Calling all Brownie Girl Scouts who are looking to “go green.” On Saturday, February 3, join us at Denver Botanic Gardens for our Household Elf Girl Scout Exploration Day and learn how your scout can make a positive environmental impact. </p> This Exploration Day, designed to meet the requirements of the Household Elf badge, helps Girl Scouts explore the Gardens in a whole new way as they learn how plants conserve water and energy, and how they can help the planet by conserving water and energy, too. Participating Girl Scouts also take a stylish step in reducing waste by decorating their own reusable bag, and—bonus—get their hands dirty planting an air-purifying plant! </p> Learn more about this program</a> and how you can register your Girl Scout or troop.</p> Let’s work together to make the world greener, one step at a time. </p> This article was contributed by Family and Children's Program Coordinator Helena Nitz.</strong></em></p>
Compost seems to be a hot topic these days. We all love the thick white steam cloud emitted from a healthy compost pile in the cool mornings of the fall, but what happens to a compost pile during the winter?</p> Unfortunately, most compost piles freeze solid in the coldest winter months. When a compost pile freezes, however, it isn’t lost forever. As microbes become less active, they no longer produce enough body heat to keep a pile from freezing. Just like us, soil microbes slow down in the cold. But microbes have an ability humans can only mimic in the coldest months of the year: dormancy.</p> A frozen compost pile isn’t dead; it’s dormant. In winter months, soil microbes enter a state of deep hibernation until the conditions are optimal to become active again. In some cases, ancient microbes can remain dormant for thousands of years, waiting to reemerge when a combination of oxygen, moisture and temperature form their ideal microclimate. The vast majority of compost microbes survive even the deepest freezes for a few months.</p> But what if there was a way to keep compost active in the coldest months of the year? While it is possible to keep a compost pile warm in the winter through frequent turning, snowy and icy conditions can prevent farmers and gardeners from accessing their piles. What if there was a way to keep compost warm without turning it?</p> Aerated Static Pile (ASP) composting can keep piles warm through the winter. By “forcing” air through a PVC pipe frame, ASP composting can oxygenate the center of a pile without having to turn it. While traditional compost piles should be covered with a "breathable" material, ASP systems can be sealed with a tarp. Tarps keep moisture in the pile while oxygen is introduced from outside of the pile through the forced aeration. </p> At Denver Botanic Gardens Chatfield Farms</a>, we are installing an ASP composting system this winter. While Chatfield Farms produces around 100 tons of compost a year, ASP systems are relatively easy to build at any scale. A home gardener could build an ASP system with a leaf blower and a few PVC pipes.</p> ASP composting is a great experiment to keep a “soil nerd” occupied through the offseason, but it is by no means the only way to create quality compost. So, whether your compost goes dormant during the winter or stays active year-round with an ASP system, keep up the good work!</p>
There is a debate in the garden world about the best time of year to cut back the spent foliage of herbaceous perennials and grasses. If a gardener is hoping to be sustainable, and benefit pollinators via their gardening practices, leaving debris until the spring is the best option. Spent foliage provides shelter for overwintering insects and their larva as well as seeds for birds. Plus, standing perennials provide winter interest – something beautiful to focus on in the colder months, such as dried flower stalks and attractive textures. Lastly, leaving debris in the garden provides insulation to the crowns of sensitive plants. </p> However, those who garden in Colorado know that sometimes adjustments must be made due to unpredictable weather. A particularly heavy, wet snow may flatten perennials that were still standing through the colder months. If this is the case, knock hefty loads off trees and shrubs to alleviate stress and prevent breakage to limbs. And keep an eye out for any broken branches in small and large trees near and around the garden. These “hangers” can be dangerous and will require intervention from tree-care professionals.</p> It may be tempting to get the shears out and clear cut once the snow melts. However, there may be many weeks left of wintery weather to come, and many pollinators will still require shelter. While not always the case, some plants that may seem completely smothered under the snow can rebound once it melts; just give them some time. </p> If broken stalks and smushed plants aren’t a concern, feel free to leave them be. This won’t hurt the plant; it simply has to do with aesthetics. Head out into the garden once the snow melts to do some repairs if you like but delay any heavy garden work until soil is dry to avoid compacting the soil. As for the herbaceous material on the ground, use pruners to cut broken stalks at the base of the plant and leave those that are still standing alone. Sometimes just a few cuts can be made to recreate a tidier appearance.</p> Heavy snow isn’t necessarily a bad thing for the garden. A lot of moisture and precipitation comes from those big spring snows, and plants receive a much-needed drink as it melts. And it sure is pretty. Certainly, some plants may appear damaged, but in reality, herbaceous perennials start over with fresh stalks in the growing season, so don’t fret. Unless shoveling snow from sidewalks is on the agenda...then maybe some fretting is appropriate. </p>
From sweet and floral to skunky and funky scents, the fragrance of a flower is unique. Certain floral scents are hypothesized to attract pollinators, defend against herbivores or act as a mode of communication between plants. Describing a plant as sweet or skunky is a great start, but with the right training and tools, botanists can more deeply understand the exact chemical reasons as to why a plant smells the way it does. </p> Many botanists are passionate about understanding the biochemistry responsible for plant aromatics and incorporating it into their research, like me! This past month, I took a trip to Cornell University to train with floral scent expert Robert Raguso. Using the Arkansas Valley evening-primrose (Oenothera harringtonii</em>) from the greenhouse, we practiced collecting the floral scent. To do so we needed four elements: a plant of interest, a headspace, an air pump and a method of capture. Together, these tools allow us to concentrate molecules and then move them into our method of capture to take back to the lab. If done carefully and correctly, this data collection can be done without causing any harm to the plant of interest. </p> Once back in the lab, we inject our floral scent cocktail into a machine called a gas chromatography-mass spectrometer (GC-MS), a tool which separates and breaks down samples to identify substances and determine their chemical structures and quantities. These are highly specialized instruments capable of determining even the most cryptic of compounds. After injection, the floral compounds travel through a glass column, by force of an inert gas. Inside this column, compounds are separated from one another. As the isolated compounds exit the other end of the column, they are ionized by a laser beam where their mass to charge ratio (m/z) is determined. We are left with both a chromatogram and a mass spectrum; software is then used to determine which compounds are present in our sample. </p> In the case of Oenothera harringtonii</em>, we identified several dominant compounds, particularly a compound called linalool. Linalool, an acyclic monoterpene tertiary alcohol, is known to manifest as a woody, floral scent in several notable plant genera, such as Coriandrum </em>(known for coriander and cilantro) and Lavandula </em>(known for lavender). Oenothera harringtonii </em>is a night-blooming angiosperm that requires the visitation of hawkmoths for successful pollination. Linalool is observed to attract moth visitors, while simultaneously being a deterrent of other herbivorous invertebrates. </p> Whether studying the delicate emissions of alpine wildflowers or analyzing the complex aromatics of cultivated blooms, each volatile molecule we identify tells a worthwhile chemical story. </p> Special thanks to Robert Raguso and Cornell University for taking the time to share their knowledge about floral biochemistry. Learn more about Professor Raguso’s work</a>.</p> This article was contributed by graduate student Ashlee Kerber</strong>.</em> </p>
