Mulch & Soil FAQs
What is growing in my bag of mulch or soil?
Why do I sometimes find mold or fungus growing inside a sealed bag of soil or mulch?
If you open a new bag of soil or mulch and find white mold or fungal spots, it's a direct result of moisture content. Mold and fungus thrive in moist environments containing organic matter. Since soil and mulch bags are not always perfectly waterproof, water content from the original packaging (especially in colored mulch, which retains moisture from the dyeing process) or moisture seeping in after packaging provides the ideal conditions for these harmless organisms to develop.
Is the mold I find in bagged soil or mulch safe to use, or is it harmful to plants?
The mold and fungus found in soil or mulch bags are generally harmless. They are natural organisms that help break down organic matter and contribute to the health of your garden, rather than damaging your plants. They pose no risk to people or pets, though wearing gloves when gardening is always a good idea.
What should I do if I notice mold or fungus growing on the outside of a bag of soil or mulch?
If you see mold on the exterior of a bag of soil or mulch, do not purchase it. This may indicate improper storage conditions and potential contamination. Unlike mold found inside the bag (which is often harmless), external mold suggests a compromised product.
Can the mold and fungus I find in bagged soil and mulch actually be beneficial for my garden?
Fungi, including mold and mushrooms, are essential components of a healthy soil ecosystem. These beneficial microorganisms perform a vital function: they break down organic material into readily available nutrients that your plants can easily absorb. This process is so crucial that we deliberately choose not to sterilize our growing media, ensuring we preserve these natural helpers that enrich the soil and foster balanced conditions for robust plant roots.
What should I do if I find a large amount of mold on my bagged soil or mulch?
If you notice a large, unattractive amount of mold, it's typically a sign that the soil or mulch is too wet. While this overgrowth is not harmful to your plants, you can easily reduce or eliminate it by exposing the media to sunlight and air.
- For Unused Soil/Mulch: Spread the product out on sheets of newspaper or a tarp and allow it to dry out before application.
- For Soil/Mulch that is already applied: Allow the area in your garden to dry out a bit by reducing the frequency of your watering.
The mold should naturally dissipate once the moisture level decreases. Remember to always wear gloves when handling any growing media product.
How Does Mulching Help?
It Adds Curb Appeal
Mulch is the key to achieving a finished, professional look in your yard. It immediately adds rich color and texture to areas like landscape beds, around trees and shrubs, or along your home's foundation. Choosing a colored mulch offers the added benefit of beautifully accenting and harmonizing with the existing colors of your home and flower gardens.
It Improves the Soil
Mulches made from wood and other organic materials are valuable because they actively improve the soil as they decompose. Over time, natural soil inhabitants like microbes and insects consume the mulch. The by-products of this natural consumption are released back into the soil as organic matter, leading to healthier, more fertile growing conditions.
It Protects Against Temperature Fluctuations
Mulch functions as an effective insulator, playing a critical role in regulating soil temperature throughout the year. It keeps plant roots cool during the heat of summer and provides essential warmth and protection during the winter months. This insulating property is particularly vital for tender, new plantings established in the fall, offering necessary defense as temperatures begin to drop dramatically.
It Conserves Moisture
Mulching directly contributes to reduced watering time because it acts as a barrier to moisture evaporation. By slowing down this process, mulch ensures that more water remains conserved in the soil, readily available to nourish thirsty plant roots.
It Helps Prevent Weeds
Applying a 2 to 3-inch layer of mulch provides a natural, effective barrier against weeds. This works by blocking sunlight and physically suppressing growth, which prevents weed seeds from sprouting and taking over your landscape beds.
How much mulch do I need?
| Area | Number of 42.5L bags at 5 cm (2") Depth | Number of 42.5 L bags at 7.5 cm (3') Depth |
|---|---|---|
|
2.2 m² (24ft²) |
3 |
4 |
|
4.5 m² (48ft²) |
6 |
8 |
|
6.7 m² (72ft²) |
8 |
12 |
|
8.9 m² (96ft²) |
11 |
16 |
Application Tips for Mulch
Should I remove old mulch before applying new mulch?
In most situations, there is no need to remove old mulch since it will naturally decompose and enrich your soil. The only time removal is necessary is if the layer is excessively thick (over 4 inches). If you choose to leave the old mulch, always be sure to loosen it up before adding a new layer. This simple step is vital for improving both drainage and airflow in the soil beneath.
How often should I mulch?
As a general rule, applying fresh mulch to your landscape or garden beds once a year is recommended.
What can I grow in a raised bed garden?
What grows well in a 15 cm (6") high raised bed?
Arugula, leeks, lettuce, onions, radishes, spinach, strawberries, basil, chives, cilantro, dill, mint, oregano, parsley, thyme, marigolds and other annual flowers
What grows well in a 30.5 cm (12") high raised bed?
Beans, beets, broccoli, Brussels sprouts, cabbage, cantaloupe, carrots, cauliflower, collards, cucumbers, garlic, kale, summer squash, Swiss chard, turnips, lavender, rosemary, sage, borage, calendula, cosmos, lantana, nasturtiums, snapdragons, sweet alyssum (plus everything in the 6" list)
What grows well in a 51 cm (20") high raised bed?
Artichokes, asparagus, eggplant, okra, parsnips, peppers, sweet potatoes, tomatoes, watermelon, winter squash, pineapple sage (plus everything in the 6" and 12" lists)
Caring for Your Raised Bed Garden
Feed your plants, one month after planting, with Miracle-Gro® Shake 'N Feed® All Purpose Plant Food 12-4-8, following label instructions. Using this plant food in combination with Miracle-Gro® Raised Bed Soil yields bountiful results. For the next growing season, you don't have to replace all the soil that has naturally broken down. Instead, simply refresh the old soil before planting by adding Miracle-Gro® Garden Soil All Purpose as directed on the package.
How much soil does your garden need?
| Area Surface | Number of Bags Required at 7.5 cm (3") Depth | Number of Bags Required 15 cm (6") Raised Bed |
|---|---|---|
|
2.2 m² (24ft²) |
6 |
6 |
|
6.7 m² (72ft²) |
12 |
12 |
|
8.9 m² (96ft²) |
24 |
24 |