Substrate for potted plants

For our urban garden or flowerpot to prosper and obtain good results, it is vitally important to correctly choose the most suitable substrate for the needs of each plant that we are going to cultivate (vegetables, aromatic and medicinal, ornamental).

The substrate is very important because it will help, among other things, to make the plants resistant to pests ( aphids , mealybugs , whiteflies snails and slugs , etc.) and diseases ( mildew, powdery mildew, rust ).

We must bear in mind that the substrate is going to be the source of food for the plants  because it will improve the fertility of the soil and must provide them with all the nutrients they need to avoid problems in growth, fruit development, etc.

But in addition, the substrate must provide support to the plant, be able to retain a certain amount of water, allow air circulation and allow the roots to develop and grow well.


Substrate types

We must take into account, in addition to the nutrients it can provide, the texture of the substrate. It should be light and fluffy to allow the roots to breathe so that they can easily obtain nutrients and water. It is best to include a mixture in the pot of several different substrates to take advantage of their characteristics.

Organic substrates

Earthworm humus

It is obtained through vermicompost and is a type of organic substrate that provides a lot of fertility to the earth due to its content of nitrogen, phosphorus, potassium, calcium, magnesium, manganese, iron and sodium. It has a spongy texture and is excellent to improve aeration, it favors the germination of the seeds. As if that were not enough, worm humus inhibits the development of fungi and bacteria that are harmful to plants, making it excellent to use when preparing seedlings and seedbeds. Learn how to make worm castings

Padding or mulch

It is a widely used practice in permaculture and forms the last layer and therefore the most superficial. The mulch in addition to preventing erosion, contributes organic matter to the soil and protects the roots against adverse temperatures (due to excessive cold or heat) and helps to maintain an optimum degree of humidity in the pot. This will help reduce risks and we will save water. Read more about mulching

More articles on organic garden

Inert substrates

Coconut fiber

It is another type of substrate that we can add to the mixture that we prepare to fill the pots and it is suitable for all types of crops. The characteristics of coconut fiber are very interesting: it improves the aeration capacity, the retention of water and nutrients, it reduces the risks of the appearance of fungal diseases, among others.


It is a substrate in granules and its characteristics include the oxygenation of the earth due to its porosity, in addition, perlite is a natural mineral that helps to maintain constant humidity in the pots, it is resistant to erosion and due to the effect exerted by the light on the perlite repels some insects and mites. Reduces the appearance of spontaneous or unwanted plants.


Gravel or gravel (like perlite) due to its characteristics will not provide nutrients or fertility to the land, but its use has some benefits. It is an excellent drainer, so it will help eliminate excess water in the pot and thus prevent rotting of the roots and significant damage to the plants. Also as gravel is porous, it facilitates air circulation in the pot. As gravel we can use the river pebbles.

Are to

It is another substrate that we can use to provide drainage to the plants and avoid caking. The best option is washed river sand and is usually used for its characteristics to make seedbeds in equal parts together with worm castings. For example, an option to prepare a pot would be to first put a layer of sand or gravel, then you can add another layer of coconut fiber, on top of it another layer of worm castings, and lastly the mulch.


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