This summer, Gateway Greening Educators Meg Holmes and Lucy Herleth had the opportunity to be a part of the Nahed Chapman New American Academy garden’s story by participating in summer school.
Meet the International Welcome School Garden
“My original question was…Can we provide refugee students with information that can assist them in overcoming the unique challenges that exist in their classrooms? As the nation’s demographics change, so does our responsibility to meet the needs of this diverse student body. These students have significant implications for educational and social policy. One component of the Nahed Chapman New American Academy ecological milieu was to provide avenues for in-depth discussions of practices that can help all students make informed choices when it comes to our environment. As a result of those discussions, surveys were taken and students decided to plan and grow an International Garden.” – Nelver Brooks, educator and garden leader at the Nahed Chapman New American Academy
Read the rest of Nelver Brooks original story of the International Garden’s founding:The Journey Begins with Us, on the Gateway Greening Blog.
“The first week of summer school, many students visited the school garden for the very first time. They looked around for different parts of plants and noticed how plants changed as they grew. They inspected and planted tiny seeds, crouched down and counted the small seedlings, and looked around for flowers. The best part was when they discovered that the bean plants were ready to harvest. The students picked long green beans and I showed them how to carefully open the pods. Inside of the bean was a surprise – seeds! The plant’s growth was a life cycle, going from seed to seed. The kids then tasted the raw beans or fed them to the worms in the compost bin.” -Lucy Herleth
Summer School in the International Welcome School Garden
During the final week of Summer School, we caught up with Meg as she led the students through an exploration of compost and the process of decomposition.
Meg kicked off each class’s time in the garden with story time beneath the shady trees that line the school’s courtyard. Compost Stew, and A to Z Recipe for the Earth by Mary McKenna Siddals is a “rhyming recipe [that] explains how to make the dark, crumbly, rich, earth-friendly food called compost,” and is a fun way to engage students in a conversation about the compost bins in the International Welcome School Garden.
After the story, students were invited to share what they had learned, and what they might already know about composting from their home country. Moments like these are a chance to connect concepts and new vocabulary words to hands-on activities. As Meg says, “Outdoor experiential learning [is important] so that when they’re in the classroom, they have scaffolding to hang their experiences on.”
Curious about the lessons Gateway Greening Educators use in school gardens? Check out our Seed to STEM program on the Gateway Greening website to learn more!
Things took a laughter-filled turn as students insisted on taking a detour to the planting beds to check on their crops. This summer, the garden is overflowing with okra, corn, cucumbers, sweet potatoes, hot peppers, eggplants, tomatoes, beans, and even wildflowers for the pollinators – all planted by the students. The detour was full of small moments of joy as students discovered new peppers or tomatoes hiding among the leaves.
Joy has been a regular guest in the International School Garden this summer:
“After learning how plants need food, water, air, and space to grow, the students enthusiastically weeded the corn garden bed. The soil was hard, so it was a struggle to get many of the weeds out by their roots. With each weed, almost every student wanted to show the teachers the plant, waving the weed proudly around. Students even discovered that some weeds at their school looked similar to weeds back in their home country.” – Lucy Herleth
Composting at School
In 2016, the International Welcome School Garden was awarded a three-bin compost system through Gateway Greening’s Garden expansion program. Designed to be easy for people of all sizes and ages to use, the compost bins are perfect for jumping in and exploring during class! Meg made the most of the students’ ‘summer energy’ with a hands-on crash course on how the compost system works.
One of the many challenges faced by urban gardeners is the constant presence of trash blowing around and the International School sees its fair share blow into the courtyard. During the lesson, Meg had each class picking up debris and deciding whether it belonged in the trash, the recycling, or the compost pile. Within no time at all the students had the garden tidied up and moved on to the next project, but the lesson they learned will continue when they return to the garden this fall.
No lesson on composting could be complete without an introduction to some of our favorite decomposers – worms!
“Vermicomposting systems are easy to set up in the classroom and are a great jumping off point for lessons on energy use, decomposition, habitat, and more.” – Lucy Herleth
Many of the Academy’s students had never encountered the strange looking, wriggling creatures that are worms before and spent several minutes squealing as their peers bravely agreed to hold them. However, after a few minutes of talking about what worms are and explaining how hard they work to make the garden a healthier, more productive space, many of the students began to calm down and ask if they could hold a worm too.
Encountering new creatures, learning what they eat and how they live, can be an opportunity for each of the students to practice empathy and other social/emotional skills that are an important part of every child’s development.
Summer school in the International Welcome Garden may have ended for the year, but the lessons will continue this fall when classes resume.
“Not having worked with ESL (English as a Second Language) students before, and always when you have new kids, you are a little apprehensive, but food is a great way to bring people together and it’s a great way to find common ground with anyone.” – Meg Holmes
Over the years, many people have expressed their concern over Gateway Greening’s decision to use treated lumber for gardening purposes. Today, we would like to take a moment to address those concerns and to provide information on the different types of treated lumber available in general and the materials Gateway Greening uses in particular.
What is Treated Lumber?
Treated lumber is wood that has had compounds added to it in order to prevent wood-decaying organisms (bacteria, fungus, and insects) from decomposing the wood (1). Treated lumber is typically “pressure treated,” meaning high pressures are used to force preservative compounds into the wood. This provides more protection long term than a simple surface coat would.
Unlike untreated lumber, which will quickly start to break down when left exposed to the elements and wood-decaying organisms, treated wood remains usable for many years (1).
The History – CCA Lumber Treatment
Throughout much of the 20th century, lumber companies relied on a lumber treatment that utilized Chromium, Copper, and Arsenic (CCA). Studies found that arsenic could be leaching into soils that came into contact with the CCA treated lumber. However, arsenic is a compound found naturally in soils and the leaching was considered to be within safe limits.
Although CCA treatments were not found to pose an “unreasonable risk to the public” (2), the EPA decided to reduce Arsenic exposure, (3) (2) leading companies to cease manufacturing CCA lumber for residential use (4) in December of 2003.
After the 2003 EPA decision1, horticulturally focused authors and agriculture enthusiasts began to warn gardeners of the risk of using CCA treated lumber for gardening purposes.Similarly, Gateway Greening does not use CCA treated lumber for its gardens, urban farm, or other civic greening projects.
Lumber after CCA
In the aftermath of the 2003 EPA decision1, the lumber industry developed several alternative treatments which provided the same level of decay resistance as CCA treated lumber, without using arsenic or chromium.
Gateway Greening uses the Lifewood brand of lumber which is treated with micronized copper azole. According to the Missouri Department of Agriculture and the USDA’s Forest Products Laboratory, Lifewood’s copper azole treatment “is comprised of 96-percent copper and 4- percent tebuconazole,” a fungicide (5) (6).
The Lifewood brand was the first lumber treatment brand to be certified by the Scientific Certification System (SCS) as an “Environmentally Preferable Product,” meaning that it meets qualifications for this environmental certification based on an independent life cycle assessment (7). (The qualifications to receive this certification can be explored on the SCS’s website (8)). Products that receive Environmentally Preferable Product certification have been independently assessed to verify that the product is better for the environment than the prevailing, similar products (8)). Products that receive Environmentally Preferable Product certification have been independently assessed to verify that the product is better for the environment than the prevailing, similar products.
The copper azole lumber treatment is considered to be a safe choice for raised vegetable beds. University of Missouri Extension states that copper azole is as safe for raised beds as a similar type of wood treatment, known as ACQ, and confirms, “exposure to copper from contact with ACQ-treated wood is not expected to have adverse effects on the health of adults or children” (9).
While it is a known fact that some amount of copper and the fungicide tebuconazole will leach from the lumber into the soil over time, this happens at such low levels it is not considered dangerous. In fact, copper azole treated wood is actually suggested by Iowa State University Extension for use in raised vegetable beds (10).
The use of Copper in Lumber Treatments
Copper is a common component of treated lumber because of copper’s antifungal properties (2)(9). Copper’s antifungal nature helps to prevent fungus from colonizing and decomposing wood, allowing treated lumber to last longer than untreated lumber.
Although there is a fair amount of copper in Lifewood brand lumber, the life cycle assessment of the product states,
Wood products treated with the Osmose MicroPro process result in the release of 90% to 99% less copper into aquatic and terrestrial environments when compared to standard treated wood products. The very small amount released bonds readily to organic matter in the soil and becomes biologically inactive, thus effectively eliminating eco-toxic impacts (11).
In short, although there is more copper in the copper azole lumber it actually leaches less copper into soil than the CCA treated lumber over time. The small amounts of copper that do leach are soon trapped in the soil, meaning it cannot be taken up by vegetable plants.
Researchers at Pennsylvania State University have also studied copper leaching while studying CCA treated lumber for use in gardening, and discuss some of their findings in a publication. When discussing potential leaching of arsenic (As), chromium, (Cr) and copper (Cu) from the old CCA lumber, the researchers found that:
When trace elements such as these three are added to soil, most of what is added is not available for plant uptake. Chromium and copper are bound very strongly by soil particles, especially by soil clays and organic matter. They are most strongly bound in near-neutral soils (pH 6–8) and become more soluble in acidic soils (pH less than 5). As a result, Cr and Cu tend not to move in soil, and only a small fraction of what is added to the soil can be taken up by plants (2).
The publication later emphasizes this by stating that gardeners can avoid potential plant uptake of these nutrients by “Maintain(ing) soil pH in the near-neutral range (pH 6–7). Solubility of Cr and Cu is greatly reduced in neutral soils,” and, “Maintain high soil organic matter levels by adding compost or manure. Organic matter strongly binds As, Cr, and Cu and thus reduces their availability to plants,” two things that gardeners typically do as part of their regular gardening efforts (2). Even if some copper is absorbed by plants, Pennsylvania State University states that:
…the human body can tolerate relatively large intakes of Cr and Cu and is also able to excrete excess amounts of these metals. Furthermore, plants are less tolerant of Cr and Cu than humans are. This means that Cr and Cu would kill plants before plant tissue concentrations could get high enough to cause a chronic toxic effect in humans from eating the plants (2).
In summary, research shows that although the copper azole treatment is 96% copper and is known to leach into the surrounding soil:
Leached copper is quickly bound up in clay and organic matter so that it is highly unlikely that garden plants would absorb it.
Copper is far more toxic to plants than humans, meaning that garden plants would die before carrying harmful levels of copper to the dinner table.
Copper is actually an essential nutrient for humans, and our bodies are able to absorb the needed amount, then safely pass any excess.
The use of Fungicide in Lumber Treatments
Like copper, the fungicide tebuconazole is added to copper azole treated lumber in order to prevent fungus from rotting away lumber. More specifically, the fungicide is needed to control certain wood-rotting fungus that copper cannot kill (12).
According to a study done for the European Union, “An accumulation of tebuconazole in soil is not anticipated when tebuconazole is used as a wood preservative” (13). It further states that, “Tebuconazole has a low mobility potential” (13) meaning that the fungicide is unlikely to leach from the treated lumber and into the surrounding garden soil to any significant degree.
Two different studies where tebuconazole was sprayed on the soil surface found that it was readily locked up by the soil during experiments, with most of it staying within 2” of the surface (14). Further research revealed that tebuconazole’s mobility in an agricultural field (as opposed to a controlled laboratory setting) is similarly immobile, though when organic matter is added it becomes more mobile in the soil with most of it remaining within 1-4 inches of the soil surface (15). However, the organic matter also speeds up tebuconazole’s decomposition in the soil so that it has a half-life of only 8-12 days when soil has added organic matter (15).
Although these results are not a perfect analogy because the studies relied on applying tebuconazole directly to the surface of the soil rather than being bound to wood, they do provide a fairly accurate idea of the movement and leaching capabilities of the tebuconazole fungicide used in treated lumber.
Lumber used by Gateway Greening
The treated lumber Gateway Greening uses to build raised beds is only treated with copper and a fungicide tebuconazole. This type of treated lumber results in far less leaching than alternative lumber treatments. The components that do leach are mostly locked up by clay and organic matter in soil meaning it is harder for the plant to absorb it.
Copper becomes even harder for plants to absorb when the soil is a neutral pH, a goal most St. Louis gardeners strive for in order to grow the best possible vegetables.
It is also harder for plants to absorb copper if organic matter (compost) is added, which gardeners in the St. Louis region typically do in order to promote healthy vegetable production.
If a plant does absorb copper, the plant would die before it could absorb enough to be dangerous for human consumption. Even if someone were to eat a plant that has absorbed copper, and the copper had moved into the edible parts of the plant, the human body is adapted to get rid of excess copper – an essential element in the human diet.
Lumber treated with tebuconazole is not expected to release worrisome amounts of the fungicide into the soil given that it is found in the wood and in the soil immediately next to it only. Even when the fungicide was sprayed on the soil surface during testing trials, most of the fungicide only moved 1-4” down when soil was properly amended. However, amendments sped up the breakdown of the fungicide.
Why not use Untreated Wood or Cedar?
Many ask about “natural” alternatives to treated wood, or ask why we do not just use untreated wood or naturally rot-resistant wood like cedar. While we technically could use “natural” alternatives, there are several key reasons why Gateway Greening recommends the treated option instead.
The main reason we do not use untreated lumber is because the most readily available untreated lumber is pine, which is a softwood and rots very quickly. Researchers at the University of Georgia report that, “pine has almost no resistance to rot or insects and has a very short life when used in direct contact with soil” (16).
Untreated hardwoods like oak are more rot-resistant but have their own drawbacks. Firstly, only the heartwood of lumber is resistant to rot, with the sapwood of even rot-resistant species being just as susceptible to rot as the sapwood of the more rot-prone softwoods (1). So for woods like oak to be longer lasting than pine you need to make sure you are buying lumber that doesn’t contain sapwood. It is also generally difficult to find those harder woods in sizes good for raised beds and they are significantly more expensive than treated pine, and “based on most research, provide only slightly more rot and insect resistance than pine” (16).
By far the favorite wood material for those trying to avoid all treatment processes is western red cedar. Although cedar is a great wood if you are trying to avoid all treatment it is still not ideal for Gateway Greening’s school and community garden programs. The biggest reason is cost. Cedar boards usually cost four to five times more than treated pine. This much greater cost would reduce the number of gardens Gateway Greening currently serves by 75%.
In addition to the upfront cost, despite cedar’s rot-resistant nature, it still has a shorter lifespan than treated lumber when in contact with soil (17). Researchers at the University of Georgia report that fence posts made of treated pine can last up to twice as long as western cedar. Even comparing the best case for cedar to the worst case for treated lumber, the treated lumber still lasts longer (17). Although a fence post isn’t exactly the same as a raised bed it does give a good idea of how the different woods will respond to being in constant contact with soil and regional weather conditions.
We hope that we have been able to address and alleviate many of the concerns gardeners often voice at the use of treated lumber in local community garden projects. If not, please do not hesitate to reach out to our staff to ask questions!
Dig It STL is Gateway Greening’s teen employment program where teens work for eight weeks on building knowledge about urban agriculture, food access issues, and community leadership.
On Dig It STL’s first day the team played a game where they had to name another team member when a blue tarp was lowered between them. The team, initially shy, warmed up as they raced to shout an opponent’s name as soon as their head peeked over the tarp. While the game is fun and spontaneous, it also serves a vital purpose in helping the crew begin to feel comfortable with each other.
The teens come into the program unfamiliar with each other and with a variety of interests. Some teens come into the program passionate about the environment and wanting to save the world. Others are interested in plants and growing food. And many want to learn public speaking and leadership skills.
In the Dig It STL program, the teens learn about all of these things and more. During the first week of the program the crew created a community contract. This contract details the ways they will treat each other and themselves. They also did a variety of icebreakers and team building activities so that the crew can begin to bond.
The program includes frequent workshops that focus on environmental, interpersonal, and farming skills. They range from Soils 101 to learning how to give a great elevator speech.
“My favorite part is the workshops because you get to see environmental science concepts applied to agriculture,” said Joe, a Dig It STL crew leader.
The teens also receive feedback from staff and other fellow crew members during an exercise they call “straight talk.” During straight talk, the teens also cultivate emotional intelligence by reflecting on their own progress and goals.
But it’s not all workshops and team building for the Dig It STL teens. They also take field trips to local farms, gardens and organizations. Joe says that he is particularly excited to visit Flower Hills Farm, a sustainable and organic flower farm. The field trips are designed for teens to learn more about sustainable agriculture. They also get to see the variety of opportunities available to them in the field.
However, most of the work that the teens do revolves around keeping the Gateway Greening Urban Farm running. They do a lot of weeding, watering, and harvesting, as well as learning the practices required to keep an urban farm running. These practices include irrigation, natural pest control, and crop rotation.
All of this knowledge will aid the crew as they perform their final project as Dig It STL members, a teen led harvest. This will be the first year that the program will culminate in a teen led harvest. This will ensure that the teens both understand sustainable agriculture practices and have gained leadership skills through the program.
“The harvest will allow the teens to use the leadership skills they’ve gained, as well as use their knowledge about agriculture in a self-directed way,” said Carolyn, teen programs coordinator.
Ultimately though, building a loving community in which the teens can learn to both respect others and themselves is the goal of the program. Building community is vital in creating a city where people can collaborate to eliminate hunger and inequality. Within a loving community, it is possible to address these large issues because people are committed to the mission and each other, regardless of individual differences that could otherwise cause division and fragmentation.
Though not all of the teens will become best friends, that’s not the point. Fostering redeeming goodwill for all does not require friendship or affection, just commitment to improving the city and community one lives in. And solving issues like hunger requires such a commitment. Food and the natural world create connection.
And no one says that better than Alana, a crew leader of Dig It STL.
“When you bring people together in the outdoors, they bond.”
We added a high school internship program to Dig It StL, read more here: