Article adapted from The scientific reasons you should resolve to start gardening in 2023, first published by Lisa Marshall at CU Boulder Today
Anyone who has gardened can tell you that gardening has a powerful effect on both mind and body, and we’re excited to share new research confirming those outcomes!
DUG was honored to be a partner in a 3-year (2018-2020) randomized trial exploring the physical and mental health benefits of community gardening funded by American Cancer Society and conducted by researchers from University of Colorado Boulder, Colorado State University, University of North Carolina at Chapel Hill, Michigan State University, University of Colorado Anschutz Medical Campus, University of South Carolina, and Urban Institute.
The study, operated exclusively in DUG gardens, found that people who started gardening ate more fiber and got more physical activity—two known ways to reduce risk of cancer and chronic diseases. They also saw their levels of stress and anxiety significantly decrease.
Professor Jill Litt (right) checks on a plant with colleague Erin Decker (left) at a community garden next to Regis University. Photos by Glenn Asakawa/CU Boulder, 2017.
Filling the research gap
Some small observational studies have found that people who garden tend to eat more fruits and vegetables and have a healthier weight. But it has been unclear whether healthier people just tend to garden, or gardening influences health.
Only three studies have applied the gold standard of scientific research, the randomized controlled trial, to the pastime. None have looked specifically at community gardening.
To fill the gap, senior author Jill Litt, a professor in the Department of Environmental Studies at CU Boulder, recruited 291 non-gardening adults, average age of 41, from the Denver area. More than a third were Hispanic and more than half came from low-income households.
After the last spring frost, half were assigned to the community gardening group and half to a control group that was asked to wait one year to start gardening.
The gardening group received a free community garden plot, some seeds and seedlings, and an introductory gardening course through the nonprofit Denver Urban Gardens program and a study partner.
Both groups took periodic surveys about their nutritional intake and mental health, underwent body measurements and wore activity monitors.
By fall, those in the gardening group were eating, on average, 1.4 grams more fiber per day than the control group—an increase of about 7%.
The authors note that fiber exerts a profound effect on inflammatory and immune responses, influencing everything from how we metabolize food to how healthy our gut microbiome is to how susceptible we are to diabetes and certain cancers.
While doctors recommend about 25 to 38 grams of fiber per day, the average adult consumes less than 16 grams.
“An increase of one gram of fiber can have large, positive effects on health,” said co-author James Hebert, director of University of South Carolina’s cancer prevention and control program.
The gardening group also increased their physical activity levels by about 42 minutes per week. Public health agencies recommend at least 150 minutes of physical activity per week, a recommendation only a quarter of the U.S. population meets. With just two to three visits to the community garden weekly, participants met 28% of that requirement.
Study participants also saw their stress and anxiety levels decrease, with those who came into the study most stressed and anxious seeing the greatest reduction in mental health issues.
The study also confirmed that even novice gardeners can reap measurable health benefits of the pastime in their first season. As they have more experience and enjoy greater yields, Litt suspects such benefits will increase.
The study results don’t surprise Linda Appel Lipsius, executive director of Denver Urban Gardens (DUG). “It’s transformational, even life-saving, for so many people,” Lipsius said.
Many DUG participants live in areas where access to affordable fresh fruits and vegetables is otherwise extremely limited. Some are low-income immigrants now living in apartments—having a garden plot allows them to grow food from their home country and pass on traditional recipes to their family and neighbors.
The social connection is also huge.
“Even if you come to the garden looking to grow your food on your own in a quiet place, you start to look at your neighbor’s plot and share techniques and recipes, and over time relationships bloom,” said Litt, noting that while gardening alone is good for you, gardening in community may have additional benefits. “It’s not just about the fruits and vegetables. It’s also about being in a natural space outdoors together with others.”
On December 18th 2022, the DUG community and Denver suffered a terrible and unexpected loss when Ainslie O’Neil was struck by a car while biking and died of her injuries at the age of 32.
Ainslie was a landscape architect, designer, educator, and gardener. She was passionately devoted to creating a better urban future in the city of her birth–physically, socially, economically, and culturally. She was a part of the teaching team for the Denver Permaculture Design Course for ten years and was recently working with DUG in multiple capacities: re-designing a garden with her landscape architecture skills and as a member of the Therapeutic Garden Initiative task force. She was honest, brave, focused, energetic, and endlessly positive in all her endeavors.
Ainslie was a committed bike commuter, sometimes arriving at classes or meetings after riding for an hour or more. Her death at the hands of a car, while biking along a dedicated bikeway, is a particular wrench of the knife for those of us who knew her.
While the city is continuing to allocate more money for bike lanes and biker safety, we still undeniably live in a car culture, with all the speed, violence, and chaos that can bring.
Ainslie loved her family, her friends, her dog, and her garden. She loved the mountains, a long hike, and a good soak in a hot tub. She loved collaborating with others to create space for radical change, and exposing students to new ways of seeing the world. Her memorial at the Posner Center was a testament to her impact, as people from all walks of life and all parts of the city and beyond packed in to celebrate a life well lived.
Here within the DUG staff, Ainslie had many friends, and her passing has shocked and stunned us. Of course death begets life, and every day is an opportunity to weave elements of Ainslie into our what we do: a deep care for people and the land, a tireless motivation to do good work, and a recognition that taking time in the garden is one of the best ways to care for ourselves, finding peace and belonging wherever we are. May she lead us on.
Donations to DUG are being matched $ for $ through the end of the year!
As we approach the end of year, we’re not talking about the problems we’re facing–we’re focused on how we can work together to make things better.
For us, it starts with hope.
That it’s still possible for the world to be a sustainable place for generations to come, that we can grow and nurture our common ground, that we can heal ourselves and the soil while building regenerative local food systems.
2022 has been a monumental year of growth for us as an organization and we’re looking forward to digging in deeper next year. From planting new food forests throughout the city and providing critical resources to gardens through our Baseline Infrastructure Initiative to deepening gardening skills for people of all ages and providing opportunities for community and home gardeners to connect and learn from each other, we’ve got our hands in the soil and our eyes focused our vision of a sustainable urban future where people are deeply and directly connected to the earth, each other, and the food they eat.
We believe that by growing in community, we’re strengthening our ability to access healthy food, live in harmony with the earth and each other, and be more resilient. Join our growing movement to spread seeds of hope across metro Denver.
A better world is not only possible, we’re ensuring it is coming.
When you give to DUG, you’re investing in a sustainable urban future where people are deeply and directly connected to the earth, each other, and the food they eat.
Plus, through the end of 2022, every dollar you give is DOUBLED through our match–just one more big reason to give!
This fall, our bilingual youth educators Laura Calderon and Paula Thomas have been leading a K-2 Garden Club called Semillitas (little seeds) at Valdez Elementary in Denver’s northside.
The club is dedicated to welcoming kids into the garden space and planting the seed of gardening in their minds as a vital part of their lives. Research has shown that kids who get exposed to gardening go on to eat more fruits and veggies!
Following a learning-by-playing model, Semillitas Garden Club is a place for children to explore the world of gardening, from seed to flower. The kids are exposed to gardening books, arts and crafts, and direct hands-in-the-soil gardening. Through guiding questions, our instructors connect kids with key concepts like soil composition, parts of the plant, ecosystems, and more.
Garden Club Guidelines
1- Respect all living things
2- Move carefully in the garden
3- Pick only with permission
4- Use tools carefully and return them when finished
Objectives and Outcomes:
To introduce kids to the garden, the practice of gardening, and the many creatures that form a garden ecosystem
To grow future garden lovers in the different communities
To spark curiosity about the natural world
To instill joy in tending a garden
To connect children to healthy foods – from garden to plate
Earlier this year we shared about our new Food Forest Initiative, seeded with support from The Giving Grove, a national nonprofit serving communities experiencing food insecurity. We are now thrilled to share that DUG has received a transformational gift from the Etkin Family Foundation to expand our work to
20 food forests across metro Denver in 2023!
This year, DUG has finished planting the first six food forests– oases of perennial fruits, nuts, and berries– that will produce food for decades and become neighborhood fixtures. These sites will also serve as learning labs for experimentation with other perennial edibles and medicinal plants and are being set up as educational zones with permanent signage to help people learn to identify, care for, and harvest trees and perennial foods.
In total, and with the support of many fabulous volunteer groups, we have have already planted 113 trees, more than 120 companion plants, and 116 berry bushes at 6 sites located across Denver.
We are now deep in the planning process for 2023 and are looking for at least 10 additional sites that would fertile ground for a new garden! If you think you know of a site located on public or private land that may be available, we are looking for:
- Water Access – Existing water infrastructure that we can tap into. This could be garden irrigation lines, or a building (school/church/etc.) that we can extend a new line from. DUG will cover the cost of the new irrigation infrastructure.
- 2,000 Square Feet – This is the absolute minimum for sites to be able to plant at least 10 trees and companion plants at each.
- Carbon Sequestration Potential – Should not be an area that already has trees or a healthy ecosystem.
Ideal To Have
- 3,000 – 6,000 Square Feet – Even if we don’t plant everything out in the first year, a site with room for 20 or more trees is excellent.
- Volunteer Stewards – Preference may be given to sites that already have one or more people ready to be Tree Keepers and be the main steward of the site. (See below for Tree Keeper requirements.)
- North or East Aspect – Areas that stay cool for longer are the best for fruiting trees here. Maybe the north or east side of a building, wall, fence, or slope.
- Marginal Area – We want places that aren’t good for garden expansion or other more intensive uses. Slopes, strips, or overwatered and unused grass are great places to start.
- Easy Access – Spots where we can drop mulch and bring in trucks easily will facilitate workdays
- Fencing – Unless they’re inside a garden, these spaces do NOT need to have pre-existing fencing, and in most cases we will plan to keep them unfenced.
- Good Soil – It will help the trees get established, but we’re also engaged in work that will remediate and improve soil, so we don’t need the cushiest spots.
- Pathways – A blank slate is fine
DUG ‘food forests’ are being cared for by volunteer “Tree Keepers,” who receive discounted supplies, digital trainings, lots of planning resources, as well as demographic data on neighborhoods served from
our partners at The Giving Grove.
Each food forest has at least two Tree Keepers who will shepherd and steward the site.
It will be their perennial playground, where they can make changes as needed–but it will also be their responsibility to ensure the survival and establishment of the trees and plants.
Commitment and Expectations for Tree Keepers
- At least two-year commitment: we want this to become something you own, love, and care for for a long time to come, and the less turnover the better. This is not just a place where you take orders from us at DUG, but something that reflects you and your passions and skills.
- 30-60 minutes of work per week on average: there will be less to do through the winter, a lot more to do during pruning season, and you will be expected to keep close tabs on the site at all times so you can see disease and pest issues as they arise. The most consistent and crucial work is watering for tree establishment.
- Work collaboratively with at least one other Tree Keeper to meet goals. This will be someone outside of your family, although you are more than welcome to involve partners, family, and friends in this work.
- If you ever need to transition away from being a Tree Keeper, we ask that you recruit and find your replacement.
Support, Training, and Materials from DUG
- A bucket of materials: orcharding book, pruners, pruning saw, tie tape, limb spreaders, hat, and t-shirt. These are yours to keep for as long as you’re a Tree Keeper with us–if you ever need to find a replacement, we ask that you transfer the pruners, saw, and book to that replacement.
- Throughout the year there will be a series of tree-care workshops, with priority and free access given to our Tree Keepers. We will also convene some potlucks and community gatherings for our growing network.
- You will get access and notice about national tree-care trainings offered by The Giving Grove.
- DUG staff will be on-call via text or email to answer questions as they come up.
- If you want to add new plants to the food forest, we will find you funding, volunteers, and schedule workdays to get that accomplished.
Mid–late summer is an excellent time to revisit the garden, review its successes and challenges and plan for fall – the season of renewal, regrowth and reimagining. Let’s look at some strategies that invite us to optimize the health and productivity of Colorado’s unique gardening season.
Tip #1 – Know When to Plant
- Denver’s first frost can occur the first week in October
- Check the maturity date (days to harvest) on the back of seed packets
- Add the time needed for germination (usually 7 – 10 days), plus another 10 days to your time to account for slower growth with decreasing daylight hours
- Plant slightly deeper than in spring to account for hot, dry soil, moistening soil prior to planting
- Water consistently, in the cool of the day
- Always water the roots and soil, not the leaves
- Mulch planting area with straw
- Spray with liquid kelp (1 tsp. kelp concentrate per quart of water)
- Consider using shade cloth attached to a wooden frame for peas, lettuce & spinach
Tip #2 – Select Varieties Wisely
- Crops either grown for a fall harvest or planted to overwinter & mature the following spring or early summer include:
- Seeds: leaf lettuces, spinach, arugula, mustard, radish, beets, peas, carrots, kohlrabi, green onions, cilantro (may overwinter to produce early spring crop)
- Transplants: broccoli, cabbage, cauliflower, kale, brussels sprouts
- Spring, early summer harvest: garlic
- Choose the variety of seed or transplant that matures in the shortest period of time
Tip #3 – Remove Crops that are No Longer Productive
- Any spring crops still standing in the garden (peas, radish, mustards, arugula, lettuce or spinach) should be removed, chopped up & used in the compost pile if not heavily infested with insects
- Renew soil prior to planting & around established crops:
- Spread around an inch of plant–based compost (such as ‘A1 EcoGro’) on vacant plot areas & around main season crops
- Dig compost around 2” into bare areas & scratch several handfuls lightly into the soil around all remaining plants
Tip #4 – Save Space for Garlic
- Garlic is best planted in early October
- Either ‘hardneck’ (the kind that produces a flowering stalk called a ‘scape’) or ‘softneck’ (the kind usually found in grocery stores & used for garlic ‘braids’) can be planted
- Carefully separate the bulb into individual cloves, using the largest cloves for planting & smaller ones for eating
- Leave the papery skin intact & plant in compost–enriched soil, 3 – 4” deep, 4 – 5” apart in full sun
- Mulch with several inches of loose straw or chopped leaves (run over them with a lawnmower) if planting after leaf drop
- Water well several times over the winter if we don’t have adequate snow cover
Tip #5 – Plant Fall Cover Crops
- Grains such as winter rye and legumes such as hairy vetch are planted, often mixed together to cover the soil like a blanket, preventing soil erosion
- Their roots improve soil structure, opening up air channels that promote deeper rooting for subsequent crops & also provide nutrients that benefit soil microorganisms
- They can serve as habitats & food sources for beneficial insects
- They keep weed species in check by covering the soil surface & decreasing sunlight available for weed germination
- Plant by mid–late September
- Follow directions on the cover seed packet regarding amounts to plant
- Rake seed lightly into the top ¼ – ½” of soil, lightly pressing it in with a hoe
- Cover with a light layer of straw or chopped leaves
Early spring care:
- Cut down the cover crop before it reaches knee – high, leaving the top growth on the surface as a mulch & the roots in the ground.
- Wait 2 weeks for decomposition to occur prior to planting spring seeds
- Enjoy your best garden ever, knowing that you have worked to prepare fertile, moisture–retentive, biologically alive soil
Garlic likes full sun and well-drained soil. Garlic is quite tolerant when it comes to soil types and textures, but it definitely appreciates sandy-clay-loam that is friable (easily crumbled in the hand) and has a high organic content. It does best when the pH is in the 6.2 to 6.8 range. The garden or field should drain easily – standing water just won’t cut it as the bulbs could rot in the ground. To increase the tilth of the soil, add organic matter such as well-composted manure. You can also green mulch, which is planting cover crops such as clover or buckwheat and then tilling them under.
If you have a small plot, spade up the top 6 to 12 inches. Garlic roots like to go deep, so well-cultivated soil is a big help. Mix in the organic matter and manure at this phase. After the deep tilling, we find a final pass with a cultivator that powders up the upper several inches of the soil aids in planting.
When to plant? The fall is best. Remember garlic is a bulb (like tulips and daffodils). Plant 4 to 6 weeks before significant ground freezing may occur. On the High Plains, we like to get going by mid-September, since snow by the end of September is not at all that rare here. The idea is to get the cloves in the ground during warm weather so germination occurs and good root formation follows. It is good sign when you get green shoots popping above the soil in late autumn. Don’t worry. The tips may suffer a little winter burn, but they can tolerate zero and below.
When do you “crack” the bulbs? Since one obviously does not plant the bulb whole, you must crack (split) the wrapper and separate the individual cloves. It is best not to do this more than about 48 hours before actual planting, or they will begin to dry out and lose viability.
How deep to plant? We find the tips should be about 2 inches below the soil surface. For elephant (Buffalo) garlic, make that 3 to 4 inches. Be sure to plant with the pointy side up/basal plate (root) down.
How to plant? In dry climates we find it works best to let the upper few inches dry out and then bring in the cultivator. Then you can literally just stick the cloves in the ground by hand and the soil covers them up as you remove your fingers. If you have heavier and/or wetter soil, you can poke a hole in the ground with a broom handle and just drop the cloves in the hole, covering up the entire batch with a rake at the end. This works best if you water the soil several hours before planting so it is moist but not muddy.
How close do you plant them? Our experience is that closer is better. But the cloves should have enough room to grow into large bulbs (at least 4 to 6 inches for hardneck and 6-8 inches for elephants). The close planting helps with weed control once the plants get larger in spring as the leaves block out the sun to the later sprouting weeds. If you plant in rows, be sure to leave enough room (24-30 inches) in between so you can get in there to weed next spring. 24 inches wide by 21 inches long would fit approximately 20 cloves. They would be 6 inches apart going across and the rows will be 7 inches apart.
This is a key element to real garlic success. Mulch serves many purposes, not the least of which is to regulate the sharp changes in temperature and moisture that can occur during winter, especially out west. But it also goes a long way towards controlling weeds the next spring. Mulch can be straw or alfalfa. Lawn grass clippings are excellent. Chopped leaves will work if you have them. Wetting down your mulch helps compact it, making it less likely to take off. You should plan to put the mulch on immediately after planting (perhaps after giving the ground a really good watering). Don’t be shy on the mulch, at least several inches should cover your crop. You would be surprised how tough those shoots are when it comes to punching through the mulch. If you do mulch extra heavily, removing some of the overburden in spring might be a good idea, but leave enough for weed control.
Most of the time it really likes moist (not soggy) soil. Watering regularly in the fall during germination is essential. In dry climates, watering in winter is also important. Keep on watering into the spring when the maximum green shoots are forming. Then about mid- to late June, or when the scapes (on hardnecks) are standing high, STOP. During the last four weeks, when the bulbs are finishing off, and the wrappers are drying out, too much water is not good. You can create a mold or fungus problem.
When to harvest? When the lower third to half of the leaves have turned brown, but there are still mostly green leaves higher on the plant, it’s time to harvest. You can always test dig one or two plants. On the High Plains, depending on the weather, harvest can begin as early as the first week of July. There is also a two to three week difference in the harvest dates of the several varieties. To get the bulb out of the ground, don’t just try to pull them. The stalk will break. You must dig, using a pitchfork or the like in order to loosen the soil. Then you can lift the entire plant out of the ground.
CURING & STORAGE
If you want to store your garlic, you have to cure it first. After the curing process they store up to six months. The entire plant, leaves and all, should be dried out for about two to three weeks. The drier your climate the faster the curing will go and the less chance you will have to deal with mold. The simplest is to tie up a bunch with string/wire and hang them in a well ventilated place. Do not wash your bulbs or let them be exposed to water. You can also pack them loosely into large mesh bags or in open sided crates. But they must get a lot of air circulation. After the curing is complete, lop off the tops about an inch above the bulb and trim the roots.
Storing garlic requires an even temperature (50-70°F seems to work) and a relative humidity averaging in the 50-60% range. Make sure they get plenty of air circulation. Most hardneck garlics and elephants can be kept for several months. The softneck varieties do tend to have a somewhat longer shelf life.
Cover crops consist of many different types of plants, usually annual, biennial or perennial grasses or legumes, which are grown to cover the surface of the soil. After they are tilled or dug into the soil, they are known as ‘green manures’.
- Cover crops act like a blanket, preventing soil loss from wind and water erosion.
- Their roots hold the soil in place and help to improve soil structure. During the process of decomposition, microorganisms and the decomposing cover crops produce sticky substances that glue soil particles together. This opens up air channels and also increases the water holding capacity of the soil.
- Cover crops keep weed species in check by covering the soil surface and decreasing sunlight available for weed seed germination. Additionally, some grasses, such as winter rye exhibit a property know as ‘allelopathy’. Their roots, when tilled into the soil, prevent seeds from germinating until the plant has decomposed.
- Crops in the legume family, such as hairy vetch, planted with specific types of bacterial inoculants, have the ability to develop special structures on their roots that store nitrogen and make it available as the crop is dug or tilled under.
- Many cover crops reduce pest insect populations by serving as habitats and food sources for beneficial insects.
Crop and Planting Specifics
- Best choices for fall planting include Winter Rye and Hairy Vetch. Often a mix of rye and vetch is planted. Austrian winter pea is slightly less hardy.
- Plant by mid – late September as crops are harvested. Small amounts of the above varieties can be obtained from local garden centers. The mixes can also be ordered from Peaceful Valley Farm and Garden Supply: www.GrowOrganic.com
- Prepare seedbeds by digging thoroughly, adding an inch or so of decomposed compost mixed into the top 4 – 6 “ of soil. Make sure large clumps or clods are broken up.
- Water the area well prior to planting the cover crop seed.
- Follow directions on the seed package for seed sowing (Winter rye: 4 – 6 oz per 100 square feet, Hairy vetch: 2 – 3 oz per 100 square feet).
- Rake seed lightly into the top ¼ – ½” of soil, lightly pressing it in with a hoe.
- Cover with light layer of straw or chopped leaves
Early Spring Care
- Cut the rye before it reaches knee – high, then dig or till or crop remains in.
- Wait two weeks for decomposition to occur prior to planting spring seeds
- Enjoy your best garden ever, knowing that you have worked to prepare fertile, moisture-retentive, biologically alive soil.