Potting soil should never have a foul odor. Take a whiff of a handful of the good stuff; it will smell rich and earthy, but it will not stink! Don't make this mistake – If it has a rotting smell, it means something is wrong and should not be used on your plants (It can introduce disease).
Smell really does tell you a lot about the soil.” According to Northern Illinois University, that fresh smell is a chemical byproduct of a small organism that indicates healthy, productive soil. Soil that smells rotten, like ammonia, is an indicator of bad drainage or lack of oxygen, as stated by the USDA.
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.
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.
So, what's responsible for that earthy smell? The smell is caused by soil-dwelling bacteria known as Actinomycetes, which thrive in the soil when conditions are wet and warm. When the soil dries up, these organisms produce tiny spores that release a chemical compound called geosmin (meaning “earth smell” in Greek).
Why does my soil stink? Overwatering, poor drainage, and a lack of aeration are frequently to blame for foul odors in the soil. Unpleasant odors in soil can also be caused by bacterial or fungal contamination of the soil or by using manure that has not been properly treated.
Smell of soil is due to the smell of two small molecules produced by small organisms. These small molecules are known as geosmin and 2-methylisoborneol (MIB). These compounds are mostly produced by bacteria belonging to the genus Streptomyces.
Healthy soils have a distinctive, earthy odor due to Actinobacteria and other beneficial microbes. Actinobacteria are present in a healthy soil and produce geosmin, which in turn produces a distinctive odor. Unhealthy soils often have a sour or metallic smell.
Unpleasant Smell
The soil may smell like pesticides or chemicals, instead of having the natural smell of earth and grass. In other cases, you may be able to smell the contaminant, like arsenic, which has a signature odor.
Smell can tell you if the soil is too sour (it will smell sour due to a low pH), which can be confirmed by a soil pH test.
Heat. Heating the soil is very effective and the soil can be used immediately after cooling, unlike chemically treated soil. Many plant pathogens are killed by short exposures to high temperatures. Most plant pathogens can be killed by temperatures of 140°F (60°C) for 30 minutes.
Good drying conditions over the next two days can significantly reduce the release of odors. In addition, the next two evenings are the most likely time when neighbors will experience odors.
How Long Can You Store Potting Soil? Opened bags of new potting soil can retain quality for around 6 to 12 months. For unopened and unused potting soil, you can store it for about a year or two before it goes bad. Usually, potting soil lasts longer when stored in a dry and cool container.
Signs of root rot are slow growth, mushy stems, and wilting, yellow, distorted leaves (especially when the plant has been well watered, as wilting leaves can also be a sign of a dry plant). Usually the soil will smell rotten and the roots will appear to be reddish brown.
The most common culprit of a rotten egg smell coming from plant pots is excessive watering. The bacterium causing the odor needs an abundance of water to live and breed. This excessive moisture leads to root rot, which can prove fatal to the plant. Removing the plant from the pot can confirm this diagnose.
That peat moss can decompose even if you never take it out of the bag. If your potting soil has been sitting in your shed since last year in an opened bag and it's gotten wet, toss it. If it somehow stayed bone dry, it should be OK to use.
Yes, moldy potting soil can be used on plants. The mold strains in the soil are harmless to plants in the large majority of cases. You can use and re-use the moldy potting soil without having to worry about your plant's health. However, you must take care of the mold proliferation causes, which is excessive moisture.
The smell of geosmin is unmistakable: It's the odor that permeates the air after a summer rain squall or fills your nose while gardening. It's the smell of wet soil—an earthy, almost comforting scent.
Compost is at risk of “going anaerobic” if the water content is above 65 percent or if the compost pile sizes are too large. This type of respiration will also produce sulfur compounds, which give off a rotten egg smell.
Symptoms of root rot or crown rot
Causes stunting, yellowing and wilting of plants even when potting media moisture is adequate. Roots are brown to black and soft or mushy. The outer portion of the root can be easily pulled away from the core which leaves a fine hair-like thread.
The smell of ammonia is an indicator that nitrogen is in excess, and carbon/energy is limiting instead. Ammonia losses are common when composting high nitrogen materials such as fresh grass clippings or manure, and are often accompanied by other nitrogen losses in runoff or infiltration.
You can reduce odors by preventing bacteria from growing in manure. Methods to reduce bacterial growth include killing bacteria with disinfectants, adding lime to raise manure pH, and keeping manure dry.
Manure that is piled and left alone will decompose slowly. This can take three to four months if conditions are ideal. It can take a year or more if the starting material contains a wide carbon:nitrogen ratio (as is the case when manure contains wood chips).