Cactus Soil Mix

Your new cactus arrived and your wondering what soil mix you should use.

Some of the words you’ll hear a lot of when it comes to cactus mixes are free draining, low organic content and high mineral content.

What does this all mean?  Simply put you need to ensure that whatever soil mix you use for your cactus into it doesn’t hold on to water. 

There are as many soil mixes as there are cactus growers. Many use John Innes 2 as their organic portion. John Innes is like a recipe containing a mix of organic content (usually made up of peat), sand and minerals such as grit however some manufactures use better quality ingredients than others so if you want to use this type of compost this is something to bear in mind.  If you want to help to protect our wonderful planet (we really hope that you do) we don’t recommend using a peat based organic product.  Try substituting for a good quality Peat free soil such as Dalefoots seed compost which is made in the Lake District, UK using Herdiwick sheep wool and bracken or Sylvagrow by Melcourt which uses wood bark and fibres, coir and sterilised loam (composted leaves).  I would recommend adding at least 25% horticultural or silver sand to these before moving onto your next part of the mix. 

The above organic soil/sand mix shouldn’t equal more than 50% of your total mix.

Next, I recommend adding 25% horticultural grit.  Some people use chick flint others use a supermarket brand of cat litter (you will need to ask for the most up to date type to buy on the internet) but essentially any kind of small stone-based product.

Finally add 25% perlite.  If you don’t have or want to buy perlite simply add 50% horticultural. Perlite is a mineral substance that is mined in many countries and is widely used in the horticultural industry.  It is a finite resource so if you can substitute it with an alternative that would be beneficial to the environment.

I have also seen and experimented with growing cactus in pure Mineral substrates such as pumice or volcanic rock and Cactus grow extremely well in these types of substrate so this is a viable option if you are able to purchase it.