Using Outdoor Gardening Soil for Indoor Plants
The top layer of soil in an outdoor garden is known as topsoil, and it is generally about five to ten inches deep, depending on whether the plants are in nature or part of an outdoor garden.
In addition to the numerous microorganisms, and organic matter from compost, topsoil is also rich in air, water, minerals, and organic materials.
Your home container plants surely will benefit from transferring some of the organic garden soil if you have a few outdoor plants that grow well in outdoor soil.
But that’s not the case; these are the reasons why topsoil is a poor choice for houseplants.
Outdoor Gardening Soil is Too Heavy for Indoor Plants
In terms of appearance, the two kinds of soil might seem similar, but they behave very differently. For example, topsoil is much heavier than potting mix.
When it comes to large outdoor plants, heavier soil isn’t a problem, but when it comes to your houseplants, heavier soil will compact on itself.
Aerated soil is better for plants than heavy or compacted soil, as I have been discussing here on the importance of indoor plants for beginners. Compacted soil can be a houseplant’s worst nightmare.
The air pockets that were spread all throughout the soil disappear as the soil hardens and becomes immovable.
Plants require oxygen and water, whether they’re growing outside or indoors. With less aeration, houseplants don’t receive as much oxygen.
Furthermore, compacted soil can prevent water from reaching the plant’s roots, even when you are watering it from the bottom. Soil that is hardened can stop water from reaching the roots even when you are watering from above.
If the soil is heavy and dense, indoor plants may never reach the roots since water is not capable of penetrating the soil.
One of two things will then happen:
- Your roots will not be able to drink the water until it evaporates in the soil.
- Water will accumulate in the roots, preventing them from draining.
The first scenario, where water evaporates before reaching your roots, will cause your plant to look underwatered with symptoms such as wilting, yellowing leaves, and a crispy texture.
During a period of saturated water, your houseplant’s roots may begin to die, which is known as root rot. As long as the roots die, your houseplant will be doomed.
Furthermore, heavy soil can make it difficult for the roots of your houseplant to spread out, which retards its growth. Overall, it’s just a bad situation for your houseplant.
Outdoor Gardening Soil Retains Water for Too Long
When you use outdoor soil, there’s another factor that works against your houseplants. In addition to the compaction of the soil, topsoil has a high water retention rate. This isn’t a problem as long as you’re growing plants like coleus, spider plants, Chinese evergreens, pothos, or philodendrons, which prefer water to survive.
When you use topsoil on your other houseplants that require far less watering, you can expect your plant to get a bad case of root rot much sooner than later.
Earlier I mentioned root rot, but I’ll review it in greater detail now in case you’ve forgotten what it is. Root rot is a result of overwatering or leaving your plants standing water that doesn’t drain.
Plants with healthy roots are white and firm, but when they develop root rot, their roots become black and mushy. An odor will develop around the roots of a plant that has succumbed to root rot, a smell that indicates the houseplant has died.
During this time, your plant’s leaves have turned brown at first. As root rot progresses, your plant’s leaves could turn black. Your leaves will eventually wilt and fall off, as your plant drowns. Growth will halt as a result.
It does not matter if you water your indoor plant frequently and it has never been a problem before, since outdoor soil is naturally moister, root rot will be a certainty for your plant.
Outdoor Gardening Soil Has Less Aeration
Sphagnum moss and peat moss are usually incorporated into indoor potting soil along with vermiculite and perlite for increased nutrition retention.
Also, as a result of its enormous capacity to retain water, vermiculite helps aerate the soil while enhancing nutrient retention. Perlite prevents soil compaction and makes it looser and more breathable.
The topsoil contains none of these ingredients, so it’s naturally less aerated, and outdoor gardening soils are also more compacted, which isn’t ideal for indoor plants.
A few sizes too small for you makes it hard to breathe, isn’t it? You feel a great deal of pressure, right? This is what happens when you have top soil or outdoor soil pressed against the roots of your houseplant.
It cannot complete aerobic respiration, which is the process of taking plant sugars from photosynthesis and converting them to energy, if there is not enough oxygen in the air. In the case of plants with exhausted energy reserves, they cannot devote the resources to new growth, so their growth stagnates. If oxygen levels are especially low, your plants will possibly be unable to sustain themselves.
Outdoor Gardening Soil Doesn’t Necessarily Contain Plant Essential Nutrients
Having mentioned before that topsoil is also rich in compost and microorganisms, I realize I sounded quite promising. Although backlinks indicate outdoor soil is nutrient-rich, is that really true for your houseplant?
As many as 16 plant nutrients exist. Here’s the full list:
- Molybdenum
- Copper
- Boron
- Manganese
- Zinc
- Iron
- Chlorine
- Potassium
- Phosphorus
- Nitrogen
- Hydrogen
- Oxygen
- Carbon
House plants have different needs for nitrogen and other nutrients; some require more nitrogen than others. Actually, all of the nutrients need more nitrogen than others.
So yes, topsoil has lots of nutrients, but if the soil does not have the nutrients the houseplant needs or if its concentration of nutrients is off, bad things will happen. The plant could develop nutritional deficiencies.
Symptoms of nutrient deficiency include burning of leaf edges and tips, browning of leaves, and curly, wilted leaves. The growth of buds and foliage stops; under the surface, roots stop growing.
When you keep your houseplants over-fed in this way, they will suffer from a condition known as fertilizer burn. Their leaves will wilt and turn black or brown. In addition to having a burned appearance, the plant can also become wilted when left too long in the sun.
Why Digging up Your Backyard to Use the Soil for Your Indoor Plants Is a Bad Idea
So you’re not going to use outdoor soil for your indoor plants. That’s fine. But instead you’re planning to dig up a corner of your backyard and soil it in the pot of your houseplant.
In addition, not all soil is created equal. Here are several reasons why you should not dig up your backyard.
Backyard Soil Bad Soil Structure
Besides soil, there’s clay, silt, and sand in your yard, or maybe only some of them. There are plants that favor sand in their soil, such as succulents, but others do not. As for clay, it’s relatively devoid of organic materials and tends to stick to itself well. Therefore, if you have clay in your soil, it won’t drain well.
You are not able to grow plants in the soil in your backyard; it is simply not good enough.
Backyard Soil is Nutritionally Poor
The soil in your backyard, in contrast to topsoil, may not contain nearly as many nutrients and may contain the wrong kinds for your houseplant. Previously, I talked about the detrimental effects a nutrient deficiency can have on your plants. At no time should you put your plants through that.
Backyard Soil Has a Much Higher Risk of Pests
In spite of the fact that your backyard soil may have structural benefits for your plants and contain all the nutrients they require, I still advise against using it. The soil in your yard is unpackaged and does not receive the same quality control standards as the soil from commercial sources.
Keeping a close eye on what you’re digging up will give you a better idea of which pests are hiding beneath the soil. Even if you inspect what you’re digging up closely, few plant pests are visible to the naked eye.
Having an indoor garden will, to some degree, involve pests, but it doesn’t mean you have to invite the insect kingdom into your home or office. It is true that many bugs can kill your houseplant and are more than just annoyances.
Using Backyard Soil Could Spread Disease
The scary thing about soilborne diseases is that even after they infect a victim, they remain dormant in the soil, waiting for their next victim.
You can work with chemicals on the soil to some extent, but this is often an expensive measure. You are better off eliminating the infected soil and starting over from scratch.
If you add a host such as a houseplant to the soil in your yard, you will never know if it contains pathogens that cause soilborne diseases. Let me give you another scary fact: a 2012 journal report from the Journal of the American Board of Family Medicine said that “some bacterial and fungal pathogens have the potential to cause serious human disease not uncommonly found in the primary care setting.” Those diseases? These diseases include those affecting the respiratory tract, the digestive tract, the skin, botulism, anthrax, and tetanus.