Brunnings Horticultural Charcoal 5L – Drainage & Soil Conditioner for Pots, Orchids & Terrariums

Brunnings Horticultural Charcoal 5L: Drainage and Soil Conditioning for Pots and Mixes

Brunnings Horticultural Charcoal is a chunky, lightweight potting medium made largely of carbon, used to improve drainage and "sweeten" soil in pots, mixes and closed plantings. This 5L bag is a soil amendment rather than a fuel charcoal: its job is to open up potting mix, absorb excess moisture and odours, and help control the disease-causing bacteria that build up in wet, stagnant soil.

Its usefulness comes from its porosity. The charcoal is riddled with fine pores, so it holds water and nutrients and releases them back as plants need them, while also creating air pockets that stop mixes compacting and keep oxygen around the roots. That combination, better drainage plus better aeration, is why it's a staple for orchids, epiphytes, terrariums and pots without drainage holes, where soil can otherwise turn sour.

What It Does in the Mix

• Improves drainage and aeration, helping prevent compaction and waterlogging

• Absorbs excess moisture, then releases it back as plants need it

• Holds onto nutrients and reduces leaching during watering

• Sweetens soil and helps control disease-causing bacteria in stagnant conditions

• Absorbs odours, useful in closed pots and terrariums

• Supports root growth and beneficial soil life

Where to Use It

• Pots and tubs: as a drainage layer at the base, or mixed through the potting media

• Orchids and epiphytes: blended with bark or perlite for a chunky, free-draining mix

• Terrariums and closed containers: a layer to keep the environment fresh and prevent soil souring

• Aquariums: can be added to help keep water fresh

• Propagation: as part of a light, well-aerated striking mix

How to Use It

As a general guide, blend it through your soil or potting mix at around 5 to 20%, using more where you want sharper drainage and aeration. For pots and tubs it can go in as a bottom drainage layer or mixed straight into the media. In orchid and aroid mixes, combine it with bark and perlite for a chunky, breathable blend. In terrariums, a charcoal layer helps keep a closed environment clean and odour-free. It's a soil additive used alongside your normal mix rather than a standalone growing medium or fertiliser.

Frequently Asked Questions

What is horticultural charcoal used for?
It's a soil amendment that improves drainage and aeration, absorbs moisture and odours, and helps prevent soil going sour, especially in pots, orchid mixes and terrariums.

How much should I add to my mix?
As a general guide, around 5 to 20% blended through the mix works well, with more where you want sharper drainage.

Is it the same as barbecue charcoal?
No. This is a horticultural grade meant for soil and potting mixes, used to improve drainage and condition soil, not a cooking fuel.

Can I use it in terrariums and pots without drainage holes?
Yes. That's one of its main uses. A charcoal layer helps manage moisture and keeps closed or drainage-free plantings from turning sour.

Does it work for orchids?
Yes. It's widely used in orchid and epiphyte mixes, blended with bark and perlite to create a chunky, free-draining medium.

Where can I buy Brunnings Horticultural Charcoal 5L in Australia?
It's available from BPG Supplies (Bonnyrigg Produce & Garden Supplies), with local pickup in Bonnyrigg NSW and delivery across Australia.