A: The horrible smell comes from organic matter decomposing where there's not much oxygen. Potted plants that are overwatered provide exactly this situation. Perhaps the drain hole became plugged.
Mixing activated charcoal (1/3 cup) with four quarts of the organic potting soil and providing proper drainage normally reduces the odor in indoor plants.
Mould lives in moist environments. Just as you'd find mould on mushy old vegetable or damp walls, you'll find it on wet soil. It likes to grow somewhere that stays moist and doesn't move. Your plants are more likely to grow mould if they're somewhere with poor air circulation.
Potting soil has gone bad if it has a foul odor, mold growth, pest infestation, a compacted texture, or if it fails to retain moisture properly.
No, it's fine... mold isn't harmful to anything other than dead organic material.
Luckily, getting rid of mold on soil is relatively easy. You can scrape mats of fungus off the soil surface and throw it away, or replace the soil entirely with fresh potting mix. Another common way gardeners choose to get rid of mold on houseplant soil is by improving soil drainage.
Cinnamon is a staple in my plant care routine and I have been using it to treat mold and mildew on my soil for years!!
In the previous growing season, plants used nutrients in the potting soil that were added when it was manufactured. Nutrients also leach out from the soil as plants are irrigated. Gardeners who opt to reuse potting soil this season will need to improve the porosity and fertility of the soil before planting new plants.
Mold on soil usually appears as small to large white, fuzzy patches on the growing medium's surface.
House plants that get too much water can develop root rot which can produce a musty smell.
When was the last time you changed the soil in your container plants? If it's been awhile, and your plants aren't performing well, maybe it's time you looked into it. Typically, changing the soil in your potted plants should happen every 12 to 18 months.
SOIL DRAINAGE
Sour smelly soil often means it has poor drainage. Most of the soils in the Salisbury region are clay soils. Generally, they have good water holding capacity and mineral content, however, they also have poor drainage which can lead to waterlogged plants that die in winter.
gc gardener, we are sorry that you are unhappy with Miracle-Gro All Purpose Garden Soil. The odor is caused by decomposing natural material and is non-toxic. Once material is opened and spread, odor will dissipate on its own in 24 - 48 hours.
Steaming: Steaming is considered one of the best ways to sterilize potting soil and should be done for at least 30 minutes or until the temperature reaches 180 degrees F (82 C). Steaming can be done with or without a pressure cooker.
If the soil smells bad (like a swamp) or slightly sulphurous, that's another good indication that you may have some rot to deal with. This smell is a result of the bacteria that grow in anaerobic conditions, like the bottom of a pot with wet soil and nowhere for the water to go.
Mold. Your soil is bad if it has mold growing on it. This usually happens when you store moist soil in closed bags for a long time, especially during warm weather. Avoid using this expired potting mix since it could cause root rot in container plants.
There are almost countless uses for cinnamon in the garden: it can be used as a nature-friendly pesticide, a repellent against annoying insects, or as a catalyst to promote root growth in plant cuttings.
Prevent Fungal Disease
MAKE IT: Mix 1 teaspoon of baking soda and 2-3 drops of liquid soap in 1 liter of water. Spray the solution on the infected plants. Baking soda helps the plants become less acidic and prevents fungal growth.
How do I fix soil that smells like ammonia? Add organic amendments to improve drainage or aerate compacted soil. Fibrous organic amendments like peat, wood chips, tree bark, and straw are most effective for soils that are heavy, dense, or waterlogged.
Compost heap - Here is the easiest option of all: Simply toss the old soil or unused half-bags of soil right on the compost bin. A good compost pile should be a balanced mix of green material, brown material and soil.
Fortunately, most potting soil can last up to two years because that is the lifespan of the peat moss it likely contains. (Tip: To keep it as fresh as possible, store it sealed in its original bag or another covered container in a climate-controlled environment.)
There are a few ingredients you can find in almost any kitchen that will help to combat mold in your houseplant's soil. These natural anti-fungals include cinnamon, apple cider vinegar, and baking soda. Cinnamon can be lightly sprinkled on your plant's soil once a week until the mold growth has stopped.
Cinnamon fungicide control
Damping off disease is a fungus-based problem that hits small seedlings just as they begin to grow. Cinnamon will help prevent this problem by killing the fungus. It also works with other fungal problems exhibited on older plants, such as slime mold and with deterring mushrooms in planters.
If the potting soil has just been used one season and all the plants were completely healthy, sure. However, if you know your plants ended up hit with downy mildew, or other plant disease, you'll want to either toss the soil or spend some time sterilizing it.