- Author: Ali Williams
- Editor: Maggie Mah
- Editor: Cynthia Nations
enticing and the task seems simple enough: just lay it on the soil, cover with an attractive layer
of mulch and the foul demon weeds that lie in wait will wither and die in the darkness. At last,
you will be free from the tyranny of weeding! Hang on--there's more you should know about
this stuff! Although the promise of a neat, easy to maintain landscape may be hard to resist, the
reality isn't quite what it's cracked up to be, and you may end up doing more harm than good.
scale agriculture operations and to provide stability for structures such as retaining walls. Weed
Manufacturers claim that the materials are permeable, help to retain moisture, prevent weeds
from growing, and can therefore reduce the need for chemical herbicides.
Does it work? Landscape fabric does help to suppress weeds, but the effect is only temporary.
When freshly laid down, fewer weeds will appear on the surface because seeds that are already
opportunistically seek tiny holes in the fabric and utilize pinpoints of light to sprout through the
fabric-mulch layer and emerge triumphantly on the surface. You might admire their tenacity
before pulling them out but unfortunately, the tough fabric covering makes it difficult to get at
the root--a crucial aspect in the battle against weeds. Most likely, a bigger hole has also been
created in the process, making it easier for more weeds to germinate.
Is it permeable? Landscape or “weed blocking” fabric is made of tightly woven fiber, usually
polyester or plastic, both of which are derived from petroleum. There are different grades and
thicknesses, which will have correspondingly different degrees of permeability. Initially, they
are somewhat porous, allowing a certain amount of water and air to move through the fabric.
Unfortunately, permeability decreases in short order as the small holes that create porosity
gradually become clogged with dirt and debris. This is where the trouble starts.
What goes on below the surface? While not visible to the naked eye, healthy soil teems with
billions of beneficial organisms that depend on the movement of water and vital gases (oxygen,
carbon dioxide) between the atmosphere and the soil. As permeability decreases, these
components become more and more restricted. Deprived of oxygen, carbon dioxide and water,
soil microorganisms die off, leading to a downward cycle. Natural processes start to shut down
and plants start to appear less and less healthy. Once uncovered, the degraded soil may appear
cracked, compacted, and will very likely smell rotten. This is because the natural process of
decomposition has been interrupted and the healthy microbial community has died off.
Rooting for roots. Plants that are surrounded by increasingly clogged landscape material have a
hard time, too. Vegetation that is planted in good, properly irrigated soil grows deep roots in
the process of seeking out nutrients and moisture. This leads to healthy plants that are more
resilient to stress. Conversely, plants that are surrounded by a cover of landscape fabric (which
can be bone dry even after a deep, soaking rain) soon spread their roots out closer to the
surface. Eventually, roots may appear at the edge of the landscape fabric but despite a
gardener's best efforts, plants in this scenario will not do well.
Mulch: always good? Landscape fabric is often topped with a layer of organic mulch such as
wood chips. Although mulch is normally a very good thing and a top dressing of it certainly
looks more attractive than naked landscape fabric, it can't do what it does when it is in direct
contact with the native soil and becomes counterproductive. Why? Instead of the usual process
of decomposing and adding valuable organic matter to the soil, the mulch particles just break
down on top of the fabric and add more particulates to clog things up even more.
Still in the weeds? If you are determined to get the upper hand in the battle against weeds,
consider sheet mulching and other beneficial practices that will minimize time and effort and,
at the same time, help your garden to thrive.
Trees and Shrubs
Trees and shrubs usually have an easier time getting through the winter if they are in good shape. However, if a freeze is forecasted, one of the most important things to do is to ensure they have been watered 2-3 days prior, especially if autumn has been dry. As with perennials, mulching with fallen leaves or other mulch will help protect the roots, but do not have mulch up against the tree trunk or plant stem, which could cause rot to occur.
Wrapping trunks of young trees with blankets, towels or piping insulation will provide added protection.
Wait until after the first frost, then gently dig up the bulbs or tubers. Cut away any leaves and brush off as much soil as possible. Let them dry out in a cool spot for about a week. Label them so you'll remember what they are! Pack them in a breathable box, such as a cardboard box, storing the bulbs so they don't touch each other, and cover them in sawdust or shredded newspapers. Keep them in a cool, dark location that is below 45°F, but doesn't freeze.
Citrus plants can be protected by frost cloths which allow some light and air to penetrate and can stay on plants for a few days at a time. They can also lay directly on plant foliage. If you use other type of cloth such as burlap or cotton sheets, use stakes to hold the cloth away from the plant greenery. Remove it during daytime when temperatures are above freezing and sunny, and replace it each night prior to sunset. Whatever cloth you use, make sure the cloth goes all the way to the ground to capture radiant heat from the ground. If there is mulch around the plant, rake away during the day, if above freezing and sunny, to allow the soil to warm up.
Some roses are more sensitive to cold than others. As a group, hybrid tea roses are the most vulnerable. Make sure they are watered prior to predicted freezing temperatures, protect the root zone with mulch on the soil mound. You may also wish to cover your sensitive roses with frost cloths.
What do do if frost damages your plants? Wait!
Frost damage occurs when the water inside the cells of a plant freeze, causing damage to the cellular walls, which harms the overall health of the plant. Frost damaged vegetation will wilt, turning brown or black, as if they have been scorched. The bark may crack, or split. In severe or prolonged periods of frost the plant can die.
If you see what appears to be frost damage, wait until late spring until all chance of frost has passed. Plants are resilient and can often recover on its own, producing new growth. Pruning what seems to be damaged branches too soon can cause significantly more trauma, even death, to a vulnerable plant that might otherwise have recovered in the spring.
Denise Godbout-Avant has been a UC Cooperative Extension Master Gardener in Stanislaus County since 2020.
Does growing a vegetable garden sound like something you'd like to do, but you don't feel equipped? So, here's the deal. Find some dirt, and then plant. It's that simple. If you want to grow food, the first step is to find some dirt. Consider the usable ground you have. Take a look around. Maybe it's that patch of front lawn that you're tired of mowing, or haven't mowed at all. Could it be the bare spot in the back where the dog likes to poop? Step One is to find some dirt, and don't be judgy about the dirt you have. Your dirt is full of potential.
Your objective is to give your dirt some tender loving care, and your soil will return the favor by giving you healthier plants and better produce. Your soil's mineral composition is what it is, but one element we can be altered is organic material. No matter what kind of dirt you have, adding organic matter will make it better. Organic materials include grass clippings, fallen leaves, straw, wood chips and bark, hulls, plant clippings (chopped small) and everyone's favorite...manure. Now, here's an important point: it takes time for the organic materials to break down and start to enrich the soil, to become usable to plants. So, what's the best and quickest way to get those things into your soil? Compost. Compost is already mostly decomposed organic matter, so it mixes into the soil and continues to decompose slowly, releasing nutrients to plants and improving soil texture. Compost costs money, but you can also make your own in as little as 2 to 3 weeks at little or no cost. This article has a complete description of DIY compost: Compost in a Hurry (UC ANR Publication 8037).
Think of mulching as another method of composting that involves placing a thick layer of organic matter on top of the soil and letting it decompose very slowly. It's even better to put a layer of newspaper or cardboard on the ground first, wet it, and then spread out the organic material on top, about 4 inches thick. The organic matter and the paper or cardboard underneath will break down over the next 6 to 10 months. To add plants, push aside the mulch, expose the paper or cardboard, and cut an "X" large enough to accommodate your plant. Fold back the flaps, dig a hole, and add your plant. When done, lay the flaps back in place and re-cover with mulch. Remember that front lawn that you're thinking could be a vegetable garden? This method of sheet mulching is one way you get rid of the grass! Cover it, mulch it, forget about it. If you want to learn more about lawn removal, here's an article containing complete instructions: Lawn Removal: Do It Right.
UC Master Gardeners of Butte County are part of the University of California Cooperative Extension (UCCE) system. To learn more about us and our upcoming events, and for help with gardening in our area, visit our website. If you have a gardening question or problem, email the Hotline at firstname.lastname@example.org or leave a phone message on our Hotline at (530) 538-7201. To speak to a Master Gardener about a gardening issue, or to drop by the MG office during Hotline hours, see the most current information on our Ask Us Hotline webpage.
- 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>
Ask Master Gardeners about mulch and they will start ticking off benefits: protects soil from compaction and extreme temperatures, improves soil structure and feeds soil microbiology, suppresses weeds, retains moisture, supplies nutrients, and supports the soil food web. But not all mulch is created equal. One mulch, arborist wood chips, can accomplish everything on the list, but isn't suited for use around veggies and delicate annuals; other mulches admirably fill those and other niches, and then there are a few that should generally be avoided.
First, what is mulch? Basically, anything that covers the ground. It can be organic, synthetic, or rock. It can even be a living ground cover. Vegetables are often mulched with straw or some mixture of shavings and manures – materials that not only protect the soil but rapidly break down. Trees, shrubs and woody perennials benefit from woody mulches that last years and feed both roots and soil biota. Flower beds can thrive with their own cuttings serving as mulch as can smaller, more delicate shrubs.
Stone mulches – rocks, gravels, pebbles, and decomposed granite (DG), are good for fire-scaping and so are useful near buildings and to break up planting beds into islands that discourage fire spread. They protect the soil from adverse weather but do not feed it. Most people line stone material with landscape cloth to facilitate its removal when desired and to keep the stone on the surface rather than sinking into the root area. Unfortunately, the landscape cloth will at some point need to be hauled to landfill.
Then there are the green and animal manures. Green manures include grass, shredded leaves, and small garden clippings. Animal manures are rich in nutrients but need to be composted before use. They are typically mixed with green manures or soil amendments. These mulches are useful in kitchen gardens and annual flower beds.
Bark mulch looks good and can feed soil eventually, but its purpose is to repel water and germs while gardeners want to invite microbes and retain moisture in the ground. Bark can also float away with rain or irrigation.
Arborist wood chips, on the other hand, are usually delivered freshly chipped after arborists prune or remove trees. This is the best mulch in terms of moisture retention, weed control, and sustainability. This chipped material is mostly wood but also includes bark and some green material. Because of this variety in size it resists compaction, feeds the soil, and invites colonization by a diverse soil biota. Best, it's usually free.
- Inorganic mulches such as landscape cloth and plastic sheets can be useful in commercial farms, but they are less useful in home gardens and do not benefit the soil. Additionally, they deteriorate rapidly into landscape trash.
- Cocoa bean: this mulch was popular for a while because of its deep brown color and chocolate smell. But not only does it tend to become moldy if applied too thickly and to blow away easily when dry, but it is poisonous to dogs.
- Rubber mulch: Typically made out of tires it contains the same heavy metals tires have – cadmium, chromium, and zinc. As the mulch breaks down, these metals are released into the soil.
With all the good mulches to choose from, gardeners shouldn't forget living plants. Think about carpets of creeping thyme or meadows thick with clovers. They feed and protect the soil, suppress weeds – and do it all while looking great and attracting pollinators to your garden. What's not to like?