How to Water Plants Properly: Potting Mix, Perlite and Stratum

Watering a plant properly does not simply mean giving it water once a week. How you water a plant depends largely on the substrate it is growing in.

Potting mix, coco-perlite, perlite or Stratum: each one holds and distributes water differently. At Zarits, we grow and sell tropical plants in different substrates, and one question comes up all the time: how do you know when to water and how much water to give?

In this video, I show you the methods we use at Zarits to water our plants and help prevent one of the most common problems with tropical plants: overwatering.

When should you water a plant?

Before even thinking about how much water to use, start by looking at the substrate.

One of the most common mistakes is watering on a fixed schedule: every Sunday, every seven days, and so on. But plants do not always dry out at the same rate.

Temperature, light, humidity, pot size, root system and substrate type can all affect how quickly a plant uses water.

At Zarits, we prefer to check the substrate before watering rather than automatically following a set number of days.

For many of the plants we grow at Zarits in a very airy substrate, we wait until the substrate is quite dry before watering again.

Good to know: watch your plant and its substrate instead of relying only on the calendar.

Some species prefer to stay more consistently moist than others, so the specific needs of your plant should always be taken into account.

My secret for preparing watering water quickly

I do not always have time to collect rainwater or boil water and then wait for it to cool before watering my plants. Over time, I found a much simpler way to prepare my watering water.

I usually fill a container with about 4 litres of water, then add my tap water conditioner according to the recommended dosage. This lets me prepare a larger amount of water at once and have it ready when it is time to water my plants.

It is one of my favourite little tricks for saving time in my plant-care routine. If you use a tap water conditioner, simply make sure to follow the dosage indicated on the product you are using.

How do you water a plant in potting mix?

At Zarits, for plants grown in potting mix or a blend like our coco-perlite potting mix , we especially like using bottom watering.

The method is very simple.

Fill a container or tray with water, then place the pot in the water for approximately 10 to 15 seconds.

At Zarits, the goal is not to completely soak the entire pot. We mainly want the lower portion of the substrate to absorb the water.

Roughly the bottom quarter to half of the pot can become moist.

Then remove the plant from the container and allow any excess water to drain.

Why bottom-water a plant?

Roots naturally grow through the substrate in search of water.

By moistening mainly the lower portion of the pot, you encourage the roots to explore the substrate rather than keeping the surface constantly wet.

This method can also make it easier to control how much water the plant receives.

I find this method especially practical with the smaller tropical plant pots we use at Zarits.

How do you water a plant in perlite or Stratum?

Watering is different when a plant grows in a semi-hydroponic substrate such as horticultural perlite , Stratum or a mixture of the two.

Since these substrates do not behave exactly like traditional potting mix, at Zarits, we keep a small water reservoir at the bottom of the container.

We generally fill approximately the bottom quarter of the pot with water. For this type of growing method, a self-watering hydroponic pot can also make managing the water reservoir easier.

You can even make a small discreet mark on the container so you can easily keep the water level consistent.

Then let the plant use the water in the reservoir. At Zarits, we wait until the water has been used and the substrate has had time to dry before refilling it.

A small pipette can make watering easier

For small containers or plants grown in transparent pots, I like using a pipette or a small watering bottle. It makes it much easier to control exactly how much water you add.

I find it especially useful with perlite and Stratum because you can see the water level directly at the bottom of the pot.

Should you fertilize plants growing in perlite?

Perlite provides very little nutrition for the plant.

Unlike some enriched potting mixes, it mainly acts as a growing medium that supports the roots while providing good aeration and moisture management.

That means you need to make sure the plant receives the nutrients it needs.

At Zarits, we like to add fertilizer approximately every other watering for many plants grown in perlite or other semi-hydroponic substrates.

The concentration and frequency should always be adjusted according to the fertilizer, the plant and its growing season. Always follow the manufacturer's directions to avoid overfertilizing.

Potting mix or perlite: how should you water?

In both cases, the goal is the same: give your plant enough water without keeping its roots constantly in an overly wet environment.

How can you tell if a plant is getting too much water?

A substrate that stays constantly wet can increase the risk of root problems.

Some signs I recommend watching for include:

• yellowing leaves;
• a plant that looks limp even though the substrate is wet;
• substrate that stays wet for a very long time;
• an unusual smell coming from the potting mix;
• brown or mushy roots.

Keep in mind that one yellow leaf does not automatically mean there is a watering problem. An older leaf may simply be reaching the end of its natural life cycle.

I always recommend looking at the overall condition of the plant, its roots and its substrate before drawing a conclusion.

What if your plant is thirsty?

On the other hand, a plant that is too dry may start to lose firmness. Some plants become slightly droopy, while others develop softer leaves.

With experience, you will quickly learn to recognize the signs your own plants give you.

That is exactly why I prefer to focus on observation rather than recommending that every plant be watered exactly every seven or ten days.

My tip: look at the roots and the substrate

One of the best habits I can recommend is simply observing your plant.

Lift the pot. Look at the substrate. Check the moisture level. If the container is transparent, take a look at the roots and the water level too.

The more you get used to checking what is happening inside the pot, the less you will need to water your plants “by feel.”

And trust me: your plants will appreciate it. 🌱💧

---