Mulching is one of the most beneficial practices a gardener can use for his plants’ better health. Mulches are different materials placed over the soil surface to maintain moisture and improve soil conditions.
This cheap, time-saving, and eco-friendly process is one of the best things you can do to keep your soil healthy, as long as you make sure you’re doing it right.
The best time-saving thing a gardener owner can do is to apply mulch. This goes for everywhere from vegetable gardens to flower beds. Mulched gardens are healthier, have fewer weeds, and are more drought-resistant compared with the unmulched ones. When it’s done properly, it’ll allow you to spend less time on weeding, watering and fighting pests.
There are 2 basic kinds of mulching:
Organic mulches include formerly living material such as: chopped leaves, straw, grass clippings, compost, wood chips, shredded bark, sawdust, pine needles and even paper.
Inorganic mulches include: gravel, stones, black plastic, and geotextiles (landscape fabrics).
Both types discourage weeds, but organic mulches also improve the soil as they decompose. Inorganic mulches don’t break down and enrich the soil, but under certain circumstances they’re the mulch of choice. For example, black plastic warms the soil and radiates heat during the night, keeping heat-loving vegetables such as eggplant and tomatoes cozy and vigorous.
1. Mulching with organic materials
There are 2 cardinal rules for using organic mulches to combat weeds:
First, be sure to lay the mulch down on soil that is already weeded, and
Second, lay down a thick-enough layer to prevent new weeds from coming up through it. It can take a 4- to 6-inch layer of mulch to completely discourage weeds, although a 2- to 3-inch layer is usually enough in shady spots where weeds aren’t as troublesome as they are in full sun.
Using bark mulch + wood chips: You can purchase bags of decorative wood chips or shredded bark from a local garden center to mulch your flower garden and shrub borders. A more inexpensive source of wood chips might be your tree-care company or the utility company. They may be willing to sell you a trunk load of chips at a nominal price. Many community yard waste collection sites offer chipped yard debris or composted grass clippings and fall leaves to residents for free (or for a small fee).
Using shredded tree leaves: If you have trees on your property, shredding the fallen leaves creates a nutrient-rich mulch for free. You can use a leaf-shredding machine, but you don’t really need a special machine to shred leaves—a lawn mower with a bagger will collect leaves and cut them into the perfect size for mulching.
You can spread a wood chip or shredded leaf mulch anywhere on your property, but it looks especially attractive in flower beds and shrub borders. Of course, it’s right at home in a woodland or shade garden. Wood chips aren’t a great idea for vegetable and annual flower beds, though, because you’ll be digging these beds every year and the chips will get in the way. Anyway, they do serve well as mulch for garden pathways.
Using grass clippings: Grass clippings are readily available mulch, although it’s a good idea to return at least some of your grass clippings directly to the lawn as a natural fertilizer (see the Lawns entry). It’s fine to collect grass clippings occasionally to use as mulch, and the nitrogen-rich clippings are an especially good choice for mulching vegetable gardens. Your vegetables will thank you for the nitrogen boost!
Using compost: If you have enough compost, it’s fine to use it as mulch. It will definitely enrich your soil and make your plants happy, but keep in mind that when any kind of mulch is dry, it’s not a hospitable place for plant roots.
So you may want to reserve your compost to spread it as a thin layer around plants and top it with more mulch, such as chopped leaves. That way, the compost will stay moist and biologically active, which will provide maximum wellness for your plants.
Using pine needles (or pine straw): Affordable, attractive, and easy to apply, pine needle mulch — also known as pine straw — has a multitude of benefits in the home garden. Not all plants tolerate the acidic soil created by pine needles, while other plants, from berries to vegetables, thrive with pine needle mulch, so plant accordingly.
Using pine needle mulch benefits plants in many ways, without the use of harsh chemical products. Mulch prevents weed growth and helps soil retain water, keeping plants hydrated. Pine needle mulch, in particular, allows soil to breathe and doesn’t become dense and compacted. As it decomposes, pine needle mulch infuses soil with valuable nutrients like calcium, nitrogen and phosphorus. A layer of pine needle mulch also protects plants and soil during winter and from intense summer sun. Despite what you may have heard, using pine-needle mulch will not make your soil significantly more acid.
Using straw + hay: Another excellent mulch for the vegetable garden is straw, salt hay, or weed-free hay. It looks good and has most of the benefits of the other mulches: retaining soil moisture, keeping down weeds, and adding organic matter to the soil when it breaks down.
But be sure the hay you use is weed and seed free, or you’ll just be making trouble for your garden. And don’t pull hay or straw up to the stems of vegetables or the trunks of fruit trees or you’ll be inviting slug and rodent damage.
Advantages of mulching with organic materials
Spreading organic mulch saves labor and nurtures plants by preventing most weed seeds from germinating (the few weeds that do pop through the mulch will be easy to pull) and by keeping the soil cool and moist in summer. It decomposes slowly, releasing nutrients into the soil drop by drop.
Disadvantages of mulching with organic materials
Unfortunately, nothing is perfect. When using organic mulches bear in mind the following:
– As low-nitrogen organic mulches such as wood chips and sawdust decay, nitrogen is temporarily depleted from the soil. Fertilize first with a high-nitrogen product such as blood meal or fish meal to boost soil nitrogen levels.
– Organic mulch retains moisture, which can slow soil warming; in spring, pull mulch away from perennials and bulbs for faster growth. Wet mulch piled against the stems of flowers and vegetables can cause them to rot; keep mulch about 1 inch away from crowns and stems.
– Mulch piled up against woody stems of shrubs and trees can cause them to rot and encourages rodents, such as voles and mice, to nest in the mulch. Keep deep mulch pulled back about 3 to 4 inches from trunks. In damp climates, organic mulches can harbor slugs and snails, which will munch on nearby plants; don’t spread mulch near slug-susceptible plants.
– Organic mulches are usually more or less acidic, depending on their content; Mix some lime with the mulch beneath plants that prefer neutral or slightly alkaline soil.
You can always double mulch to stop weeds
If you know that a garden bed is filled with weed seeds or bits of perennial weed roots, use a double-mulching technique to prevent a weed explosion. Set plants in place, water them well, then spread newspaper and top it with organic mulch.
2. Mulching with plastic materials
Mulching a vegetable garden with sheets of black plastic film can do wonders. When it’s spread tightly over a smooth soil surface, black plastic will transmit the sun’s heat to the soil beneath, effectively creating a microclimate about three degrees warmer than an unmulched garden. Because the plastic film remains warm and dry, it protects the fruits of vining crops such as strawberries, melons, and cucumbers from rotting and keeps them clean. And of course, the mulch prevents weed growth and retains soil moisture.
Infrared transmitting (IRT) plastics cost more than standard black plastic, but they can result in even higher yields. These plastics warm the soil as well as clear plastic does, but also control weeds as well as black plastic does.
In raised bed gardens, lay down a sheet of plastic over the entire bed. Bury it at the edges or weigh the plastic down with rocks. Then punch holes in it for the plants. A bulb planter makes quick work of hole cutting. Sow seeds or plant transplants in the holes.
Because water can’t permeate plastic, the mulch retains soil moisture but it also keeps rainwater from soaking the planting bed. Thus, the ideal watering system for a plastic-covered bed is soaker hoses or drip hoses laid on the soil surface before you put down the plastic.
But don’t use plastic as mulch under shrubs. Although it keeps out weeds and can be camouflaged with decorative mulch, black plastic destroys the shrubs’ long-term health. Because water and air cannot penetrate the plastic, roots grow very close to the soil surface—sometimes right beneath the plastic—seeking moisture and oxygen. The shallow roots suffer from lack of oxygen and moisture and from extremes of heat and cold. Eventually the plants decline and die. Stick to organic mulches such as shredded leaves, bark, wood chips, or compost under your trees and shrubs.
Drawbacks of mulching with plastic material
Even though black-plastic mulch seems like a great boon to organic gardeners, its use is still not carefree. One issue of concern with black plastic is its manufacture (it’s a petroleum product) and its disposal—there are very few places it can be recycled. If you carefully lift black plastic at the end of the growing season and store it in a dry place over winter, you should be able to reuse it for several years, but eventually if will become torn and you’ll have to throw it away.
An alternative is biodegradable plastic mulch (cornstarch based). These materials are designed to break down in place by the end of the growing season, and you can dig any remaining bits into the soil. However, one of the breakdown products of biodegradable plastic mulch is carbon dioxide. Black paper mulch made from recycled paper is also available, but these products are usually treated with a synthetic antimicrobial substance to prevent them from breaking down too quickly.
Unlike black plastic, landscape fabrics let air and water through to the soil beneath while keeping weeds from coming up. But landscape fabrics (geotextiles) have some of the same drawbacks as black plastic. To begin with, they are petroleum products. When exposed to light, they degrade over time, so to make them last longer, you have to cover them with second mulch (they’re ugly, so you’d want to, anyway). However, many gardeners have discovered that shrub roots grow up into the landscape fabric, creating real problems when you eventually want to remove it. And weeds that germinate in the surface mulch send roots down into the fabric, too, tearing it when you pull them out.