Compacted Soil in Houseplants: How it Happened and The Risks Included

Why Is My Houseplant Soil Hard?

We’ll begin by discussing what caused the hard, compacted soil in your potted plants in the first place.

The Potting Soil Is Old

What is the age of the soil that you used for your plants? Even if there are no mold signs or pests, it doesn’t mean the soil will be preserved for life. The rule of thumb for how often to switch out your potting soil or potting mix is this: If your plant is a fast grower, then change out its soil about every three to six months. For plants that grow slowly, such as the snake plant, you can wait longer.

There may have been many waterings over the years, and there is still plenty of nutrients, fertilizer, and who knows what else in the old soil that creates blockages or limits air pockets in the soil and does not serve your houseplant well.

You Used the Wrong Type of Soil

It is not recommended to plant indoor plants in topsoil or to use outdoor soil to plant potted plants in general.

You can mistakenly grab topsoil for potting soil. The two types of soil can look very similar, so you may not notice that there is a difference.

Topsoil is designed for outdoor plants that are usually much larger than houseplants. These larger plants require a different soil to thrive.

For starters, the soil may weigh much more. The choice of the soil for potted plants and container gardening matters because the weight of the soil can indirectly affect the ability of the soil to remain aerated. Topsoil also contains a different combination of nutrients than the bag of potting soil that you need to be using.

You should also avoid using soil from your backyard, although it may seem convenient. Backyard soil is rarely pure soil at all and typically contains silt and clay. Your houseplants will not benefit from this since it does not contain the nutrients your potted plants need to be healthy.

The Aerating Materials Died or Were Flushed Away

These aerating materials help retain water and create air pockets in your container’s soil. For many plants, coconut coir, perlite, vermiculite, or peat moss create the perfect conditions for them to thrive.

Even then, peat moss still lives only for one to two years. When it’s dead, it is no longer absorbing water, and it is no longer aerating the soil either. The drainage holes in the pot can be washed with repeated watering with vermiculite pellets and bits of coconut coir.

The above scenario is essentially inevitable if you don’t stop watering your houseplant. You may not be able to tell when your potting mix is more dirt than perlite, but your houseplant will. What follows will be harder soil.

What Are The Risks of Compacted Soil?

Hard, compacted soil can cause a whole host of problems for your houseplant, some of which could even lead to the plant’s death. Here is a list of issues to keep in mind.

Lack of Water Flow

Compressed soil reduces the flow of water from the top to the roots. Taking a walk in compacted soil is like going for a walk but not being able to go to any new places in your neighborhood.

For a beginner indoor gardener, this can complicate matters considerably. Getting a hang of when to water your houseplant is not easy when you’re a green indoor gardener. When it comes to watering, I always tell people to put a clean finger into the soil to feel how wet it is rather than using a schedule. Dry soil necessitates watering whereas moist soil does not.

Imagine the following scenario. You have been watering your houseplant for months, but it does not look healthy, and the leaves turn yellow. There are drooping leaves that have even turned brown around the edges. The leaves have a crispy texture, and the plant is drooping.

This is the classic case of overwatering, isn’t it? Except that it isn’t. The soil was compacted, making it impossible for the water to reach the plant’s roots.

Overwatering

According to the example above, most new indoor gardeners would make the same mistake when they see their plant is wilting. They would water it more. Their amount of water is clearly not enough, right? That’s what appears to be the case, but it’s not.

However, water is not able to travel freely due to the compacted plant soil, which does not mean it cannot travel at all if they are sufficiently watered. Whatever air pockets there were within the soil have been filled with water.

If you’ve ever been underwater in a swimming pool or the ocean and experienced the feeling of being unable to breathe, you know exactly how frightening that is. Now imagine this would happen to your plant. Plants cannot survive without sufficient oxygen, which is one of their basic requirements for life. They can drown in their pots.

Then you’ve got another problem to contend with: root rot caused by standing water. This condition causes the plant’s roots to rot, thereby killing it up from the ground up.

Now you’re probably wondering if the drainage holes on your plant aren’t functioning properly. The drainage holes are still operational, but the water is not getting to the holes because it is trapped within the compacted soil.

Decreased Aeration

If you have a compacted soil, your houseplant is not getting as much oxygen as it requires even if it does not drown in trapped water. In addition to photosynthesizing and producing oxygen that way, plants are like you and me in that they must breathe. 

That’s not what respiration is. During respiration, a plant breaks down sugar into oxygen and then uses it to maintain itself and grow new parts, including stems, leaves, and flowers.

The plant cannot breathe on sugar alone, so without enough oxygen, it will cease to grow. If these conditions persist for too long, it may not even have enough energy to sustain its own growth.

Limited Nutrients

What will happen when you replenish the soil in your indoor plant with fertilizer? Compressed soil blocks the nutrients from becoming available. Some nutrients might make it through, however they can’t be said in what quantities. They can also get sucked up in the top of the soil, which is far away from the root zone.

Plant life depends on nutrients. Nitrogen is vital in synthesizing enzymes, amino acids, electrolytes, and chlorophyll for plants. Potassium keeps carbohydrates, water, and nutrients flowing consistently through a plant’s tissues. The nutrient also triggers enzyme activity to produce more adenosine triphosphate, or ATP, as well as protein and starch. ATP is particularly important because it influences how frequently a plant photosynthesizes.

Do not believe that I have forgotten phosphorus, as I did not. Phosphorus helps plants to retain their genetic material and allows the flow of nutrients through the plant’s stem. Photosynthesis and energy transfer are dependent on phosphorus.

As people can suffer nutrient deficiencies from poor diets, so too can houseplants. A nitrogen deficiency will result in yellowing, pink or spindly leaves. A deficiency in potassium can lead to chlorosis or yellowing of the leaf margins. This can lead to death for your plants. With a deficiency in phosphorous, your houseplants will turn bluish-green with dull-looking leaves.

Reduced Root Growth

The roots of a plant like to expand and settle in. However, with so many blockages throughout the compacted soil, the roots cannot be moved around much.

As the roots continue to grow because your houseplant is starved of oxygen and thus energy, the roots could spiral around the pot until your houseplant becomes rootbound.

Although it is true that some potted plants actually thrive as rootbound plants, in other cases untangled roots can cause a rootbound plant to die from choking on itself.

That said, in order to give your potted plant the best shot at flourishing, you need to know whether it thrives when it’s contained within a smaller root ball or if it grows better when its roots are spread out.