Can I use my Christmas tree for mulch?
The boughs of fir, pine, spruce, and other evergreen trees are a good insulator for dormant perennials. Unlike some winter mulches, like unshredded leaves, they don’t pack down into a solid, oxygen-excluding layer. And when spring comes, they’re easy to rake aside.
Discarded Christmas trees appear curbside at an ideal time for adding winter mulch in my Zone 6 garden. By late December, the ground has chilled (if not frozen an inch or two deep) and plants are dormant. Hopefully, any field mice in the neighborhood have settled down elsewhere for the winter and won’t find habitat in my mulch. I scavenge the neighborhood before trash day, bringing home five or six trees to cut apart.
It’s quick and easy: Just snip the tree’s branches off with loppers. Place the boughs over the crowns of perennials or around roses.
The purpose of winter mulch is not to keep plants warm but to keep them consistently cold and dormant. Unmulched plants are exposed to temperature fluctuations, alternating between overnight freezing and daytime thawing when the sun hits the soil. Some plants shrug off these repeated temperature changes, but anything of marginal hardiness will appreciate the extra protection it gets from a layer of evergreen boughs. —Doug Hall
My vegetable garden is crawling with all kinds of insects. Should I be worried? I’m new to this and I don’t want to use chemicals if I don’t really need to.
There are millions of species of insects, so don’t feel bad if you don’t recognize them all. Most insects have no direct impact on the plants in your garden, even when you see them crawling on a leaf. Some insects provide valuable services by pollinating fruits and vegetables or by preying on pest insects. A few—the minority, really—are pests that can reduce the yield of crops or spoil the appearance of ornamental plants.
In my garden, instead of focusing on every insect that passes through, I keep an eye out for insect damage to leaves and fruits. When I spot some damage, my next step is to identify the culprit. Books, websites, and experienced gardeners (including the ones who are helping each other with gardening dilemmas in the discussion forums on this website) are helpful in identifying pests. Once I know what is causing the problem, I can do some online research to discover the best course of action. Some pests cause only superficial damage that doesn’t affect crop yields or quality. Many can be controlled through nontoxic means—a shot of water from the hose, hand-picking, or sticky traps, for example.
Once you know what insect pests are common in your region, you can prepare for them with growing techniques that protect your harvest: using floating row covers to exclude insects, for example, or timing crops to avoid the worst periods of pest pressure. As a last resort, you might want to consider spraying with an organic pest control, such as insecticidal soap or neem oil. Read the product label to make sure it is appropriate for both the plant and the insect involved, and take care to protect beneficial insects from the spray. —Doug Hall
Someone told me that sugar is good for plants. I sprinkled some around my vegetable garden this year but didn’t notice anything different. How much should I apply?
Plants don’t need you to add sugar to their soil; they make their own. Through the process of photosynthesis, which is powered in nature by energy from the sun, plants turn water and carbon dioxide into sugars. Plants use their self-made sugars as a fuel for growth and reproduction.
Sugar you add to the soil will instead feed soil microorganisms, such as bacteria and fungi. These naturally occurring microbes are nature’s recyclers; they help to nourish plants by breaking down the bits of organic debris in soil into their nutrient components—including the potassium, magnesium, nitrogen, and other elements that are essential for plant life. In this sense, sugar could benefit the plants in your garden by boosting the microbial population, thereby speeding up the rate at which nutrients become available.
But plants already have a process for encouraging microbial life. Soil scientists have discovered that plant roots exude sugars—sugars produced by photosynthesis—as a way of developing mutually beneficial relationships with microbes. By controlling the types and amounts of sugars they release, plants can select which kinds of microorganisms will colonize the soil around their roots. Not coincidentally, plants choose to feed the microbes that will provide them with the nutrients they need most. Compared to this sophisticated à la carte system, a sprinkle of processed sugar from your pantry is just junk food for bacteria.
By the way, there’s another reason some gardeners haul the sugar canister out to the garden. Sugar added to the planting holes of vegetable transplants is said to discourage root knot nematodes, a destructive soil-dwelling parasite that plagues many Southern gardens. —Doug Hall
As a new gardener, I’m not sure what I need to do to get my strawberry bed ready for winter. Do strawberries need protection?
A layer of loose mulch over the crowns of strawberry plants in winter shelters them from temperature fluctuations and keeps them dormant until spring arrives. Mulch also conserves soil moisture for these shallow-rooted plants. The only regions where winter mulch might not be needed are places with dependable, winter-long snow cover and, at the other extreme, places where the temperature never falls below 20°F.
Straw is the obvious choice for mulching a strawberry bed, but other lightweight mulches like pine needles and evergreen boughs also work. Don’t use mulches that become soggy and heavy—leaves, for example.
Allow your strawberries to go dormant before applying mulch. Applied too early in fall, the mulch can delay dormancy and become a haven for rodents. Wait until a hard freeze—between 20°F and 25°F—has flattened the leaves, then scatter 2 to 5 inches of mulch over the entire strawberry bed.
As growth resumes in early spring, rake the mulch into the pathways between beds—but keep it handy in case it’s needed to protect from late frosts. —Doug Hall