grow medium for indoor plants
Indoor Growing

Getting to Know Grow Mediums for Indoor Plants

Grow mediums are essential for the growth of indoor plants with led grow lights. If you select the right growing medium, you will see the best result.

But there are dozens of growing mediums available that it becomes challenging for beginners to select the right one.

In this article, we will tell you the characteristics of the best growing medium. We will share the factors you need to see. We will also have a look at different growing mediums used for indoor plants.

Let’s start the discussion.

Characteristics of a Good Growing Medium

Everyone would recommend using a good grow medium for indoor plants, but how you would know whether the growing media is good or not. Beginners often get confused while selecting a grow medium for their indoor plants.

If you know the characteristics of good grow mediums, you can easily select the right one according to your needs. Let’s have a look at the characteristics that good growing mediums possess.

Basically, the characteristics can be classified as physical and chemical characteristics. You need to see both of them to understand which growing media is suitable.

Drainage and Aeration:

These two things are the most important for the best grow mediums. Drainage refers to the drain of water from the medium, and aeration means the availability of air to the medium.


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These two factors are interrelated. A good grow medium drains the given water quickly and does not hold excess water.

It is necessary to drain water because the plant medium will not allow the entrance of air without it. As long as there is a bulk quantity of water in the soil, aeration is not possible.

Thus, when the plant drains faster, aeration is improved, and the soil gets enough air according to its needs.

If the water does not drain properly, the plant root will start to rot, and it will harm your plants. In addition, due to excess water, the plant won’t be able to get oxygen and respire as the pores are clogged. This problem is termed waterlogging.

water logging

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In waterlogging, the plant roots cannot respire. It adversely affects the growth of the plant. In general, if the water is logged for a day, the growth of the plant will be reduced by 50%.

Proper drainage and aeration ensure the health of the plant and prevent various problems. In addition, it is also good for growth.

Water-holding Capacity:

The water-holding capacity is another factor to assess the grow mediums. It refers to the water left after the drainage is forced by gravity.

It is good for plants to drain water quickly, but it does not mean that the medium should drain all water.

It must retain some water because plants need it for photosynthesis. It should not dry out so quickly that the plant might suffer from the scarcity of water.

Ideally, the plant should hold moisture, not a bulk amount of water. It is suitable for aeration as well as photosynthesis.

Weight of the Grow Medium:

Grow mediums provide physical support to the plants, which is why they need to be heavy enough to provide support to the plants and hold them properly.

Therefore, bulk density grow mediums are preferred.

The weight of the grow medium should be optimal; it should not be so heavy that it becomes difficult to move them, and it should not be so light that it cannot support the plant.


Growers usually prefer low fertility during the establishment phases, and then they add fertilizers in the growing phase. It helps plants grow better.

Cations Exchange Capacity:

Plants require several mineral nutrients for their growth, and these minerals are provided by grow mediums. These nutrients are usually cations (positively charged, such as Ca+2 and K+).

The grow mediums must absorb these nutrients so that they can provide nutrients to the plant when needed.

Cations Exchange Capacity (CEC) shows the ability of the growing medium to hold these cations.

cations exchange capacity

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If the CEC is high, it will retain the mineral nutrients for a long time, and there won’t be a need for fertilizers often. If the CEC is low, you need to provide fertilizers frequently. Thus, the grow mediums should have High CEC.


The pH of a growing medium is of utmost importance because it determines the availability of nutrients in the grow medium. Some nutrients are available at low pH, while some are available at a high pH.

For instance, Iron is available at low pH levels. Thus, the pH should be in the optimal range so that it could have favorable pH for all the required mineral nutrients.

Types of Indoor Grow Mediums


Soil can be classified into three types: Sand, Silt, and Clay. All these are considered as the soil, and the only difference between them is their physical size.

Clay has the largest particles, Silt is in the middle, and Sand has the smallest particles.

It is the most commonly used grow medium because it is easily available and cheap. It has almost all mineral nutrients required by plants. It is perfect for beginners as they can easily get it at a low cost and experiment with different things.

The larger the particles, the better will be the drainage and aeration, which means clay has the best aeration. Moreover, clay also retains mineral nutrients for a long time.

Keep in mind that the soil is pretty heavy. The weight is excellent for the support of the plant, but it is hard to move the plant. In addition, it is prone to pests and diseases.


Perlite is a volcanic mineral that is obtained through mining. After mining, it is then heated to extreme temperatures. Consequently, the moisture inside the perlite is lost, and there is much space or pores.

Due to the vacant pores and spaces inside perlite, it has a low density and is lightweight. It is light enough that it can float on water. It is easy to carry and move from one place to another.

Most importantly, it can improve the aeration of the grow medium as it can drain water quickly. Therefore, it is often added to other grow mediums.

Another important feature of perlite is that it can absorb water, which can later be used by plants. Simply put, it has a moderate water-holding capacity.

The drawback of perlite is that it needs frequent pH testing and watering.

perlite vs vermiculite

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Vermiculite is also a mineral that occurs naturally. But after mining, it is heated to a very high temperature to create a vermiculite grow medium.

It has the property of expanding on high temperatures. Therefore, its size increases after heating. After that, it becomes a light material that has an excellent capacity to hold water. It also improves the aeration of the grow medium.

Often, vermiculite is used with other grow mediums to improve their drainage and aeration properties. In addition, it has a good ability to supply a few cations, K+ and Mg+2.

Coco Coir:

Coco Coir is a soilless grow medium that is obtained from coconut, which is why it is also known as Coconut Coir. It is usually used as a replacement for peat moss and soil.

coco coir

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The waste coconut husk is used to create coco coir. Surprisingly, it is reusable. If you introduce coco coir to your plants, it will improve the aeration. There is enough oxygen available to the roots. It prevents waterlogging and retains the required water.

The problem with coconut coir is that it does not have the required minerals and nutrients. Therefore, it is necessary to add fertilizer to coconut coir at the start. pH should also be monitored frequently.


Compost is a grow medium that can be grown at home. It is made from food (vegetable and fruit skins) and animal waste (cow dunk). It not only offers an excellent grow medium but also helps in managing waste.

The waste materials are well-rotted, and then they are perfectly ready to be a grow medium.

Due to the presence of organic ingredients, it provides some nutrients to the plants, but it cannot work as a fertilizer. So, you need to introduce fertilizer to the medium when needed.

Most importantly, it is a perfect medium for the growth of beneficial bacteria that prevent pests and improve nutrient breakdown. In addition, it has an excellent water retention capacity.


You might have heard a lot about hydroponics. It is a type of horticulture in which plants are grown without soil. A soilless growing medium is used, and it can be water.

Plants can grow over water. The roots of the plants remain in the water, and the plant floats above it. This grow medium is only suitable for hydroponics.


Sawdust is a waste product when saw cuts wood. It can be obtained for free and is readily available on the market.

It has medium weight and is a good grow medium for plants. It is neither too heavy nor too light, so the plant gets optimal support.

Rockwool Growing Medium:

Rockwool is a hydroponic growing medium. It is made through a mixture of limestone, volcanic rock, and coke. All the materials are mixed and then melted together. It is then converted into fibers, and finally, the fibers are converted into cubes of various sizes.

The pores of the medium are open to offer aeration and provide room for the roots. It is the most used grow medium for hydroponics.

Rockwool can be reused after sterilization. It is available on the market.

The problem with it is the high pH, which refrains the presence of various mineral nutrients. Along with that, the fibers are harmful to humans.

Grow Lights to Ensure Optimal Growth in Grow Mediums

Grow lights are essential for indoor grow rooms as they provide the required radiation to the plants. But choosing the right grow light is also crucial for water retention in the grow medium.

If the temperature of the light is quite high or the light is very near to the plant, it is likely to dry more quickly, and the plant will start to experience the scarcity of water. Therefore, the right grow light is necessary.

There are various types of grow lights available, such as HIDs, fluorescent lamps, incandescent bulbs, and LED lights.

HIDs and incandescent bulbs are not efficient, and they emit a lot of heat energy. The grow medium dries quickly due to the high temperature of the grow area.

When the light falls directly on the grow medium, the temperature increases, and the water starts to evaporate.

Fluorescent bulbs are better than HIDs and incandescent bulbs. They emit less energy and are less expensive.

But the best grow lights for indoor grow rooms are LED grow lights. These are the most efficient grow lights on the market.

LED grow lights convert around 75% of the energy into light. Thus, there is a small amount of energy converted into heat. It does not increase the temperature of the grow area. Consequently, the grow mediums do not dry out quickly.

In addition, LED grow lights are long-lasting, and they have various control options. For instance, Spectrum Y is an efficient LED grow light that has high efficacy, UV and IR bars, and many other features. It ensures optimal growth of your plant in the growing medium.

spectrum y led grow light

Make Your Own Growing Potting Mix

You can make your own potting mix according to your requirements. If you do not wish to buy from markets, you need to know how you can make a potting mix on your own. It is a simple process and works exceptionally well as you customize everything according to your needs.

First, take the container in which you wish to grow your plant. Clean the container using vinegar to sterilize it. Measure the components you want to add to the potting mix.

You can use different proportions of peat moss, soil, perlite, compost, and other growing mediums. After measuring, mix them well in the container.

If there is a need for fertilizer in the first stage, you can also add it according to the requirement. After mixing the component, check the pH level. If it is higher or lower, use pH balancing solutions to achieve the optimal pH range.

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