- Author: Denise Godbout-Avant
People often rake their leaves and put them out to be picked up as trash. I have always preferred to leave the leaves for my garden.
If you take a walk in a forest, you'll see leaf layers several inches deep around trees and bushes. Fallen leaves have a complex relationship with trees and nature, providing many benefits which can be reproduced to some extent in our gardens.
Fallen leaves have the same weed suppression and moisture retention properties of shredded wood mulch—and they're free! Where mulch is desired as a decorative element, what could be more seasonally appropriate than a pile of brightly colored fall leaves? This natural mulch also provides insulating winter cover from cold temperatures for roots, seeds, and bulbs.
A Web of Life in Leaf Litter
Leaf litter isn't just free fertilizer and mulch. It provides food and shelter for a wide variety of living things including spiders, snails, worms, beetles, millipedes, mites, toads, frogs and more—these in turn support mammals, birds, reptiles, and amphibians that rely on these creatures for food.
Detritivores (organisms that eat dead or decaying plants or animals) break up and excrete leaf litter. Fungi and bacteria then take over and complete the recycling process converting these smaller pieces into nutrients which then sustain neighboring plants. They in turn help support biodiversity by becoming food themselves.
Numerous bird species such as robins and towhees forage in the leaf layer searching for insects and other invertebrates to eat.
Raking up leaves and putting them in the trash could have the unintended consequence of removing some of next year's garden butterflies and moths, many of which are pollinators. Most butterflies and moths overwinter in the landscape as an egg, caterpillar, chrysalis, or adult. In all but the warmest climates, they often use leaf litter for winter cover. Fritillaries and wooly bear caterpillars will tuck themselves into a pile of leaves for protection from cold weather and predators. Some Hairstreaks lay their eggs on fallen oak leaves, which become the first food of the caterpillars when they emerge. Swallowtail butterflies disguise their cocoons and chrysalises as dried leaves, blending in with the “real” leaves.
Bumble bees also rely on leaf litter for protection. At the end of summer, mated queen bumble bees burrow an inch or two into the earth to hibernate for winter. An extra thick layer of leaves is welcome protection from the elements.
All of which makes leaf litter an integral part of a complex web of life.
What You Can Do
Composting leaves is a terrific way to recycle and create a nutrient-rich garden soil amendment at the same time. Some gardeners opt for shredding their fall leaves for use in compost piles. Like people who mulch their lawn leaves with a mower, consider leaving some leaves undisturbed in garden beds and lawn edges. If space allows, you could create a leaf pile, allowing it to break down naturally, or add the leaves gradually to your compost pile over time. Such efforts will keep leaf litter critters safe and allow you to benefit from the rich garden gift that falls from the trees above.
While it is ideal to “leave the leaves” permanently—for the benefits mentioned above—if you do decide you need to clean your garden and remove the leaves in spring, try to wait until later in the season, so as to give the critters that have been protected by fallen leaves over the winter time to emerge and depart.
Some gardeners may be concerned that autumn leaves, matted down by rain or snow, could have a negative impact on their perennials. However, a thick layer of leaves provides additional insulation against chilly weather and protects newly planted perennials from frost which could damage tender roots and shoots. Anyone who has spotted fragile spring seedlings popping up in the woods knows that all but the most fragile of plants will erupt through the leaf litter in spring without trouble.
So, leave the leaves. While you can't perfectly emulate a forest, your garden will be healthier and more diversified, you'll help support a vast array of wildlife, and you'll reduce the strain on landfills.
Denise Godbout-Avant has been a UCCE Stanislaus County Master Gardener since July 2020./h3>/h3>/h3>
- Author: Heidi Aufdermaur
Have you ever had a hobby that turned into an obsession? One of my hobbies is gardening of course, as a Master Gardener. Not too long ago, I acquired a chipper/shredder. One of my gardener friends had two and sold one of them to me at a fair price. I have always wanted one, dreaming of all the rich mulch I could make with my own waste.
I was excited to use it for the first time, donned the earplugs and safety glasses and got busy. Of course, I had to first collect the yard waste. I started coveting all the potential material that I thought would be suitable to shred or chip. I collected from my yard first, then one morning on the daily walk with my husband and soon after Christmas, I had a new insight for all the Christmas trees that were being discarded on the streets. I commented to my husband about collecting some of them to chip. To my surprise, I came home one day from running errands and found about 6 Christmas trees piled up in our yard. My heart fluttered with excitement. I was worried that adding too many of the pines would change the pH of my soil so I consulted Ed Perry, our former Environmental Horticulture Advisor for Stanislaus County. He said I could compost and chip away, as I was adding other species to the mix and it would take a lot more pine trees to make any difference in the pH of my soil.
I started seeing all the shrubs and trees in our yard that needed a good trim and piled them up to dry for a while. I also added some spent flowers to the pile. What I learned about shredding flowers is to cut off the seed heads (if I didn't want them to germinate where I spread the final product). I learned that after I had shredded some old marigold plants, spread the mulch in a pathway between my vegetable rows, I soon had marigolds sprouting up all over. I transplanted a few, left a few and pulled the rest, adding them to the new pile before they flowered.
I began to explore the surrounding yards in our neighborhood. Leaves and clippings looked like gold to me. My neighbor was extremely happy to let me rake her lawn of all the beautiful leaves that had fallen. To say the least, I have become somewhat obsessed with this new habit of gardening. I am also pleased that I am not adding all this waste to the green can for a trip to the land fill.
Did you know there is an assembly bill (AB341) that requires communities to divert yard waste from landfills and recycle it? With the rapidly depleting landfill capacity in California, 75% of yard waste is to be recycled. This goal was to be achieved by 2020. This bill requires every commercial business, institution, and apartment building to implement recycling programs.
Even though this bill focuses on businesses and large complexes, it's also good practice for homeowners. Keeping your yard waste on site, adding it to a compost pile or breaking it down by running over small portions with a lawn mower, one can keep this valuable commodity in one's own yard. Some benefits of mulch include reducing water loss to evaporation, moderates soil temperature, reduces weed growth thus making weeds easier to manage and reduces dust in drip-irrigated landscapes.
So, if you become obsessed like me, just think of all the good that happens when collecting your yard waste and keeping it on site. Happy Gardening.
- Author: Ed Perry
If you're interested in making your own compost, the perfect time to start is in fall. A light covering of leaves on the surface of your lawn can simply be shredded with your lawn mower and left in place. They will decompose rapidly and add valuable nitrogen and organic matter to the soil. Once the leaf layer becomes too thick, you must begin raking them up for your compost pile.
Some gardeners simply pile the leaves in one place and allow the composting process to proceed slowly. However, if you want finished compost quickly, you'll want to use the “rapid” or “hot” composting method. Rapid or hot compost is made by manipulating the decay process, which is done by balancing food, water and air in the compost pile to favor the growth of high temperature microorganisms. A byproduct of their activity is heat.
To construct a hot compost pile, you will need a combination of bulking materials and energy materials. Bulking materials, sometimes called “brown materials,” are dry, porous resources such as sawdust, wood chips or straw. They help aerate the compost pile but are too low in moisture and nutrients to decay quickly on their own.
Energy materials, sometimes called “green materials,” include grass clippings, fresh animal manures, fruit and vegetable waste and garden trimmings. These materials provide the nitrogen and carbon compounds needed for fast microbial growth. If piled without bulking materials, energy materials are too wet and dense to allow adequate air into the compost pile. Such materials may emit a rotten egg smell as they decompose.
To build a rapid compost pile, combine two parts by volume bulking materials with one part energy materials. Some other hints for a rapid compost pile include:
- Chop your raw materials into small pieces. For best rapid composting, the particles should be from 1/8 to 1/2 inch in diameter.
- Mix the types of raw materials, rather than layering them.
- A large pile holds heat better than a small pile; for rapid composting, make the initial pile at least a cubic yard (36” X 36” X 36”) in volume.
- Keep the pile moist, but not wet.
- Turn the pile once a week to aerate it.
The raw materials that you use in composting have their own microorganisms. There is no need to add starters or soil. If the rapid process is working properly, you can have ready to use compost in as short a time as 3 weeks. Even if it doesn't work that fast, you will still eventually have a valuable compost that you can use to enrich your garden soil.
Still have questions about composting?
Sign up for our Composting Basics class!
When: November 24, 2020 6-7:30 p.m. PST.
Where: on Zoom.
How: http://ucanr.edu/compost/2020 sign up by Nov 24 at 4 p.m. to receive a link sent the morning of the class.
Instructors: Master Gardeners Terry Pellegrini and Heidi Aufdermaur.
And remember, all classes are recorded so you can always watch it again later.
Hope to see you there!
Ed Perry is the emeritus Environmental Horticultural Advisor for University of California Cooperative Extension (UCCE) in Stanislaus County where he worked for over 30 years.
- Author: Denise Godbout-Avant
Why do some trees change color and drop their leaves before winter? And why are there different colors?
Leaves are colored by pigment molecules. Most leaves appear green because they contain an abundance of the pigment chlorophyll. Chlorophyll is the site of photosynthesis where the sun's energy is converted into the carbohydrates that are plants' food source. During the cold winter months when there is less sunlight, it would take too much energy for some trees to keep their leaves healthy. So deciduous trees lose their leaves for the winter. Evergreen trees have a different strategy for dealing with winter's challenges (which is a topic for another time!).
Elevation, latitude and weather all affect the timing and intensity of fall colors. Higher elevations and northern latitudes produce earlier autumn colors in trees. In general, autumn weather with lots of sunny days, dry weather, and cold, frostless nights will produce the most vibrant palette of fall colors. Some trees that can produce vivid colors include maples, gingkos, aspen, birches, Japanese maples, liquidamber, cherry, redbud, Chinese pistache, and dogwood.
In the Central Valley we usually don't get the glorious colors like the Sierra Mountains or the east coast, but we do get some color which usually starts in early November. So, enjoy the autumn jewels since it occurs only for a brief period each fall!
Denise Godbout-Avant has been a UCCE Stanislaus County Master Gardener since July 2020.
- Author: Ed Perry
Did you know that fallen leaves can become a valuable garden resource? You can turn these leaves into compost. Although low in essential plant nutrients like nitrogen, the leaves still contain small amounts of all the nutrients plants need and are a valuable source of soil-improving organic matter.
Get started by chopping the leaves into smaller pieces before adding them to the pile. You can use a chipper or a shredder if you have one. Otherwise, run over them with a lawn mower and then mix them into your compost pile. If you have a lot of leaves, you can store them after shredding in garbage bags or containers, then occasionally layer them into your compost pile over the winter to add air to the pile.
Sometimes certain green materials, like grass clippings, become matted in the compost pile. When this happens oxygen is excluded, and the composting process may stop. Adding leaves helps keep the grass clippings fluffed up and aerated.
If you're new to composting, keep in mind that the decomposition process works best if you mix equal volumes of carbon-rich, naturally dry plant material (dead leaves, dried grass, straw, and woody prunings) with nitrogen-rich green plant material (grass clippings, wilted flowers, green prunings, weeds and fruit and vegetable waste). This mixture allows a “carbon to nitrogen” ratio of 30 to 1, which is ideal for efficient compost production. You can produce compost slowly or quickly. Here are two methods:
The Slow Method
Build a pile of organic materials and let it stand for a year, when the compost will finally be ready for use. The advantage of this method is that it takes relatively little effort. However, some nutrients may be leached due to exposure to rainfall, and low composting temperatures may not kill some weed seeds and disease-producing organisms. For more information on this method, download the leaflet Composting is Good for Your Garden and the Environment.
Rapid Composting Method
This process produces compost in as little as 2 to 3 weeks but requires more effort. It allows you to produce large amounts of compost quickly. For more details about this method, you can download the leaflet Compost in a Hurry.
Many local nurseries and the Modesto Junior College offer hands-on composting classes. In the future, our UCCE Master Gardeners plan to offer composting classes. Keep in touch with us by signing up for our blog and following us on Facebook and Twitter @UCMGStanislaus to hear about upcoming classes and workshops.
Ed Perry is the emeritus Environmental Horticultural Advisor for University of California Cooperative Extension (UCCE) in Stanislaus County.