How Long Does Potting Garden Soil Last

How Long Does Potting Garden Soil Last

Potting soil is not the typical type of soil. It is very different from the soil in the ground. Most of the potting soil is usually labeled soil. What does this mean? How can it be soil and still be soilless at the same time? We will help you understand that in a while.

But first of all, you need to understand that potted plants do better in potting soil that in the natural soil found in the ground.

The main difference between natural soil and potting soil is the fact that natural soil is a product of rocks disintegrating over a long period.

Potted Plants

Potting soil, on the other hand, is manufactured using carbon-based elements. We would, therefore, be in order if we say that potting soil is artificial soil.

So you go to your favorite gardening store and get the best potting soil for your indoor plants. You then plant and the soil does not disappoint. With frequent watering, the plants grow, and bloom, thus creating an ambiance in your space.

A year down the line, you realize things are not the same, as the plants start drying up. You first suspect that the plants are getting old, but this is not the case. It is the potting soil degrading. 

How Does Potting Soil Get Spoilt

Potting soil loses its strength gradually, until a time when it cannot support the growth and development of the plants sufficiently.

So, while the soil still looks good and healthy, here are some indications that all is not well.

1. The Soil Exhibits a Finer Texture

Potting soil is naturally coarse, because of its components. The coarseness makes the particles not to be compact together, and consequently, air and water flow freely through the soil. The roots also have sufficient space to grow and thrive.

Soil Exhibits a Finer Texture

After a while, the potting soil may start becoming fine and compact. This is an indication that the constituent matter is decomposing. This will hamper the roots from growing freely as well as inhibit the free flow of water and air.

When you start noticing the finesses which are mostly between one and two years after first using the soil, then you know it is time to change the soil. The best to go about this is to remove half of the soil and replace it with new soil.

The old potting soil can be thrown into the garden or the compost pit. You can also mix it with more new soil and plant another flower in it.

2. The Soil gets infested with Pests and Diseases

Once the potting soil has been used for planting, it will remain exposed to the environment. As a result of the exposure, it gets infested with pests and diseases caused by fungus or mold. These micro-organisms will consequently attack the plants.

The solution to this is to sterilize the soil. You should always sterilize any old soil that you need to reuse. 

You can sterilize the soil in a microwave by heating it for a few minutes under high heat. You need to allow the soil to cool down before putting in the plants; otherwise, warm/hot soil will kill the roots.

If the soil was too decomposed, you can mix it with equal parts of the new soil.

3. Nutrients get depleted

Potting soil is usually complete with all the essential nutrients incorporated during the manufacturing process. It comes ready to use and does not even need extra fertilizer. 

After some time, however, you may realize that the plants are not as healthy as they have always been. This is an indication that the nutrients are getting depleted.

The solution to this is to make a habit of adding a small amount of slow-release fertilizer to the potting soil at least every three months to make sure the soil maintains a high nutritional value.

Major Constituents of Potting Soil

Potting soil is a product of different ingredients, some of which are the reason why the soil gets degraded. Some of the components are environmentally friendly, while for others it is hard to tell. The most common constituents of potting soil include:

1. Compost

Image Credits: Pyracantha

Compost is made by decomposing degradable household waste and other stuff such as twigs and leaves that fall off from trees. You can make compost from home and apply to your garden.

However, the compost used in potting soil is produced on a large scale, using wastes from forestry activities. This makes it biodegradable and very high in nutrients.

2. Coconut husks

Shredded coconut husks are used to make potting soil. This waste product has very high carbon quantities. It is one of the main products in potting soil because of its capacity to retain moisture for longer periods.

3. Rice Hulls

Rice hulls are obtained as waste from rice production. They are not produced in large quantities and for this reason, they cannot be used commercially. They are however available in gardening stores for use by gardeners who prefer making their potting soil at home.

4. Perlite

Fertilome Perlite 8qt Dry

Perlite is a product of volcanic activities. They are like crushed rocks and their main function is to provide aeration and improve the drainage of the soil. They do not add any nutritional value to the soil. They, however, absorb fluoride from water. Excessive fluoride causes indoor plants to turn brownish. It, however, does not affect outdoor plants.

5. Peat Moss

Hoffman 15503 Canadian Sphagnum Peat Moss, 10 Quarts

Peat Moss has been used for a long time in making potting soil. With advanced research skills, however, it is not environmentally friendly, because it contains high levels of carbon dioxide.

It is also the ingredient that causes potting soil to degrade faster. The advantage, however, is its high moisture retention property.

Their source, however, which is the northern bogs is also not sustainable, considering the demand is higher than the rate of production. Peat Moss can, therefore, be replaced with the ground coconut husks.

How long does Potting Soil Last?

Potting soil, depending on the constituents and how it is being used can last for up to two years. This is however under ideal conditions that rarely exist.

It is therefore advisable to keep testing your soil to ascertain whether it is still providing the nutrients that your plants need to thrive. If the soil consists of peat moss, it will expire even when it is stored in airtight bags. This is because peat moss decomposes naturally.

This is the reason why you will see an expiry date on the soil’s packaging. If the potting soil has exceeded its expiry date, then you should toss it irrespective of whether you had already used it or it was still in the bag.

For soil that is already in use, you should always note the expiry date somewhere in a planner or on the planter containing the soil. Once the expiry date approaches, you will need to replant the plants in new soil.

However, used soil does not survive long enough to reach the expiry date, as it gets depleted of nutrients with time. This is as a result of exposure to light, water frequently flowing through the soil and the nutrients being used up by the plants.


One of the indications that it is time to replace your potting soil is a pungent smell. When it expires it produces a bad smell that results from the growth of harmful fungus. The soil can also develop molds which will disappear when you expose the soil to air and sunlight.

The mold vanishing, however, does not mean that the soil can be used. If you want to grow healthy plants, then you need to get good soil.