How Indoor Plant Soil Makes The Difference in Houseplant Gardening

Understanding the soil beneath your plants is the key to success if you want to transform your home into a lush, green oasis.

Often overlooked but immensely crucial, suitable soil is the unsung hero of healthy, thriving houseplants. It’s not just about sticking your plant in old dirt and hoping for the best. The soil you choose is the foundation of your plant’s life, providing support, nutrients, and moisture.

Whether you’re a seasoned plant expert or just starting your indoor garden journey, this guide will help you understand the benefits of using indoor plant soil. From succulents requiring well-draining soil to tropical plants needing moisture-rich loam, each plant will require soil to meet its needs.

Plus, we’ll evaluate the importance of soil additives, whether purchasing ready-mixed indoor potting soil or making your own. To finish, we’ll discuss the advantages of using pot soil covers to add finishing touches to your indoor planting.

The Right Soil for Indoor Plants: A Key to Gardening Success

Houseplants generally originate from different parts of the world. Therefore, creating a growing environment within your home that mimics the place of origin is essential. Considerations to take into account include nutrition, humidity, temperature, shade and light, and soil that will enhance these growing conditions.

Why Soil Matters

Potting soil, specially formulated for indoor plants, is a primary system that supports and protects the root structure of your plants. 

But that’s not all.

Soil is the provider for your plants. It has nutrients, air, and water – all the requirements plants need to grow strong and healthy.

Different Plants, Different Soils

As previously explained, creating an environment that matches the natural habits of your plants will encourage successful growth, as a plant struggling in an alien environment will most likely not survive. For example, cacti originate from areas with dry, ffast-draining sandy soil and Prayer Plants from humid rain forests.  Although both plants can be grown in the same household and positioned according to individual requirements, the starting point for both types of plants will be the soil. Both cacti and prayer plants require free-draining soil, but the cacti need to dry out slightly before watering, and prayer plants need to be watered before the roots dry out.  Therefore, it is the added ingredients and the composition of the soil that are crucial to consider when growing your plants.

Key Ingredients in Soil 

Soil in the outdoor garden is generally made up of sand, silt, clay and composted matter. Sand helps water drain fast. Silt is like a tiny sponge that holds water and nutrients. Clay also retains water and nutrients, which can make the soil heavy. Composted matter contains nutrients and is the holding agent.  If garden soil is used for indoor growing, your plants are unlikely to have the ideal nutrients and composition needed to survive and might also have to compete with any seeds that germinate or pests contained in the soil.

Potting soil for indoor plants comprises the following: peat, a mixture of decayed vegetation or the alternative,  more environmentally friendly, coconut fibre;  perlite, small white grains of volcanic rock; vermiculite, a naturally occurring mineral of magnesium-aluminum-iron-silicate with a neutral pH. These ingredients are then combined with compost. This purpose-mixed indoor potting soil is suitable for a wide variety of house plants but can also be adapted to meet the needs of specialist plants.

Checking the Soil Before You Buy

Understanding the growing requirements of your indoor plants will help you purchase suitable potting soil to meet their requirements. Check labels on both plants and bought soil.

Why the Right Soil Makes a Difference

Choosing suitable soil means your plants will grow stronger and healthier. They’ll get the right amount of water, air, and food. Healthy plants are less likely to succumb to the risks of pests and diseases, giving your plant a good start in life.

Factors to Consider when Choosing Indoor Plant Soil

Some plants thrive best when grown in a more acidic soil, so choosing an ericaceous soil is essential. In general, though, a multi-purpose indoor potting soil is the best choice, but always check guidelines on plant labels.

Type of Plants and Their Specific Soil Requirements

In general, whether commercial or homemade,  ready-mixed indoor potting soil will meet the requirements of most plants. However, the following will benefit from specialized potting soil.

• Succulents and Cacti: They need soil that dries quickly and contains a higher percentage of sand and perlite. Look for specific potting soil labelled for cacti or succulents.
• Tropical Plants: Need to retain some moisture around the roots. Soil for tropical plants should hold moisture without becoming water-logged.
• Orchids: These unique plants need soil with lots of air circulation and will thrive in orchid-specific soil.
• Bonsai: Require soil that drains freely without allowing the roots to dry out.
• Citrus Trees: Thrive in a well-draining soil rich in organic matter

Drainage Capacity and Water Retention Capabilities

The key here is balance. Good soil will comprise a formular that supports the root system in the pot but allows excess water to drain away so the roots don’t drown. If the soil is too dense, it will hold onto water, and roots could rot. If it is too loose, water runs through, allowing the roots to dry out.

Nutrient Content and Organic Matter Percentage

To grow, plants will absorb nutrients from the soil. Good indoor plant soil will comprise a balanced mix of peat, bark, and compost. These ingredients contain essential nutrients and help the soil maintain adequate moisture.

pH Level Suitability

 Plants have pH preferences (the scale measuring if something is acidic or alkaline) —most houseplants like soil that’s slightly acidic to neutral, pH 6-7. If unsure, you can test the soil’s pH with an easy-to-use testing kit purchased at your garden store or online.

Compatibility with Different Potting Materials

The pot you choose can affect the soil, too. For example, clay pots absorb water, so the soil in these pots dries faster. Plastic pots hold moisture, preventing water from draining away.

Understanding Different Types of Indoor Plant Soils

A vast selection of indoor potting soils to cater to the needs of all types of plants, from orchids to marantas, are available in garden stores and online. All are designed to meet your indoor gardening needs, from nutrition to composition and correct drainage. Check the plant labels and match them to the soil accordingly.

All-Purpose Indoor Potting Mix

Your go-to soil for most indoor plants, indoor potting mix is formulated to hold just the right amount of water and air. It usually has four essential ingredients: decayed matter, perlite, vermiculite and compost. These ingredients keep the soil light with a crumbly texture. This soil is perfect for pothos, spider plants, peace lilies and many more.

Succulent and Cactus Potting Mix

Succulents and cacti don’t need much water. This soil is formulated with sand and fine gravel and allows water to drain away efficiently.

Orchid Potting Mix

Orchids are like the divas of the plant world. They need special care. Orchid potting mix is different because it consists of bark chunks, charcoal, and sometimes sponge-like materials. This mix doesn’t hold water like regular soil. It allows air to flow around the orchid’s roots, perfect for these lovely plants.

Bonsai Potting Mix

Bonsai trees are like miniature tree masterpieces. Their soil is a unique blend, too. Bonsai potting mix usually has akadama (a special clay), pumice, and lava rock. This mix drains well but also holds enough moisture. It’s perfect for bonsai trees, supporting their unique root system in a limited space.

Citrus Potting Mix

A specific citrus potting mix is vital for lemon, orange, or lime trees. This soil is designed to hold more water than a succulent mix but drains better than a regular indoor mix. It often has added nutrients like iron and magnesium. These are vitamins for your citrus trees, helping them grow healthy and produce fruit.

What Should I Add To My Potting Mix? 

In general, commercially bought, all-purpose indoor potting soil will already compromise a professionally mixed blend of ingredients to meet the needs of your plants, so there will be no need to add any more to the mix; simply open the bag and start potting up. Once a year, it is advisable to top-dress your pot with fresh potting soil to maintain the structure and add nutrients.  Then, every two to three years, depending on growth, repot your plant to replenish used-up nutrients.  

However, if tempted to make your own ready-mixed potting soil, blending the right ingredients can make a big difference in the health and growth of your plants.  Listed are some common additives and their benefits:

• Perlite: This lightweight volcanic rock helps improve drainage and airflow in the soil. It’s excellent for preventing soil compaction, especially for potted plants.
• Vermiculite: Similar to perlite, vermiculite helps with water retention and aeration. It’s better at holding water than perlite, so it’s a good choice for plants needing more moisture.
• Peat Moss: Peat moss helps retain moisture in the soil and adds some acidity, which some plants prefer. However, it is becoming less commonly used in many commercial potting mixes as it is not considered sustainable. Other alternatives, such as coconut coir, are generally promoted as a preferred choice.
• Compost: This is decayed plant matter. Added to your potting mix is a great way to introduce organic matter and nutrients. It improves soil structure, helps with moisture retention, and provides a slow release of nutrients to your plants.
• Coconut Coir: A sustainable alternative to peat moss, coconut coir comes from the husks of coconuts. It helps with moisture retention and provides a suitable environment for root growth.
• Sand: If plants prefer dry conditions (like succulents or cacti), adding sand to your potting mix can improve drainage and mimic their natural growing conditions.
• Bark Chips: These are often used in orchid mixes, providing good aeration and drainage for the roots.
• Worm Castings: This is an excellent source of nutrients. Worm castings are a natural fertilizer and can help improve soil structure and moisture retention.
• Lime: If your potting mix is too acidic, adding lime can help balance the pH, which is especially important for plants that prefer neutral or alkaline soil.
• Fertilizer: While not adding bulk or texture to your soil, incorporating a slow-release fertilizer into your potting mix can give your plants essential nutrients over an extended period of time.

Soil Covers for Indoor Plants

Soil covers or mulch for indoor plants are more than just about making your pots attractive. They play many beneficial roles in the care of your plants. 

So, let’s understand why and how to use soil covers for your indoor garden.

What are Soil Covers?

Soil covers are materials spread over the top of the soil in your plant pots and are usually made from moss, coco coir matting, bark, stones, or even decorative glass. Each type of cover has its benefits.

Why Use Soil Covers?

Moisture Control: Soil covers applied on top of the compost and around the base of the plant will help keep the soil moist by reducing water evaporation, meaning you don’t have to water your plants so often. Choosing a glass dome covering will benefit plants that require extra humidity.

• Weed Prevention: While less common indoors, soil covers will prevent weeds from germinating in potted plants.
• Temperature Regulation: Soil covers can keep the soil temperature more stable. Great for plants that don’t like sudden environmental changes.
• Looks Good: Soil covers can make your plant pots look super stylish, giving your indoor garden a clean, finished look.

Types of Soil Covers

• Moss: Moss, like sphagnum or sheet moss, gives a lush, green look. It’s excellent for moisture-loving plants.
• Bark Chips: These are perfect for a natural, earthy vibe. They’re suitable for plants like orchids and marantas, which prefer excellent airflow around the soil.
• Decorative Stones or Pebbles: Stones are great for a modern, clean look. They’re suitable for plants that prefer dry soil, like succulents and cacti, because they reduce moisture.
• Glass Beads or Marbles: If you want something more decorative, glass beads or marbles add a touch of ‘bling.’ They’re more about looks than function but still help with moisture control.
• Coco Coir: This is a bit like moss and helps to retain moisture in the soil. It’s also a sustainable choice for a natural look.

How to Apply Soil Covers

Applying soil covers is easy. Just spread a thin layer of your preferred material  (about an inch or so) on top of the soil in your pot.

Caring for Soil Covers

Every now and then, check under your soil cover to make sure the soil isn’t too wet or too dry. Over time, organic covers like moss or bark might break down. If they do, just replace them with a fresh layer.

Final Words

Understanding and choosing the correct soil for indoor plants is crucial for their growth and health. Just as we need a comfortable and suitable environment to thrive, so do our plants.

Each type of potting soil, whether for common houseplants or succulents, tropical plants, orchids, bonsai, or citrus trees, is tailored to meet specific needs, from moisture control to nutrient content. Additives like perlite, vermiculite, and compost will enhance your potting mix, catering to each plant’s unique requirements.

Additionally, soil covers add aesthetic value to your indoor garden and play a functional role in moisture retention and temperature regulation.

By paying attention to these details, you can create a thriving indoor garden that brings life and beauty to your space. Remember, ideal soil and care can make all the difference to the success of indoor houseplant gardening.