From the experts at Soil.Ninja:
 
In the list of beloved thirsty plants, Syngonium tend to run pretty high, but it would be amiss not to mention the hardier species in this genus like Erythrophyllum. This mix caters for all!
 
Using a blend of: Coco Coir Worm Castings, Activated Charcoal, Fine Pumice, Grit, Bark
 
This may seem like an unusually complex mix, but trust us, these components act in a fantastic way of marrying a variety of behaviours that Syngonium utterly desire.
 
Using a heightened amount of activated charcoal means that even if you do air on the side of slightly overwatering your Syngonium (which may not be the worst idea) you are protected against any negative microbial presence. The extra twist of a grit and pumice blend means that during the summer months it drains well and in the winter months there is still enough air in the soil to keep those roots healthy.
 
This blend though catering to the naturally immersed Syngonium does also benefit many other thirsty finer rooted aroids and unlike our allocation mix has a far faster draining action.
 
Thinking of putting something that isn’t a Syngonium? Well, feel free to use this mix on Peperomia & Begonias, both the rhizomatic and cane variety.