How to water plants in space


In addition to the right lighting, the right watering is most important for the health of your plant. Here you can find out what you should be aware of. If you are new to houseplants, it will take time until you have a routine and can estimate how to water. But we can say from our own experience: With a little time, watering, and thus plant care, becomes routine and very intuitive.

The tips at a glance:

  1. For most plants, you should always let the soil dry out slightly before watering again.
  2. With succulents, you can let the soil dry out almost completely.
  3. Pour so that the water runs out at the bottom and check that there is no more water on the bottom of the pot.
  4. Use rain or aquarium water on sensitive plants. For most plants, however, stale tap water can also be used if the soil is flushed regularly.

How often do I have to water?

The ironic thing is that most plants don't die from too little watering, but from overwatering. We'll explain why this is so later. First of all, it is important to know that different plants have different water requirements. A plant's water consumption depends on many factors:

What kind of plant is it? Thin leaves with a lot of surface (such as calathea, single leaf, many philodendrons, ferns ...) indicate high water consumption, while thick or wax-coated leaves (such as succulents, cacti, even some orchids ...) indicate low water consumption. Plants with thick leaves can store water themselves and can sometimes get by without watering them for a longer period of time, whereas thin-leaved plants dry out quickly as soon as the soil is dry.

It is also crucial in which soil the plant is located. It depends on how much water can be stored in it. Pure coconut soil or peat soil, in which plants are often grown and sold, stores a lot of water. If something like pearlite or pumice is added to the earth (inorganic components that absorb little or no water and aerate the earth), it can store less water. A plant in peat therefore has to be watered less often than the same plant in succulent soil (where less water-storing components are added).

The light also influences water consumption. More light means more photosynthesis and therefore more evaporation. The warmth of sunlight also increases the temperature, which lowers the relative humidity, which also causes more water to evaporate. Of course, with more light, growth also increases, which also increases water consumption.

How often do you have to water now? As you may have noticed yourself, one cannot really assume a fixed rule of thumb like "once a week". Instead, you need to monitor your plants and respond to their individual needs. We water our plants like this:

We let the soil of succulents (plants that can store water) dry out almost completely. Only then do we pour again. By the way, you can use the weight of the pot to estimate how much water is still stored in the earth. With a little experience, it works really well and quickly 🙂

We let plants that use more water dry about 1-3 cm. This means that we use our fingers to feel whether the first 1-3 cm of the earth is dry. Only then do we pour. As long as the lower layers of the earth are still moist, the plant gets enough water. Of course there are always exceptions: the notorious maidenhair fern always wants to be completely wet, including the surface of the earth. But for most plants, this rule works very well. Here, too, with a little experience, you can only determine whether you should water or not by lifting the pot. Rule of thumb: If you're not sure whether to water, it is better not to water.

Why do I have to let the soil dry out slightly?

You may be wondering why does the earth have to dry up in the first place? Can't I keep it wet all the time when the plant roots need water?

And you're right, plant roots need water. However, they also need oxygen! Just like the leaves, roots breathe, only underground. If the earth is always saturated with water, the roots cannot breathe and can die and go moldy. (Short excursus: Plants that have their roots in water get their oxygen from the water, but anatomically they form different roots than plants in soil!)

It is therefore important to let the soil dry out again and again so that the roots can breathe. It also solves another problem: fungus gnats. They lay their eggs in the upper layers of the earth. They need constant moisture, so you can counteract them effectively if you always allow the soil to dry out slightly.

There are substrates that are so coarse that the roots are always in contact with the air, no matter how moist the substrate is. These substrates can be watered as often as you like and the plants stay healthy. We will go into this in more detail in the topic of substrate!

How do I have to water?

For newbies we recommend watering like this: Bring the plant to the sink or hold it over a bucket and water it completely so that the water runs out of the holes at the bottom of the pot. Make sure that no part of the earth stays dry. Do not put the plant back in the planter until the soil is no longer dripping. Watering like this has several advantages: You prevent the plant from sitting in water. Something like that can easily drown the roots in this area. In addition, you regularly flush minerals such as fertilizer and especially lime out of the earth.

Some plants are in old or poor soil. Many plants are sold in peat. However, peat quickly becomes hydrophobic, the irrigation water simply rolls to the side and the earth is not moistened. When you find out, you know it's time to repot. Read the topic of substrate. To water the plant anyway, make a few holes in the soil, for example with chopsticks.

How do you water plants from below?

Perhaps you have already heard the advice of certain plants to water from below. But how does it even work and which plants benefit from it? To pour from below, fill a saucer one to two centimeters high with water and wait around twenty minutes. This allows the plant to absorb as much water as it needs and the surface remains dry. This also helps against fungus gnats. You can find more measures against the annoying little flies and other pests here.

Which plants should you water from below?

Some houseplants don't like water on their leaves. These include succulents, begonias, cyclamen, bobbed heads, orchids and African violets. Succulents in particular often fill the entire flower pot, making it difficult not to wet the leaves when watering. If drops of water remain on the leaves, the succulent can rot. If you water succulent hanging plants such as String of Pearls or String of Turtels from above, the sensitive plant strands can suffer if the surface of the earth remains wet for too long. Basically, you can water all plants from below.

What do I have to pour with?

Plant roots get water from the earth through a process of osmosis means: The root cell membrane is permeable for water. The water diffuses from an area with a low concentration of minerals to the area with a high density of minerals. Normally the mineral content is higher in the root, so the water from the earth is drawn into the root.

What happens now when the concentration of minerals in the earth increases? Water diffuses less and less into the roots. The result is brown leaf tips, weak plants and, in extreme cases, death. Calcareous water and fertilizers are the main reasons for a soil that is too mineral-rich. Therefore, ideally, you should not fertilize too much, ideally take rainwater and rinse the earth regularly.

Of course, this is not necessary for every plant, especially if you flush every now and then. But if you have brown leaf tips, you now know what it could be (besides low humidity). We water most of the plants with the chalky Karlsruhe tap water. Rainwater is only given to sensitive plants such as orchids.

What about self-watering like hydroponics or Lechuza ™?

You can find out more about this in the Substrate section.