How to Choose the Best Indoor Plant Food
Indoor plants are limited by the compost in their pots, so it’s really important to water and feed them regularly. Healthy plants need regular fertiliser in the growing season to look their best.
Here’s how to choose the best indoor plant food
Look For a General Purpose Fertiliser
For the majority of leafy and flowering indoor plants, a general-purpose fertiliser will do a good job. Exceptions are orchids, cacti and herbs who tend to thrive in poorer conditions and need less fertiliser than a peace lily for example.
A good general-purpose plant food will contain the following nutrients:
Nitrogen (N): good for leafy growth
Phosphorus (P): to strengthen roots
Potassium (K): to boost flowers and fruits
If your general-purpose fertiliser includes all three of these basic nutrients it’ll do a good job. Other ingredients such as clay or limescale are included to prevent chemical burns on the roots.
What Do The Numbers Mean On Indoor Plant Food?
Fertiliser numbers are ratios that indicate how much of each nutrient is included.
6-12-6 for example indicates 6% nitrogen, 12% phosphorus, and 6% potassium.
Indoor fruits such as tomatoes will have a higher percentage of potassium (sometimes called potash) which should be applied when the flowers appear to boost fruit production.
A general-purpose indoor plant food will have a roughly equal amount, but sometimes there will be more phosphorus to boost root growth, or nitrogen to help with leafy growth.
Do I Need A Specific Plant Food?
Many companies offer specific fertiliser for certain plants. Orchids for example need much less food than leafy greenery so specific orchid foods are available to help growers out. The same goes for citrus plants, cacti – who need barely any fertiliser – and herbs.
If you’re growing crops, like indoor tomatoes, that you intend to eat, make sure the fertiliser is suitable for this. You’ll want to look for an organic or plant-based fertiliser that is suitable for use with edible crops.
Is Liquid or Granular or Solid Plant Food Best?
Plant food is available in several different forms. They all work effectively, it just depends which type will best suit you and your plant-feeding routine.
If you don’t want to think about adding fertiliser every time you water your plants, a solid or granular formula may be most suitable. These are generally long lasting and they release nutrients slowly. As a result, you can water as normal once they’re in place. You just need to remember when to reapply them – it can be easy to forget when you only have to do this every two months or so.
Liquid plant foods usually need weekly or fortnightly applications, which will probably fit in well with your existing watering schedule. This is a good way to apply plant food if you feel like a regular routine will suit you best.
Liquid fertilisers are generally fast-acting too, so if your plant is looking a bit unwell, liquid plant will be your best option to help it recover. Just don’t go overboard – only ever use the recommended amount, as too much will poison your plant.
If you’re still wondering what’s best, our FAQs below might help.
Indoor Plant Food FAQs
What is the best food for potted plants?
Leafy green houseplants usually benefit from general-purpose houseplant food in liquid, granular or solid form. A slightly higher amount of nitrogen can give a boost to leaves, so this might be a good choice if they’re going yellow.
As we’ve already mentioned, certain plants will have different food requirements. For example, if it’s an orchid, herb or citrus plant, you should consider a plant food that is intended for the specific species.
Be sure to follow all fertiliser instructions carefully and avoid getting fertiliser on foliage – this will burn and leave scorch marks.
Are coffee grounds good for houseplants?
No, coffee grounds don’t add anything useful to houseplant soil other than bulking it up for more root space. If you want your plant to thrive, a plant food with nitrogen, phosphorus and potassium in the correct ratio is your best bet.
If in doubt, choose a general-purpose indoor plant food.
How often should I fertilise indoor plants?
Plants only need fertiliser in the growing season which is most often spring to summer. This is because they tend to go dormant in the winter months, although there are some exceptions like orchids!
How often you should feed your plants is directed on the plant food packaging. Liquid forms are usually required every one-to-two weeks, whereas granular and solid food lasts for several months. You can also buy drip feed and slow-release plant foods that last 3 months.
Be careful not to over-feed your houseplants. Overfeeding creates yellow leaves and most often your plant won’t recover. Mark feeding day on the calendar, or set an alarm, and stick to the routine!