Your Yard is Thirsty

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When I moved to Colorado three decades ago I expected to be knee-deep in snow and cold to the bone for months on end. Little did I know, Denver winters have long dry stretches, moderate daytime temperatures and bright sunshine that melts snow before it needs to be shoveled. So much easier than the New Jersey winters of my youth. The downside is that plants often suffer from lack of moisture. This year I’m being especially diligent about winter watering to help  newly planted trees, shrubs and perennials make it through their first winter and thrive in the future. Whether nurturing young plants or insuring the longevity of established ones, here are Colorado State University’s recommendations for cold season landscape care.

  • From November to March, give plants a good drink when four weeks elapse without snow cover or adequate moisture. March is the metro area’s snowiest month (11″); January (7″) and February (6″) average the least.
  • Water when temperatures are above 40° and early enough in the day for the moisture to soak into the ground before temperatures dip below freezing.
  • Reflective heat from buildings, the lower angle of the sun and areas prone to intense wind cause root systems to dry out more quickly, watch plants in these areas closely and water accordingly.
  • Newly planted trees establish slowly – one year for every inch of trunk diameter, (measure 6″ above the soil ). A good rule of thumb is to apply 10 gallons of water per inch of trunk diameter each time you water. Water around the tree, out to the drip line and beyond. The goal is to send moisture to the tree’s entire root system at a depth of 12″. I’ve found running a sprinkler for 30 minutes does the job nicely.
  • Newly planted shrubs require more moisture than established ones (over one year old). A first year, 3′ tall shrub requires 5 gallons per watering.
  • Mulch is a plant’s friend – it helps maintain moisture and mitigate the damaging thaw/frost cycle.
  • Newly seeded lawns and perennials (especially fall planted ones) will benefit from supplemental watering if precipitation is low, too.

According to globalwarmingdenver.com, we’ve received just .02″ moisture in the last two weeks and are about 2.5″ below average precipitation year-to-date. Given our dry days and spring-like temperatures, it’s  about time to unwind the hoses.
For more information:
Planttalk Colorado: Fall & Winter Watering
Colorado State University: Fall & Winter Watering Fact Sheet 7.211

Photo credit: Pixabay.com, a source for royalty free images
Written by: Linda McDonnell, a Denver County Master Gardener

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How to Enjoy a Living Christmas Tree

When considering the price of trees these days, it makes sense to buy one that offers the biggest return on investment. That’s why I’m a big fan of living Christmas trees.

A living tree is one that makes the season bright, but also adds beauty to the landscape long after the holiday is over.

Before investing in a living Christmas tree, there are a few things to keep in mind about its care:

1. Buy a tree that fits both inside and outside the house. A smaller tree will be more manageable for moving into the house for the celebration and then outside for planting. In addition, smaller sized trees will take less time to get established in the yard after planting.

2. Select the planting site and prepare a planting hole for the tree before the ground freezes. Dig a saucer-shaped hole that’s at least three times the size of the root ball. The hole should be shallow (no deeper than the root ball) and wide. Planting too deep slows root growth and can harm the tree. Be sure to reserve the soil to fill in the hole at planting time.

3. Locate a cool spot to store the tree after getting it home. Keep it in its original container in the garage or on a sheltered porch or patio until it’s time to move it indoors.

4. Unlike a cut tree, a living Christmas tree can be indoors for just a short amount of time. Plan ahead to move the tree indoors for 5-7 days around the holiday. Then move it back to the garage.

5. Place the tree in the coolest room in the house. Avoid placing it close to the fireplace and keep it away from furnace vents that cause hot-cold temperature swings.

6. Water wisely to keep the soil moist. One easy method for watering is to put the tree’s container in a larger container, like a metal tub. Elevate the tree off the bottom of the container with a layer of gravel to keep roots away from sitting water.

7. After the holiday is over, allow time for the tree to get re-acclimated to the outdoors before planting. Place it back in the garage or cool, sheltered spot for a few days. Then take it outside and plant.

CSU Extension gives all the best practices for tree planting in the Garden Notes called The Science of Planting Trees. Be sure to remove any burlap or wire baskets before backfilling the hole and watering in the tree.

Keep your new tree watered through the winter, at least once a month or more frequently if the weather is dry and warm with a lack of snow cover.

A living Christmas tree may need a little extra TLC, but it’s one of the best ways to keep the holiday spirit alive throughout the year.

By Jodi Torpey
Denver Master Gardener since 2005

Shedding Light on Houseplants

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Daylight saving time is on hiatus, the gardening season has drawn to a close and  the long shadows of winter will soon be here.  It seems like a good time to turn our attention to the light needs of indoor plants.

Most indoor plants hail from the tropics, making their ideal growing conditions far different from what we offer in our typical homes. Thin new leaves, loss of lots of older foliage and limbs stretching towards a window can all be signs that your plant is craving more light. Without adequate light plants are unable to store energy for growth.

Indoor light is more subtle than the light in our gardens, which can make it trickier to assess. For more precision, a photographer’s light meter or a simple light meter app on your phone will measure the light in foot-candles or LUX units. Horticulturists use foot-candles, so if you have a device which gives a LUX reading, search the web for an easy LUX to foot-candle calculator.

In general, growers characterize plants as needing high, medium or low light.  Here are some guidelines to help assess the type of light in your environment with greater accuracy.

High Intensity Light

  • 1,000+ foot-candles
  • 4-6 hours of sun per day
  • Crisp shadows and dark contrast at the brightest time of day
  • Within 2’ of east facing windows
  • Within 2’ of south-facing windows (October-March)

Medium Intensity Light

  • 500+-1,000 foot-candles
  • Within 2’ of north facing windows (April-September)
  • 2-6’ from an east or west-facing window
  • 1’ to the side of an east or west-facing window
  • Approximately 10-14 hours per day of fluorescent office light

Low Intensity Light

  • 50-500 foot-candles
  • Faint shadows at the brightest time of day
  • Within 2’ of north facing windows (October-March)
  • 6-10’ from south-facing windows (April – September)
  • Few plants survive in fewer than 50 candles

Knowing the light intensity will help determine the best placement of  plants and select  plants which will thrive. Variables such as humidity, drafts and temperature also factor into a plant’s health, so be sure to take this into consideration, too.  As always, knowledge and keen observation skills are key to successful plant care.

Additional information on plants and light:

Plantalk 1352: Interior Plants and Light

Plantalk 1314: Houseplants: Artificial Light

Starting Seeds Indoors

Christmas Cactus Care (effects of light on bloom)

 

Written by Linda McDonnell, a Denver County Master Gardener

 

 

 

 

What’s In The Cauldron? The Meanings Of Plant Names

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“Fillet of a fenny snake,
In the cauldron boil and bake;
Eye of newt and toe of frog,
Wool of bat and tongue of dog,
Adder’s fork and blind-worm’s sting,
Lizard’s leg and howlet’s wing,
For a charm of powerful trouble,
Like a hell-broth boil and bubble.”

Doesn’t that just send a shiver down your spine? The immortal words of Macbeth’s witches tend to hang in the air, and you can almost hear the cauldron bubbling.
But what is that stuff in the cauldron?

Guess what? Most of it is plants!

Anyone who has worked in the garden has noticed that many plant names have odd, fanciful or gruesome names. If you really consider them, names like ‘dandelion’, ‘foxglove’ and ‘mistletoe’ are pretty odd, aren’t they?
The reason is multi-faceted. A large contributing factor is a socio-historical phenomenon known as ‘linguistic drift’, which is the term for the fact that words are changed over time. Originally, according to Oswald Cockayne’s ‘Leechdoms, Wortcunning, and Starcraft of Early England: The History of Science Before the Norman Conquest’, Dandelion was originally ‘Dent De Leon’, or ‘Lion’s Teeth’, referring to the dentition of the leaves.  Andrew Yang notes another good example in his work ‘Plant Names in Old and Middle English: Problems and Trends in Taxonomy’ : “The tan of mistletan, notes Sauer, “originally meant ‘twig,’ but it was later associated with tan [as OE] toe,” to form mistletoe.”

Another main contributing reason is pragmatic: it’s hard to forget a plant called ‘dead man’s fingers’ or ‘bear’s breeches’ as a rule, which made remembering and passing on plant knowledge much easier.

The Tryskelion Press gives us a short guide to the 16th century English plant name meanings in their August 2015 issue.

Old Name for Part Actual Part of the Herb Used
Eye Inner part of a blossom
Paw, Foot, Leg, Wing, or Toe Leaf
Guts Roots and stalk
Privates Seed
Hair Dried, stringy herbs
Tail Stem
Head Flower
Tongue Petal
Heart A bud or seed

Here’s a few examples of the common names in the 16th century and the same plants today.

Old Herbal Name Herb/Plant Name
Adder’s Fork Adder’s tongue
Adders Tongue Dogstooth Violet
Ass’s Foot or Bull’s Foot Coltsfoot
Bat Flower Tacca
Bat’s Wings Holly
Bat’s Wool Moss
Bear’s Foot Lady’s Mantle
Beggar’s Buttons Burdock
Beggar’s Tick Dianthus
Bird’s Eye Germander Speedwell
Bird’s Foot Fenugreek
Black Maidenhair Black Spleenwort
Black Sampson Echinacea
Black Snake Root Black Cohosh
Blind Eyes Poppy
Click Goosegrass
Clot Great Mullein
Corpse Candles Mullein
Corpse Plant Indian Pipe
Courtesy Summer Wind
Crocodile Dung Black Earth
Crow Corn Ague Root
Crow Foot Wild Geranium
Crowdy Kit Figwort
Crown for a King Wormwood
Cuckoo’s Bread Common Plantain
Dead Man’s Ashes Mandrake root
Death Angel Agaric
Death Flower Yarrow
Devil’s Apple Datura
Devils Dung Asafoetida
Devil’s Eye Henbane, Periwinkle
Devil’s Flower Bachelor’s Buttons
Devil’s Guts Dodder
Devil’s Milk Celandine
Devil’s Nettle Yarrow
Devil’s Oatmeal Parsley

So what was in that cauldron? Black mustard, Crowfoot, Holly, Horehound, Wormwood, and a lot of other rather powerful plants. I wouldn’t drink a cupful myself, but if you want to see visions and fly this brew would definitely do it.
Happy Halloween!

Sources

The Shakespere Standard, http://theshakespearestandard.com

Cockayne, Oswald.  Leechdoms, Wortcunning, and Starcraft of Early England: The History of Science Before the Norman Conquest, vols. 1-3.  Bristol, England: Thoemmes Press.  1864-66.

Gledhill, D.  The Names of Plants, 2nd ed.  Cambridge: 1989.

Andrew K. Yang, Plant Names in Old and Middle English: Problems and Trends in Taxonomy 

The Old English Herbarium (OEH) and Medicina de Quadrupedibus.  Hubert Jan de Vriend, ed.  Toronto: Oxford.  1984.

Tryskelion Press, Old World Names For Herbs And Plants, http://www.tryskelion.com/herbs_old_world_names_for_herbs.html

 

A Poison Plant Primer for Halloween

While on a garden tour a few years ago, I crossed over to the dark side. Instead of admiring the frilly flowering ornamental plants, I spent my time inside the Poison Plant garden. 

The gate, decorated with a large iron spider in a large iron web, creaked eerily on opening and then slammed shut behind me.

The spider signified the potential dangers that grew inside that garden, like Oleander (a glycoside). This innocent-looking plant can cause respiratory difficulties and heart problems. Although this Mediterranean shrub can be a fragrant addition to the landscape, every part of the plant is poisonous when eaten. The smoke is also toxic if plant parts are burned.

Other glycosides in the garden included foxglove and lily-of-the valley.

Why would a perfectly nice botanic garden include harmful plants among the others? For the same reason so many other plants are on display: to educate gardeners and the general public.

We can’t escape poisonous plants because they can grow anywhere. Jimson weed and nightshade; soapwort and poison ivy; stinging nettle and even St. Johnswort were a few of the other plants growing in the garden.

“A recent increase in herbal usage has given rise to misuse and mistaken identities,” explained a sign near the poison garden’s entrance. “It is important to consider means of preventing a toxic encounter as well as enjoying the contributions of poisonous plants around us.”

Because Halloween is a time for delightful frights, I recommend taking a read through Amy Stewart’s entertaining book called “Wicked Plants: The Weed that Killed Lincoln’s Mother & Other Botanical Atrocities” (Algonquin Books of Chapel Hill, 2009).

She includes poisonous plants familiar to most gardeners, like Castor Bean, Henbane, Hemlock and Deadly Nightshade. But she also includes some surprises like Habanero Chile, Sago Palm, Tobacco, Junipers and Bermuda grass.

“We assume if it grows out of the ground, a plant is natural and natural is good for you,” says Amy. But cyanide is also a natural substance that comes from some plants, and it definitely isn’t good for you.

Speaking of deadly plants, what do you think is the world’s most wicked plant? Scroll past the following poison plant resources section to learn the answer.

Resources

A nice addition to Amy’s book is a list of poison gardens throughout the world and a well-research bibliography with many poisonous plant resources and identification guides. Here are a few links to help get you started:

CSU’s Guide to Poisonous Plants database lists trees, shrubs and perennials that can be harmful to animals.

Cornell University’s College of Agriculture and Life Sciences has a searchable database of plants that are poisonous to livestock and other animals. The color images help with plant identification.

The University of Illinois Extension has a comprehensive list of links to poisonous plant information. 

The World’s Most Wicked Plant?
Tobacco

By Jodi Torpey
Denver Master Gardener since 2005

Fall in the Perennial Garden

 

McDonnell summer border 

I don’t know about you, but in my  garden, fall cleanup can be hit or miss. Whether a function of limited time, gardener burnout or an early cold spell, some years I just let it all freeze dry in place till the spring. I’ve learned to embrace the  appearance and find that doing less offers the garden many benefits, including:

  • Dried foliage will help protect the crown of perennials from the freeze/thaw cycle; this is especially good for marginally hardy perennials. If  you do prune, leave about 3-4 inches from the ground to avoid damaging the crown.
  • Dead stems “mark” the plant and lessen the chance of accidentally digging it up or stomping on it in the spring. This is really helpful for plants that “wake up” a bit late in the spring.
  • Leaves will decompose and add organic matter to the soil. They can also insulate plants from harsh winter temperatures.
  • Dropped seeds produce new plants to fill out your garden or share with others.
  • Seed heads provide tasty food for birds.
  • Some plants prefer spring pruning, such as grasses and plants with semi-woody stems like Munstead Lavender and  Wild Thing Sage or Salvia Greggii. A spring haircut when new growth emerges often yields a plant with better form and growth. (Not to mention increased chance of winter survival.)
  • Early season flowering shrubs such as lilacs have already put on the

    Photo from CSU CO Master Gardener Garden Notes

    growth that produce next year’s flowers. If you cut now, you will not have blooms next spring. These plants should be pruned shortly after blooming, or  you may have a lilac that looks like this!

Fall garden clean up does not need to be back-breaking work. Just remove diseased or mildewed foliage, lightly cut back long limbs that can be  damaged by strong winds and occasionally water if conditions are dry. Your garden will benefit from this “less is more approach”.

References:

Winterizing Perennials, Plant Talk 1020

Maintaining Perennials, Plant Talk 1019

Winterizing Perennials During Drought, Plant Talk 1064

Written by Linda McDonnell, Denver County Master Gardener. 

A version of this post was originally published in October 2015.

 

10 Reasons for Becoming a Denver Master Gardener

If you like to plant and grow things, you may be a Master Gardener in the making. A desire to help your community is another plus. In case you need more convincing, consider these 10 benefits of joining us and then take the next step to become a Colorado Master Gardener.

Number 10: You’ll be a better gardener. Becoming a Denver Master Gardener doesn’t mean you’ll be a perfect gardener, but at least you’ll know why the daisies died, what’s wrong with your tomato plant, why the lawn has brown spots, and what the heck is eating those roses. The CSU Master Gardener program is like getting a mini-degree in horticulture.

Number 9: You’ll help with important research. Master Gardeners are often called on to help with CSU Extension research projects. One recent project included collecting tree data as part of the Rollinger Tree Collection Survey project, a collaboration with the Denver Botanic Gardens and other partners to understand the past, present and future of Denver’s urban forest.

Master Gardeners like to meet, mingle and break crab legs together.

Number 8: You’ll meet and mingle with like-minded folks. Gardeners like to talk—and listen. Whether you’re a social butterfly or just like to belong to a tribe with similar interests, there are plenty of opportunities to enjoy each other’s company.

Number 7: You can share your knowledge. People have questions and now you’ll have the research-backed information to provide answers in person at farmer’s markets and special events or by answering email questions from home. There’s a lot of gardening misinformation out there, but you can help dispel the myths (except when it comes to marijuana).

Number 6: You can volunteer in meaningful ways. Community outreach is an important part of being a Denver Master Gardener and others appreciate your contribution. The vegetables grown in the Harvard Gulch Demonstration Garden are donated to help feed the hungry; The Haven at Fort Logan offers another chance to serve others with your gardening skills.

Master Gardeners plan and plant the CSU Extension exhibit at the Colorado Garden and Home Show.

Number 5: You’ll get to work behind the scenes at the Colorado Garden and Home Show. A favorite volunteer project is being part of the annual show whether helping to build the CSU Master Gardener display or answering attendee’s questions. Free entry to the show is an added bonus.

Number 4: You can stretch your leadership skills. Being a Master Gardener lets you take the lead on a special project in a safe and supportive environment. Creativity, innovation and new ideas keep the program interesting.

Number 3: You’ll receive a well-recognized credential. Anyone who’s been paying attention has heard of CSU Extension’s Master Gardener program. The title is a well-known and well respected credential in the gardening world and in every state across the country.

Number 2: You’ll be supporting an important educational program. Becoming a Master Gardener isn’t free, but the nominal annual fee ensures the Denver Master Gardener program can continue its mission.

Being a volunteer at the City Park Greenhouse refreshes gardening skills for the new season.

And the Number 1 reason for becoming a Denver Master Gardener: Volunteering at the City Park Greenhouse.  It’s one of the most revitalizing volunteer gigs, and it happens at a time of year when gardeners need it the most.

Those are my top 10 reasons. What are your top reasons for becoming a Denver Master Gardener?

By Jodi Torpey
A Denver Master Gardener since 2005

2018 Colorado Master Gardener/Colorado Gardener Applications Now Being Accepted

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We are now taking applications for the 2018 Colorado Master Gardener volunteer class. We are also recruiting Colorado Gardener Certificate students who take the classes without volunteering. The application deadline is October 18th, 2017 and weekly Wednesday classes run from January 24 through April 10, 2018 from 9:00am-4:00pm. Classes will be held at Denver Botanic Gardens and Jefferson County Fairgrounds. For more information about the program, please visit our website: http://www.cmg.colostate.edu/about.shtml

If you are interested, please call 720-913-5272 or email merrill.kingsbury@denvergov.org for an application.

If you live outside of Denver, please see this link for the CO Master Gardener Program in your county: http://www.cmg.colostate.edu/ask-cmg.shtml

Gardens in the Sky

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Denver Private Residence. Courtesy of Denver Green Roof Initiative

Green roofs or living roofs have been around for thousands of years. The Hanging Gardens of Babylon were constructed around 500 B.C. using tar and layers of reeds to waterproof structures, upon which lush plants thrived. Europeans have long embraced green roof design and today, about 10% of homes in Germany have living roofs. North America has been slower to adopt green roof design, but the practice is gaining momentum, particularly in urban areas including Chicago, New York, Portland and Washington DC. This November, Denver residents will vote on The Denver Green Roof Initiative, modeled after legislation in Vancouver, which requires commercial buildings in excess of 25,000 square feet to dedicate a portion of roof space to vegetation or solar panels.

Image courtesy of wikispaces.com

What are green roofs and why are they valuable? A green or living roof is one that is either partially or completely covered in vegetation on top of the human-made roofing structure.  There are two major types of designs – extensive and intensive. Extensive green roof systems include a thin waterproof membrane covered in a lightweight, shallow planting medium and low maintenance plants, often using a system of trays  Intensive green roofs involve a more complex system of layers, are more expensive, require greater structural support and allow for a wider range of vegetation, such as trees and shrubs (see diagram). Intensive green roofs can serve as parks or public spaces, such as the Mordecai Children’s Garden at the Denver Botanic Gardens or Highline Park, built upon an elevated historic freight line in New York City.

Anschutz Wellness Center -University of Colorado, Aurora. Courtesy of Denver Green Roof Initiative

Denver has the third highest heat island effect (the average daily urban-rural summer temperature difference over the past 10 years) in the country.  Green roofs moderate the HIE by cooling ambient air through evapotranspiration. They also provide summer and winter insulation to buildings thereby reducing the carbon footprint. Other benefits include decrease in stormwater contamination, reduction of pollution by filtering the air as it moves across the roof, additional wildlife habitat for birds, insects, spiders and other animals and absorption of noise. While green roofs, especially extensive designs, are expensive, they have been shown to last longer than traditional roofing resulting in long-term cost benefit.

 

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Denver EPA Headquarters Courtesy of Denver Green Roof Initiative

The 20,000 square foot green roof at Denver’s Environmental Protection Agency Region 8 Headquarters  was installed in 2008 in partnership with Colorado State University and other organizations. Using a system of 2′ by 4′ plastic trays, plants were studied for exposure to winter and summer extremes, wind exposure and soil conditions, among other factors. The roof contained four species of Sedums, including Sedum album (white stonecrop), Sedum kamtschaticum (Russian stonecrop), Sedum acre (goldmoss stonecrop) and Sedum spurium (two row stonecrop) and three varieties of Sedum spurium: ‘Dragon’s Blood’, ‘John Creech’ and  ‘Red Carpet”.  According to the researchers, “These plants were selected for visual appeal as well as survivability in harsh environments with temperature extremes, and for their capacity to withstand drought conditions better than most plants.” Another outstanding performer was the brittle prickly pear, Opuntia fragilis. According to Dr. Jennfer Bousselot, “It’s spectacular especially since it has been virtually untouched since the formal study ended in 2010. It has thrived on only light irrigation during the growing season.” Find extensive documentation of the project here.

 

Green roof design addresses many environmental concerns. Will it “take root” in Colorado?  To learn more about green roof design and Denver’s upcoming ballot initiative, here are some additional resources:

National Public Radio: Do Cities Need More Green Roofs?

The Denver Green Roof Initiative (includes ballot initiative)

The Denver Post, March 14, 2017. “Green roofs will benefit Denver but they shouldn’t be mandated”

 

Written by Linda McDonnell, a Denver Master Gardener

 

 

 

 

 

 

 

 

 

 

 

 

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When it Rains, Let’s Measure It

Nolan Doesken of the Colorado Climate Center at CSU demonstrates how to read a rain gauge.

Denver Master Gardeners had the chance to learn why Colorado’s climate can be so frustrating during an entertaining presentation by Nolan Doesken of CSU’s Colorado Climate Center.

The July program was one half continuing education on the basics of our state’s climate and one half recruiting effort for more rain gauge volunteers. Both halves are important to anyone who’s affected by Colorado’s crazy weather.

Doesken is the state climatologist and the founder of CoCoRaHS, the Community Collaborative Rain, Hail and Snow Network. What started as a small volunteer effort in 1998 to track and map precipitation in northern Colorado has expanded to include thousands of volunteers in all 50 states, Canada and the Bahamas.

CoCoRaHS volunteers measure and report the amount of precipitation that falls in their yards. The combined data gives a comprehensive precipitation picture that’s important to natural resource education and research.

Colorado’s early weather reports were sent by telegraph from the top of Pikes Peak beginning in 1873.

Colorado started tracking climate data in the 1870s, but that data was collected only at weather stations. Some of the first official weather measurements were on wind pressure, speed and direction.

But there’s an ongoing need for data that helps tell the weather story in more detail. The combination of Colorado’s high elevation, mid-latitude location, complex mountain topography plus our location far from the continent’s moisture sources make for a challenging climate, Doesken explained.

We can also blame those confounding 40-degree temperature swings from one day to the next on those factors, too.

Anyone who has an interest in being a citizen scientist or learning more about the weather is invited to join the CoCoRaHS network. Volunteers use high-capacity rain gauges placed wherever rain can land without interruption.

Because precipitation can vary from neighborhood to neighborhood, volunteers are needed in all areas. Each time it rains, hails or snows, volunteers measure the amount of precipitation and report it on the program’s website.

The rainfall reports get used every single day, Doesken said. Even 0″ precipitation reports are important. Data users include weather forecasters, hydrologists, researchers, farmers, ranchers, engineers and many others.

Interested volunteers can learn all the details at CoCoRaHS.org. Many helpful video tutorials are available on YouTube, too.

By Jodi Torpey
A Denver Master Gardener