The importance of drainage for our plants

If watering is one of the most complicated tasks that every gardener and/or gardening enthusiast has to more or less control so that their plants grow well, the task becomes even more complicated when the substrate or soil does not drain fast enough for the roots to develop properly.

There are some, like succulents, that although they need to be watered with the same frequency as a seasonal plant (2 to 3 times a week), if the growing medium does not have good drainage, it is most likely that they will rot in a short time. weather. How to avoid problems?


  • 1 Floor drainage
    • 1.1 How can it be improved?
      • 1.1.1 Method 1 – Install Drain Pipes
      • 1.1.2 Method 2 – Take advantage of slopes (or create them)
      • 1.1.3 Method 3 – Plant plants above ground level
    • 1.2 Other options – Choose plants that grow in poorly drained soils
  • 2 How to make the drainage in the pots
    • 2.1 How can it be improved?
      • 2.1.1 Method 1 – Mix the growing medium with porous materials
      • 2.1.2 Method 2 – Placing drainage grates
  • 3 Irrigation: what you should know

soil drainage

Before deciding which plants we want to put in a garden, it is very important to check how the soil drains. To do this, you must dig a hole of about 50x50cm, and fill it with water. If after 3-4 days there is still water in the bottom, then it will be necessary to improve it, why? For the mushrooms.

These microorganisms love humid environments, so they will not hesitate for a moment to infect those plants that are weak or sick at any time. And to this we must add that they are very difficult to eradicate , prevention being more advisable than cure.

How can it be improved?

It can be done in two ways: by mixing the soil from the planting hole with perlite, expanded clay balls or any other similar material in equal parts, or by making general changes to the soil in the garden.

Method 1 – Install Drain Pipes

This method is especially suitable for soils that really have a hard time draining water. They are installed as follows:

  1. Draw on the ground the lines where the pipes will be laid. Each lateral ditch has to join the main one at an angle of 60º, and there has to be a distance of about 2 meters between them.
  2. Make ditches about 50cm deep by 40cm wide, on a slight slope.
  3. Put a layer of about 10cm of gravel.
  4. Place the tubes.
  5. Cover with gravel, and put on top of this geotextile fabric. This will prevent dirt from entering and damaging the pipes, but it will allow water to pass through.
  6. Cover with sand.

Method 2 – Take advantage of slopes (or create them)

If the garden has slopes, take advantage of them! And if you don’t have them, you can create them by accumulating more land in one place than in another. Rain and irrigation water can be controlled by raking the ground.

Method 3 – Plant the plants above ground level

And no, it’s not bad. It is a question of creating mounds of earth and planting on them , so that when it is watered, the water will run down the slope and not so much will accumulate around the plant, thus preventing its rotting.

Other Options – Choose plants that grow in poorly drained soils

If you don’t want to complicate yourself too much, you can opt for plants that grow in poorly drained soils . Here is a list of plants that live in a Mediterranean climate, where the soil is limestone and, therefore, where the water does not drain well.

How to make the drainage in the pots


drain grate

Improving the drainage of our pots is much easier and just as important. I often recommend using a universal growing medium mixed with perlite, clay balls or similar because this medium alone can create problems for plants, especially succulents (cacti and succulents), and seedbeds.

How can it be improved?

There are two methods:

Method 1 – Mix the growing medium with porous materials

In nurseries it is becoming easier to find substrates that are already prepared for certain plants. But… (there is always a but), drainage is still, from my point of view, an issue that has yet to be improved. Fortunately, it can be made by mixing it with perlite, clay balls, vermiculite, or even coconut fiber . 

The proportion will vary depending on the type of plant it is. For example:

  • Trees and shrubs: peat-based substrate mixed with 20-30% perlite or similar.
  • Palm trees: peat-based substrate mixed with 30% perlite or similar.
  • Flowering plants (annuals, biennials and perennials): universal growing medium mixed with 20% perlite.
  • Succulents (cacti and succulents): peat-based substrate or mulch with porous material mixed in equal parts, or even add more porous material.

Method 2 – Place Drain Grates

So that the water drains as quickly as possible, drainage grids can be placed (the kind used for bonsai), or even -and it will be cheaper- you can put pieces of plastic mesh with very small holes, or filters of coffee.

Irrigation: what you should know

metallic watering can

Controlling irrigation is essential to prevent plant roots from suffocating. Not all plants need the same amount of water or need to be watered with the same frequency. For this reason, before watering it is important to check the humidity of the substrate or the soil. How? So:

  • You can insert a thin wooden stick – like the ones used in Japanese restaurants – all the way down. If when you take it out it comes out practically clean, it is because the soil in that area is dry. Dip it back elsewhere around the plant to confirm, and only water if it’s really dry.
  • Use a digital moisture meter. You’ll find it for sale at nurseries and garden stores. It can be quite practical, since you only have to enter it and it will tell you the degree of humidity in that area. But, for it to be really useful, you have to insert it in other places around the plant to be sure.
  • If it is in a pot, you can weigh it as soon as you water it, and again after a few days. This way you will know when you should water by the weight it has at each moment.

Another important point is to avoid putting the saucer under the pots , since the water that remains puddled can suffocate its roots. If there is no other choice, make sure to remove the excess water after allowing 10-15 minutes of watering to pass. In this way, your plants can continue to grow normally.

Obregonia denegrii

I hope these tips help you to have beautiful plants and a beautiful garden (or patio)

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