What You Need to Know About Potting Mix

A good quality potting mix is essential for happy potted plants. These days, many people live in urban dwellings without a backyard or garden space, so they rely on plants grown in pots to satisfy their garden needs. Indoor pot plants have also experienced a boom since the COVID pandemic began, with people wanting to bring nature inside when unable to go outside.

Before you get busy with pot plants, take note of the important facts you need to know about potting mix so your pot plants can thrive. So, today, we’re going to take a quick look at some must-know facts about potting mix!

What is the Best Potting Soil?
Potting mix sales have significantly increased in recent years, with many different types now on the market. However, always choose a good quality potting mix as they contain the right blend of materials to enable the pot to drain freely. The potting mix should be clean and free of insects and pathogens. Contaminated potting soil can be identified by a sour smell.

Can I Use Soil From Outside as Potting Mix?
The short answer is NO, pot plants require a medium that is more free draining and sterile. Potting mixes are a blend of sphagnum moss, bark, perlite, vermiculite, and compost (some may also have inorganic chemical fertilisers). Interestingly they do not contain soil.

How Often Should I Fertilise Pot Plants?
Pot plants need to be given a boost with a natural fertiliser such as Food2Soil at least every quarter per year. You can also use a slow-release organic fertiliser but is it not necessary. Best practice is to observe and monitor your plant’s growth; a rule of thumb is that if your plant is growing quickly it will need more nutrients.

How Long Does Potting Mix last?
Even the best potting mix is only good for a couple of years, once it starts to break down it will no longer drain effectively. So, repot your plants every 2-3 years with a new potting mix to keep your plants healthy and thriving. At this time, you may need a larger pot depending on the plant.

Proper Watering
It is always a good idea to test if a plant needs watering before you get too generous with the watering can. One way is to dip your finger (at least 1 inch or more deep) into the top layer of potting mix to test if it is wet/dry. You can also get a soil moisture testing probe from your local nursery/hardware store to assist.

Proper Drainage
All potting containers should have holes at the bottom for drainage, and the container should sit on a removable saucer. Place pebbles, rocks or broken crockery to help improve drainage and prevent soil from clogging the holes. It is a good idea to check the holes periodically to make sure they aren’t blocked.

Can I Reuse Potting Mix?
Yes, you can reuse potting mix, but you will need to feed it before you do. By that we mean, mix it with fresh compost mix, manure and Food2Soil biological fertiliser. Ensure the soil is aerated and light, if it is too dense you may need to add perlite or sand to allow for better drainage. Then apply monthly Food2Soil applications, especially in the growing season to ensure the potting soil has the nutrients required for plant growth. However, if the potting mix shows signs of mould it is time to send it to the compost heap!

What is the White Mould on the Dirt of Potted Plants?
The white mould found on the surface of indoor pot plants is usually harmless. The strain, known as saprophytic fungus, often occurs from over-watering, poor drainage, damp conditions, and old or contaminated potting soil. The fungus feeds on decaying organic matter in soggy soil. Left untreated can lead to root rot.

How to Fix Hydrophobic Pot Plant Soil?
Hydrophobic soil repels water. It is where large particles of soil get coated in waxes which means water skims off the top and down the sides. Often occurs in potted plants.

Using organic matter and mulches to keep the soil moist is a good way to prevent the soil from becoming hydrophobic. However good remedy for pot plants is:

Get a large tub of water and add a 1 x capful of wetting agent and 1 x capful of natural plant food (like Food2Soil organic fertiliser, fish emulsion or seaweed). then dunk the whole plant (pot included) into the water. Let all the bubbles rise, keep the pot in the water for about 20-30 seconds and leave to drain. This will replenish the soil and fertilise the plant at the same time.

Is Potting Soil Toxic to Humans?
Though unlikely, it is important to note potting mix can be harmful to some people. Potting mix can carry harmful bacteria and fungi, causing Legionnaires Disease. Legionnaire disease is a type of lung infection caused by inhaling or ingesting dust particles from contaminated soil.

Potting mix is usually a mix of inorganic and organic material. It is often stored at higher temperatures than soil and retains heat longer, which means bacteria and fungi can grow and reach problematic numbers, especially when kept in moist and warm environments. When working with potting mix, using personal hygiene is advised (washing hands, wearing gloves) and wearing a mask if you are susceptible to lung conditions or have weakened immunity.

Pot plants are so handy and really do make gardening accessible to everyone, from a tiny pot to a large wine barrel. We have plants in all kinds of make-do pots including old wine coolers and old kitchen pans. As long as you follow the tips above the options are endless.


Preparing your potting mix can be slightly overwhelming when you first start looking into it, but as long as you do what you can to make a positive environment for your plant life, you’re sure to reap the rewards. To learn more, explore our blog, and check out the Food2Soil biological fertiliser range today.