halleck Horticultural, LLC, through which she provides horticultural consulting, business and marketing strategy, product development and branding, and content creation for green industry companies. lesliehalleck.com
Risks and rewards of recycling
Features - Growing Media
Reusing growing media can make your operation more eco-friendly, but don’t let your plants suffer from improper practices.
Nursery (and sometimes greenhouse/flower) operations often stockpile (A and B) overs, rejects, damaged, and unsold plants and attempt to repurpose them by (C) grinding in a tub grinder (or like device) and (D) piling or windrowing the material for some period of time before being reused in future crop production.
The demand, use and need of growing media worldwide is increasing due to the increased production of plants in containers and controlled environments. An industry that once primarily served the floriculture and ornamental nursery industries now serves a booming industry of container-grown vegetables, cannabis, herbs, leafy greens and small/soft fruit. The future is very promising and strong for the continued need of various growing media components as more and more countries become more advanced in growing crops in containers, and as more and more different (both new and traditional) crops around the world begin to be cultivated in places other than the field.
With increased demand and use comes increased interest by some to recycle or reuse their growing media, otherwise it has to be disposed of in some way. A practice that is as old as our current green industry, the reuse or repurposing of growing media has been met with rewards as well as some serious challenges by different individuals. While searching the scientific literature, trade magazines and online sources, I began to quickly realize the scope of what is known, not known or believed regarding the pros and cons of reusing growing media. The following terms occurred multiple times as I searched this topic: reduce, reuse, recycle, reutilize, rehabilitate, reclaim, repurpose, restore, regrind, recondition, replace, reduce, reprocess, repeated, reapplied. I never knew there were so many synonyms for reuse! With this being stated, let’s take a quick look at some of the various pros and cons of reusing organic growing media. The reuse of inorganic materials (rock/mineral wools, perlite, pumice, clay pebbles, etc.) deserves a separate and more thorough discussion of their own as they have potentials, reuses and issues much different than the organic materials.
First, some terminology. Often, nomenclature can often be confusing, and words or concepts are used interchangeably when they should not be.
Sterilization — the temporary destruction of most all living organisms including microorganisms, bacteria, fungi/spores, nematodes, insect eggs, weed seeds, etc. using heat of at least 212 °F for at least 30 minutes.
Sterile — free from most harmful pests or diseases commonly problematic for cultivated plants. Can be achieved without steaming/heating and does not eliminate all microorganisms/biology in the soil/substrate.
Sanitation — a condition, situation or environment that is free of harmful pests.
Solarization — the use of the sun’s energy to heat soil/growing media that is covered in a transparent polyethylene tarp and allowed to heat to at least 160 °F. This can be for a short time, 30 minutes, or over the course of weeks, depending on the setup and operation.
Pasteurization — a process of making something free from most forms of bacteria, microorganisms, diseases, weed seeds or other forms of life. This is typically achieved with steaming to a temperature of about 180 °F for 30 minutes.
Some growing operations have implemented successful substrate recycling programs that include (A) grinding rootballs followed by steam sterilization of processed substrate. The steam heated processed substrate materials (B and C) can then be aged or stored until being incorporated back into the crop production cycle.
Growing media can be essentially sterile without being sterilized or pasteurized. Peat moss for example, contains many natural beneficial microorganisms, therefore not technically sterile, but it typically contains none that are harmful to plants grown in the moss. Sterilizing peat moss would destroy the beneficial organisms, thereby reducing the quality of the peat. Also, by virtue of where peat originates, it is not prone to have weed seeds or contain insect eggs/larvae, or other potential pests that would harm horticultural crops. The same can be said of many of the commercialized wood fiber products currently on the market.
Many growers may not have the need to dispose of or recycle growing media if all their crops are container-grown and shipped out or sold. An exception may be the need to dispose of unsold, damaged or poor-quality plants that often get piled outside somewhere on the property. These “death piles” can be seen at many nurseries and greenhouse grower operations across the country.
It is also important to note that even if recycled growing media (or soils) are sterilized to remove all potential pests, it does not mean that the materials will remain sterilized. Sterilization of any material is only a temporary state or condition. If pests or diseases are present in the potting or production area, they will be re-inoculated quickly.
Potential risks
Recycled growing media can have some detrimental properties that should be considered and monitored. First is the potential loss of physical properties of reused media. Over time, organic particles naturally break down (decompose), thereby decreasing structure and air porosity. If materials are ground up or otherwise handled during sterilization processes, the particle size will continue to reduce, therefore changing the physical properties when repotted. Blending in some percentage of new growing media with the old/reused would likely help with this problem.
A common practice of in ground (mineral) soil cropping systems involves the solarization of soil planting beds, common for cut flower production, when (A) fallow soil (after a crop production cycle) is covered with (B) transparent polyethelene tarps and allowed to heat via the sun until sterile. Soil carts (C and D) are also often used for loose-fill soil and soilless substrates prior to use, or reuse in crop production.
Secondly, reused growing media can house potentially harmful pathogens, pests and other unwanted goodies if not properly sterilized or treated. The infection or exposure that improperly recycled materials can have on a grower operation can be very detrimental to future crops and cropping cycles. Recycled materials left outdoors can easily be contaminated with weed seeds and or pathogens. Recycled materials not properly sterilized could contain Pythium, Fusarium, Phytophthora and other plant-sensitive diseases. The recent increase in legalized cannabis production has also exposed new biological concerns (many may be unfounded) including the presence of E. coli and Salmonella in growing media that are now being monitored and, in some cases, regulated for.
Lastly, there can be some toxicity effects from reused growing media. Mostly in the form of residual fertilizer salts that can create high EC in mixes when re-blended or reused in future crop productions. This can alter fertility practices and management as well as crop growth response and control. Desalinization via washing or flushing with hot water is needed to remove potential salts from materials like coco coir.
Potential rewards
If done properly and monitored, the reuse and recycling of growing media can save money for some growers if they are willing to invest the time and resources to properly do it. Growing media is often not cheap, so it is possible to save some money. Reuse of materials is also a great way to reduce the disposal of organic and inorganic materials and make operations more sustainable and carbon-neutral. Some cut flower growers and others have the process of recycling their growing media down to a science and have been very successful for many years incorporating it into their growing systems.
Recycled organic substrate materials stored outdoors can often contain weed seeds (and pathogens) if not aged properly.
Your growing media is such a vital part of the success of your production system, be that large or small, professional or hobby market. If you reuse or recycle, do it right and understand the potential consequences. Cutting corners or trying to save a dollar may be worth it on some things, but do not jeopardize the quality and performance of your growing media. Your plants will thank you.
The author is an associate professor and director of the Horticultural Substrates Laboratory at North Carolina State University. He can be reached at Brian_Jackson@ncsu.edu