When do I fertilise my houseplant?

Houseplants naturally need plant food to develop well. You might be thinking, why do plants need feeding? Isn't the food in the potting soil? That is true, but over time the food in the potting soil runs out, and not every houseplant finds the right food, or all of it, in that soil. This is exactly why you should fertilise your houseplant now and then. It is far from necessary for every plant, and yet even the toughest plants love a feed once in a while!

When to fertilise

It is important to fertilise your houseplant at the right time of year. If you don't, there is a good chance the feed adds nothing at all or even harms the plant's health. The best time to fertilise your houseplant is during the growing period, which runs from March to October. If you have just bought a new green gem, we would advise against fertilising it for the first 2 months. The plant needs that time to settle in, and there is usually still plenty of food in the potting soil.

We strongly advise against fertilising houseplants in winter. During this period the houseplant grows more slowly and often cannot take the feed up properly. Fertilising in winter can even damage the houseplant.

Damage from fertilising

Whether you overfeed or fertilise your houseplant at the wrong time of year, there is a strong chance the plant will suffer. Fertilising houseplants is not a natural process, and some versions contain chemicals. Those chemicals are often acidic and do real damage to the roots. Organic fertiliser can also be very harmful if you use too much of it. Once the roots are damaged the houseplant can grow weak, and the damage can even be bad enough to burn the roots. When that happens, the houseplant is usually beyond saving. It will go limp and its leaves will turn a dull colour.

Types of fertiliser

There are many different kinds of fertiliser, but they fall into three categories: mineral fertilisers, organic fertilisers and a combination of the two.

Mineral fertilisers are better known as artificial fertilisers, although artificial fertiliser also contains various kinds of natural rock.
Organic fertilisers are the most popular type. They contain nutrients drawn from organic products such as chicken manure and cow manure. Organic fertilisers are the same thing as biological fertilisers.
Combination, which is essentially the best of both worlds and therefore very popular. The natural manure is topped up with minerals, which makes it very effective.