How To Loosen Compacted Soil in Pots? (Explained for Beginners)

House gardening or pottying is a favorite hobby with many homeowners.

Most of us have two or more house plants growing in pots either indoors or on our porches. Just like soil on the ground, it is important that you check on the soil you use for growing your plants regularly. 

Compacted soil can cut off air, water and nutrient flow to your plants. Some easy ways to loosen compacted soil includes poking the soil with a stick and adding aerating materials to the soil. 

Today, we will discuss what soil compaction is, the causes, how to fix it, how to soften compacted soil without tilling amongst other questions. 

What Does It Mean For Soil To Be Compacted?

How To Loosen Compacted Soil in Pots

When soil particles are compressed together, the pore areas between them are reduced.

Soils that have been heavily compacted have fewer big pores, a smaller overall pore volume, and, as a result, a higher density.

In other words, when the pores are compressed, the soil becomes denser and each liter of soil becomes heavier.

Compacted soils have a decreased rate of infiltration and drainage.  This is because larger pores efficiently transport water straight down through the soil than smaller ones.

Additionally, in compacted soils, gas exchange is slowed, increasing the probability of aeration-related disorders. 

Guides To Changing Soil in The Pot!...
Guides To Changing Soil in The Pot! (2021)

Soil compaction can increase soil strength.

However it requires roots to expend more force to penetrate the compacted layer. Conversely, soil compaction also leads to impeded root growth and affects root development.  

Here is an article I wrote on how to dispose old potting soil

What Causes Soil To Become Compacted?

Soil compaction in farms and even in pots can be caused by a number of reasons and they include:

  • Natural Phenomenon

Compaction can occur naturally as a result of freezing and drying. Drying and freezing are natural processes that affect the soil and its organic matter decomposition.

It may kill a portion of the living matter in the soil. 

The extent of which depends on the complexity of the factors and circumstances involved. Drying the soil typically results in decomposition of the organic matter in the soil and eventual soil compaction.

  • Flooding

Soils in pots can get compacted when there is an overflow of water to the soil. Pots get filled up easily during heavy rains or with unmonitored irrigation systems. This supports an anaerobic or non-oxygen environment. 

Suffocation of plant roots results in the death of beneficial bacteria, while anaerobic bacteria multiply. As a result, soils become compacted.

  • Heavy Machinery

The use of heavy machinery in agricultural farm produce is also a major cause of soil compaction.

Unfortunately, these machines have large axle loads and compact the soil beneath their wheel tracks with each pass. 

Compaction of soil by a machine is generally dependent on the soil toughness and the machine’s load.

This is a problem faced by large scale agricultural farms where manual labor cannot cover all the work activities. 

  • Traffic 

The level of traffic from heavy machinery used in large scale agriculture can also determine how much compacted the soil will be.

Increased machine passage over a soil results in an increase in its dry bulk density and cone index. 

This in turn results in compaction of the top soil and inadequate soil surface conditions for seed growth and development.

Ten passes of a heavy machine can affect the soil up to a depth of 50 cm. Foot traffic also contributes to soil compaction and it is recommended to not walk all over a growing space. 

  • Grazing Animals 

Trampling of the soil by grazing animals is also a cause of soil compaction.

The extent to which grazing animals degrade the land is dependent on the trampling intensity, soil moisture, vegetation cover, and land slope. 

The amount of soil compaction induced by an animal might range between 5 and 20 cm.

Also check out this article I wrote on how to fix waterlogged soil

How Do You Fix Hard Compacted Soil?

Hard compacted soil is something that can happen to soil both potted or ground soil. The best defense against soil compaction is to prevent it.

However there are a few things you can do to fix already compacted soil and make it usable again.

  • Aeration: When soil is compacted, there isn’t enough air going around for roots to use and develop. You can improve soil aeration by poking the compacted soil with a chopstick. With the chopstick, you can make holes through which you can water the soil. Once the water starts  draining easily, your soil is getting aerated. 

You could also add aerating materials such as perlite, vermiculite and peat moss. Mix the soil with these then add water for moisture. 

  • Bury or Replace Compacted Soil: Your potting soil could be old from overuse. If this is the case, then the best option is to bury the compacted soil with mulch or compost. You can also replace the soil with new soil entirely. This is especially recommended if the soil is already over a year old. 
  • Composting: Composting is a tested and tried method for fixing compacted soil. All you have to do is prepare compost e.g. vermicompost and add it to the soil. When you mix biologically active compost into your soil, the beneficial microorganisms in it will help soil aeration and oxygen flow.

Why Is My Potting Soil Compact?

If you have experienced soil compaction in your potted plants, then it could either of the following reasons: 

  • Heat: If your potted plants are outside and bare, during the dry summer , the heat could cause it to get hard and compacted. 
  • Underwatering: When your potted soil doesn’t get enough water, the peat moss in it becomes hydrophobic and starts rejecting water. To avoid this problem ensure you have a consistent watering schedule for your plant.
  • Old Soil: If you have had the potting for over a year it is best to change it. Especially for fast growing annual plant species. 
  • Flooding: During the wet season and there’s a lot of rainfall, your potting soil can get flooded from too much water. 

How Do You Soften Compacted Soil Without Tilling?

Compacted soil can make it really difficult for plants and flowers to grow heavily.

Over tilling contributes to soil compaction and there are ways you can soften the soil enough to get it aerated. If you have a vegetable garden, you can grow cover crops for a season.

The roots of the crops will penetrate the soil and loosen it. 

Also, adding organic matter to your compacted soil will go a long way in softening your soil before planting.

Mulching and composting provide the soil with healthy microbes. These microbes benefit the soil by encouraging aeration and easy water flow. 

You can also use a soil aerator to loosen the compacted soil. Soil aerators come as either plug or spike aerators.

They make holes in the soil so air and water flow is easy. 

Note that, whatever method you are choosing, it will take time for you to see results so it best for you to be patient at that. 

How Do You Aerate Soil In Potted Plants?

Soil in potted plants can become hard and baked especially when it is bare and exposed to the heat.

Regular aeration of the soil will prevent it from getting compacted. Adding aeration additives to the soil will ensure it is always well aerated.

Perlite, vermiculite and peat moss are common additives that can help soil aeration. 

You can also regularly loosen up your soil with a fork or chopstick to improve aeration. You need the chopstick to break clumps that might be soil.

Ensure you do not damage any roots while doing this. 

Regular composting and or mulching when your soil needs it also helps to keep it aerated.

Conclusion

Air flow is quite important in the soil and a blockage to that would mean the plant roots do not get enough oxygen resulting in wilted plants.

Compacted soil refers to blockage of the pore spaces in soil due to a compression force. 

Some of the causes of compacted soil include flooding, traffic, heat, old soil, heavy machinery, grazing animals and natural phenomena.

Aerating compacted soil in potted plants can be achieved through loosening of the soil with chopsticks. 

Adding compost and aeration additives are other common methods with which you can fix compacted soil.

As a gardener, this a problem you have probably come across and we are glad to help out with that. 

Written by Alex Kountry

Alex Kountry is the founder of HayFarmGuy and has been a backyard farmer for over 10 years. Since then he has decided to write helpful articles that will help you become a better backyard farmer and know what to do. He also loves to play tennis and read books

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