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Soil with a high moisture retention for a Calathea Soil with a high moisture retention for a Calathea

How to make your soil retain more water?

Some plants love moisture and love to be in soil that keeps them moist at all times. This sounds like quite an easy thing to do: just water your plants more often. This works really well in the short term, but isn't a great long-term solution. What if you go on vacation and you can't water your plant for 2 weeks? How do you make sure your soil is moist without attracting pests or overwatering your plant?

In this plant care guide, we're going to look at how we can improve our soil and hold more moisture. We'll also explain why simply watering your plant more often isn't a great long-term solution. There are much better, more sustainable ways that will make your plant happy and help it thrive.

These are the things we're going to look at:

Let's get into the reason why watering more often isn't a long-term solution for your moisture-loving plants.

Why is watering more often not a long-term solution?

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Watering a plant

Watering your plant more often to give it more moisture isn't a good long-term solution. But why not? Here are 3 reasons:

  1. Your plant relies on you
  2. Soil compacts over time
  3. Accidentally overwatering

1. Your plant relies on you

When you water your plant more often and that's the only way your plant gets enough moisture, it relies on you being there. If you, for any reason, can't water your plant for more than a week at a time, your plant will dry out and die. You can't go on vacation without having to worry about your plants dying while you're away. That's something all plant owners have worried about at some point, but it doesn't have to be that way any more.

2. Soil compacts over time

Another reason watering more often isn't a great way to keep your plant healthy is the fact that soil compacts over time. When you water your plant often, the soil will compact and become dense.

Most houseplants don't do very well in dense soil, because it doesn't allow as much oxygen to get to your plant's roots. When your plant's roots don't get enough oxygen, it might cause root rot. Dense soil also doesn't drain the excess moisture away very well. This is the perfect place for fungi to grow.

3. Accidentally overwatering

When you water your plants more often, you could accidentally overwater it. Plants don't respond to watering issues right away; it takes them a few days. If you accidentally misread your plant and water it more than you should have, you're at risk of overwatering your plant.

If you can extend the time between watering, you run a much lower chance of making mistakes. You can see how your plant responds over a few days and see if you need to change your plant care.

How to make the perfect soil for moisture-loving plants?

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Moisture retaining soil

Simply watering your plants more often doesn't work in the long term, but what does? There are many great ways to help your soil retain more moisture, while keeping your plant happy.

First, we'll need to determine what the perfect soil for moisture-loving plants is and does. The perfect soil for your moisture-loving plants should:

  • Keep the soil moist for multiple days
  • Keep it's structure to prevent the soil from becoming compact
  • Let excess water drain away quickly

This soil will stay the right moisture level for your plants, without overwatering it. This soil will also make sure plenty of oxygen can reach your plant's roots. But talk is cheap, lets see how we can do this!

The ingredients

In this section, we're going to look at which ingredients you'll need for your soil. By adding these ingredients, your soil holds onto moisture for longer, without risking the health of your plant.

You'll need these any one of these ingredients to retain more moisture:

  • Vermiculite
  • Sphagnum (peat) moss
  • Coconut coir

You don't have to use all 3 ingredients. Using 1 or 2 of these ingredients is enough for your soil.

You'll also want to add ingredients to improve drainage, any one of these is great:

  • Perlite
  • Leca
  • Grainy sand

Now, we'll look at what each of these things are and how it can help you to retain more moisture in your soil. Afterwards, you'll be able to choose which one you want to use.

What is Vermiculite and how can you use it?

Vermiculite

Vermiculite is a naturally occurring mineral that's heated until it expands and forms into lightweight particles. It's a material that's naturally resistant to mold and other diseases and can hold a lot of moisture. It's sterile, non-toxic and will never go bad. This means that it's great for long-term use with your moisture-loving plants.

You can use this with your soil by mixing it in, just like you would with Perlite. It's quite cheap and you can find it at almost all gardening centers, or through a link at the bottom of this post. Vermiculite is not a natural growing medium for plants, so it also doesn't contain any nutrients to help your plants grow. You'll need to add these nutrients through soil and fertilizer.

Vermiculite retains a lot of water, so when you're mixing this with soil, be sure to not add too much of it. A good measurement is 1/6 Vermiculite, 2/6 leca/perlite/sand, and 3/6 soil.

Advantages: Sterile, resistant to mold, doesn't go bad

Sphagnum moss (and peat moss)

Sphagnum moss Photo by ali amani on Unsplash

Sphagnum moss and Peat moss are both the same type of moss: both are dead and dry. The only difference between the two is the way they're collected. Peat moss is collected as dead moss from the ground and Sphagnum moss is collected as live plants and then dried.

If you have a plant that's fine with more acidic soil, you can use peat moss to retain extra moisture in your soil. But if your plant needs more neutral soil, adding Sphagnum moss adds the water retention properties you need.

You can use both of these types of moss by mixing it in with the soil. The chunks of moss will retain moisture quite easily, while also giving the soil some structure. This helps to prevent compacting soil. Moss is a natural product, so it does contain a few nutrients to help your plants grow. Most of the nutrients will come in through the soil and any fertilizer though.

If you want to use Sphagnum moss in your soil, you can add about 1/3 moss, 1/3 soil, and 1/3 leca/perlite/sand.

Advantages: Anti-bacterial, anti-fungal properties, pH neutral

Coconut coir

Coconut shells Photo by Diomari Madulara on Unsplash

Coconut coir is a "waste product" of coconuts. Coconut coir is a great addition to you soil if you're looking to improve the water retention. When you add this to your soil, you're adding fibers to improve the structure of your soil. The fibers keeps each other in place quite well, so that will help to prevent your soil from compacting.

Besides these very practical advantages, coconut coir also protects your soil and plant against diseases. It's a clean product that improves the water retention, without attracting mold.

Like Vermiculite, Coconut coir itself doesn't contain any nutrients for your plants. This means that you'll have to add it to something that does, like soil.

If you're going to use coconut coir to improve the water retention of your soil, you'll need to add perlite, sand, or Leca to improve drainage. The coir doesn't drain well and could cause problems if you don't add enough drainage.

As a rule of thumb, use 1/3 soil, 1/3 coconut coir, and 1/3 perlite/leca/sand.

Advantages: Protection against diseases, optimal pH level for nutrient intake

Excellent drainage for moisture-loving plants

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Alocasia Zebrina planted in Leca

Perlite, Leca, and sand are ingredients for your soil to improve drainage. This might sound strange as an ingredient for soil that you'd want to improve the water retention of, but there is a good reason.

When you add Vermiculite, Sphagnum moss, and/or Coconut coir, you add material to your soil that hold on to a lot of water. This soil will want to compact to retain as much moisture as possible. This is bad for drainage, because the excess moisture will stay behind in the soil. This is why you need to break up the soil into draining and retaining pockets. You can do this by adding Leca, Perlite, or Sand to your soil mixture.

The Leca, Perlite, and sand make sure that any excess water is quickly draining to the bottom of the pot. Leca and Perlite also help to keep the shape of your soil to prevent the soil from compacting. It can do this, because Leca and Perlite are quite large, unlike sand. By breaking up your soil, you prevent overwatering and allow the flow of oxygen to the plant's roots.

You can use Perlite, Leca, or Sand, either works well and you can pick the one you prefer.

If you'd like to learn more about improving drainage of your soil, including other ways not mentioned here, have a look at "How to make your soil drain water quickly?".

Conclusion

When you give your moisture-loving plants the moisture they want, they'll be happy plants for a long time. There are a few ways to keep your plants happy with long-term solutions. These long-term solutions help you feel at ease, but also help your plants thrive.

You can improve the water retention properties of your soil by adding vermiculite, sphagnum (peat) moss, and/or coconut coir. When you make the soil retain more moisture, you'll also need to improve the drainage to prevent any watering issues. You can improve the drainage by adding perlite, Leca, and sand to your soil. A combination of these ingredients will make sure your plants are always in the soil they love: a lot of moisture, but not wet; plenty of oxygen to prevent pests, and plenty of nutrients to grow with.

Thank you for reading this post! I hope it helps you to keep your plants healthy and beautiful! If you're looking for more guides on specific plants, you can always request a plant guide or donate a plant in order to get a guide for the plant you have trouble with.

Tags: leca, perlite, vermiculite, soil

Posted on: May 2, 2021

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