DRAINAGE DO OR DIE

We have a saying in our office, “You can plant in just abut anything as long as it has drainage.” The reason why drainage is important is that most plants don’t like their roots to sit in water, and without drainage, water build-up in containers is likely.

Why is drainage important?

Although plants use their roots to take in water, too much water will lead to root rot, which kills offthe roots and eventually the plant. Surplus water also results in a lack of air flow around the roots, preventing them from absorbing oxygen, which is also imperative for plants to survive.

The importance of proper potting medium

The type of potting soil used in your container plays the most important role in proper drainage. Some mediums retain more water than others, so it’s important to understand how it works and what will work best for your plants.

The science bit

Without being too technical, when you water a pot plant from above, the water drains through the soil and out the bottom of the pot through drainage holes, thanks to gravity. A good potting medium will include water-retaining materials so that some water is held in place for use by the plant’s roots at a later stage. If your potting soil contains very fine particles and a small proportion of air spaces, the water can ‘wick’ upwards by what is called capillary action. When this upward force is greater than the downward gravity, it creates a ‘perched water table’ at the bottom of the pot that doesn’t drain out. The water sits there and causes the pot to become waterlogged – a death sentence for your precious plant.