How to fertilize indoor plants?

Article for :Beginner and plant killerExperienced plant lover

Is your mother-in-law's tongue going grey? Is your heart chain receding? Has your Calathea lost its lustre? Perhaps they need to be fertilized... Less essential than light, watering and repotting, fertilizer nevertheless contributes to the development of houseplants.

Fertilizer, an indispensable source of nutrients

Fertilizerprovides the nutrients essential for healthy plantgrowth. In nature, plants have access to an almost unlimited supply of nutrients. Rain and decomposing organic matter provide them with the food they need to grow, produce new leaves and bloom. When grown in pots and indoors, they can only rely on the elements contained in their potting soil and those provided by water, which is far from sufficient.

Fortunately for all parent plants, it's possible to make up for this shortcoming by fertilizing potted plants. There are several types of fertilizer. Liquid fertilizer is diluted in water. The minerals and trace elements are immediately absorbed by the plant. Solid fertilizers (sticks, powders or granules) are buried in the soil. They release their benefits over several weeks. Finally,foliar fertilizers are sprayed onto the leaf blades.

Foliar fertilizer is sprayed directly onto the leaves

Which houseplants should be fertilized?

All pot-grown plants can be fertilized. Fertilizer requirements vary according to species and growing method.

Do you have an Aglaonema commutatum, a Bird of paradise or a Ficus elastica in your home? It's best to fertilize them. Shrubs, flowering plants and those grown for their foliage thrive best with a little extra. They grow faster, bloom more abundantly and are more resistant to pest attack.

Do you collect sedum burrito, gasteria acinacifolia and echeveria elegans? There's a debate going on. In nature, cacti and succulents grow on very poor soils and receive few nutrients. They grow without fertilizers. But a little help is always welcome, especially indoors. You'll end up with fuller, more vigorous succulents.

When to fertilize houseplants?

Plants should only be fertilized when they are in the growth phase. In the northern hemisphere and indoors, most plants are dormant from October to February, when days are short and light levels are low. You can therefore feed them during the vegetative period, from March to September.

Some epiphytic and semi-epiphytic plants, such as tillandsia racket and phalaenopsis hybrid, require year-round fertilization. They don't feed on their substrate. They draw their nutrients from water and air. Indoors, you'll need to give them additional fertilizer.

Other plants have an inverted cycle, and are in full growth in the depths of winter. If you have cyclamen in bloom in your living room, you'll need to give them fertilizer from November to March.

Conversely, you should never fertilize:

a plant immediately after purchase or repotting. New potting soil contains enough nutrients for four to six weeks, so there's no need to add more.
A plant in poor health. It won't benefit from the nutrients provided by the fertilizer, and will wither even more.

There's no need to count the drops of fertilizer. Just respect the doses indicated on the product.

And don't forget to respect the recommended doses and frequencies. Overdosing can burn your plant's foliage.

Are you afraid you won't get the hang of it? Follow the advice provided by theMonstera application. We'll let you know when the fertilization period begins for each of your plants. We'll also send you a reminder when it's time to top up your fertilizer.

Which fertilizer should I choose?

You need to choose according to the needs of your houseplants. Fertilizers are made up of three main elements:

Nitrogen, whose chemical symbol is N ;
Phosphorus (P);
Potassium (K).

Each has a specific action:

nitrogen nourishes foliage ;
phosphorus promotes flowering and fruiting;
potassium targets the root system.

On labels, you'll find the composition indicated by a combination of the letters NPK and then numbers. These refer to the percentage of each element. For example, a fertilizer graded NPK-535 contains :

5% nitrogen ;
3% phosphorus ;
5% potassium.

This fertilizer is best suited to the care of green plants (foliage and root growth), but is not ideal for flowering plants.

Rest assured, you don't have to be Sheldon Cooper to find the best fertilizer among the hundreds of products available in garden centers and specialty stores! Manufacturers market ranges to suit different types of houseplant. They sell fertilizers for :

green plants, perfect for your Monstera, Alocasia and Pothos ;
flowering plants, for use on your Kalanchoe, Anthurium and Christmas cactus:
cacti and succulents, for your Haworthia, Crassula and euphorbias ;
orchids ;
Tillandisa ;
bonsais ;
..

Once you've found the right reference, it's up to you to find the packaging that best suits your needs. If you're away from home a lot, especially in summer, stick fertilizers will ensure that you're able to spread your fertilizer even during your vacations. If you collect baby plants or have a veritable jungle at home, choose liquid fertilizer. It's easier to dose and less expensive.

Granulated fertilizers allow for gradual release

Types of fertilizer

There are several types of fertilizer. Mineral fertilizers are produced using minerals extracted from the soil or synthetic products. Organic fertilizers, on the other hand, are derived from natural plant matter (plant waste, algae, etc.) or animal matter (ground horn, dried blood, etc.).

Are you looking after your plants and the planet with organic products? You can select fertilizers that meet organic farming standards. But some plant-addicts prefer to make their own mix. If this is your case, share your best recipes and tips with us in the comments section!

By Servane Nemetz
on 10-05-2023 at 07h48