How Often To Change Soil In Indoor Plants? 3 Mistakes To Avoid

When was the last time you changed the soil of your indoor plants? How often do indoor plants really need to have their soil changed and does it matter when you do it?

If you’re asking yourself these questions then you’re probably thinking it is time to give your indoor plants some brand new soil. So let’s see, how often to change soil in indoor plants?

Usually, you need to change the soil of you indoor plants every 12 to 18 months. Exceptions make repotting, when you move the plant into a bigger pot because it no longer fits into its current pot, or when the soil becomes very hardened. You should not change soil in houseplants more often than than once a year.

Outgrowing its pot and hard soil are the most common reasons why you should replace potted soil in a houseplant.

You can also try to add fresh soil to your indoor plant if you notice that the plant hasn’t been growing in a while, wilts a day or two after watering, or has some discoloured leaves.

Okay, all the above might sound easy-peasy, but in reality, it’s not that simple – changing the soil very much depends on the type of plant, on how much the plant grows, and what is the condition of the old soil, so let’s explore this further.

In my experience, when people consider to change the soil in indoor plants, there are 3 mistakes they are bound to make.

3 Mistakes to avoid when changing the soil in indoor plants

  1. Changing the soil too early. I see this all the time, plants like people love their house. 
  2. Changing the soil during the wrong season. You need to do your research and take advantage of the conditions the weather offers to help your plant thrive.
  3. Changing the soil instead of repotting. Eliminating the plant’s soil when it still has many nutrients and the plant is comfortable with it is a major mistake.

The problem with potting soil is that over time (usually years, but could be months if it’s not high-quality), it becomes squeezed together, closing up the spaces that are typically filled with water and air, so the plant fails to get proper nutrition. If this happens, the sign is that the soil gets hard, so you can easily spot it and replace it with the fresh stuff.

Also, sometimes we can notice some white, fuzzy granules gathering on the potting soil. That’s probably mold. Check this article out to find more about houseplants and mold.

But what do you know? Each type of plant is different, so let’s break it down.

Fast-growing plants need their soil changed every year, as well as a new bigger pot if you want them to grow bigger. Take Devil’s Ivy as a good example for this case. She grows in the blink of an eye so it’s possible that she soon becomes too large for her pot, so repotting her with fresh soil helps her thrive even more.

Slower-growing plants, like Cacti, on the other hand, only need fresh soil once every two years or so. This is because they usually attach to their pot and feel comfortable in it for a very long time. Also, soil replacement can put the plant under a lot of stress, so you don’t want that unless it is necessary, that is, when it needs repotting for instance.

These are general rules of thumb when it comes to soil changing for indoor plants, but you will usually know when it’s time to give your houseplant a fresh boost by replacing the old soil with new one, so you can follow your guts on this.

Changing the soil or repotting?

Changing the soil means replacing the old soil with a new one, full of fresh nutrients, while repotting is when you move the plant from its container to a new one and it does not necessarily include soil changing.

It really depends on what the plant needs. If you’re in doubt which one of these you need to do for your indoor plants, don’t worry, that’s normal. Hopefully, this will help you decide.

3 General rules for repotting

  1. You should generally repot your houseplant if it has become pot-bound, that is if the root system has taken the shape of the pot.

  2. You should also consider repotting if the plant has outgrown its pot and you want to give it more room to grow. If you want to keep the same size, just change the soil or refer to my simple guide on how to keep plants small.

  3. If the plant hasn’t shown any new growth in a while (about one season), it is healthy otherwise and has good growing conditions, you should try repotting your houseplant and adding a batch of fresh soil.

So, unless anything from above happens, you should just change the soil of your houseplant or, if you have enough room, just add a batch of fresh soil.

But when it comes to changing the soil in your indoor plant things are different.

3 General rules for changing the soil

  1. If the soil is hardened you need to change the soil of your houseplant. Feel the soil with your fingers, if it feels compact and has a rather dense texture, it is probably time your plant needs a boost of freshness with new soil.

  2. If you haven’t changed the soil in your indoor plant for more than 3 or 4 years, you should consider changing it, even if the soil looks and feels normal.

  3. If your houseplant has dull foliage and looks like it would benefit from an overall boost of freshness, you should add a batch of fresh soil to its pot.

There is an obvious distinction between changing the soil of a houseplant and repotting it, and you should consider each option separately, but this doesn’t mean they can’t be combined into creating a perfectly-suited environment for your indoor plant to thrive.

Oh and if you decide that you do need to change the soil, don’t throw it away, recycle! Here’s how to do it.

When is the best time to change soil in indoor plants?

The best time to change the soil in indoor plants is usually in spring or summer.

That is the perfect time to repot them too, because that’s when they actively grow and can benefit from a larger pot as well as a nourishment boost from fresh soil.

But that’s not applicable to all plants. Cacti, for instance, makes an exception to this rule.

Cacti active growth happens during the dry season so the best time to change cacti’s soil is in January or February. If you want to know more about caring for cacti in the dry seasonI recommend this quick guide.

Your indoor plants will especially be happy with fresh soil when they need it.

So generally, if you notice that for some reason your plant needs a boost, adding a fresh nutritious patch of soil to the pot is advisable.

Effects of changing the soil on indoor plants

Changing the soil or repotting can be quite stressful for an indoor plant.

A responsible plant lover should know that for houseplants to thrive, they should ideally be left within their nursery comfort. But this is not always in the benefit of your houseplant.

As we now know, there are a few good reasons why you would want to give your plant a fresh batch of soil, so let’s see what are the effects of changing the soil in indoor plants:

The plant will begin to grow.

If your houseplant hasn’t shown any new growth for a long time and you change its soil then you might notice a rapid improvement in its growth and health overall.

Sometimes it just lacks a good deal of new soil, fresh and full of nutrients – just what your indoor plant needs to grow and thrive!

New leaves and flowers will appear.

If you change the soil of your indoor plant, you can expect to see new tiny leaves showing and baby blooms coming out soon.

If this happens, it is quite clear that new soil was what your plant was rooting for (pun intended) in the first place.

It can stay the same and that’s okay.

Staying the same is not unusual in indoor plants who had their soil changed recently.

Event if you change the soil and expect wonders will happen, they might not do for a series of reasons. Maybe your plant is not that picky when it comes to soil.

Aloe, for instance, or Devil’s Ivy are two of the most hard to kill plants. Even if you don’t give them fresh soil, chances are they will still live and grow just fine as long as they get enough light and water. So, if new soil is added, not much difference is noticed.

It can look like it is dying.

This is very rare, but your houseplant can wilt and drop many of its leaves, or even begin to die back a little as a result of changing its soil.

If this happens, it means that the change came quite as a shock for the plant, who was feeling very happy with its old soil. In this case, you need to have patience and give your plant time to adjust.

Don’t worry, as long as your houseplant will continue to have adequate amounts of light and water, it will usually recover soon.

I am sure that by now you know your stuff when it comes to changing the soil in indoor plants, but there are a few more important things you should remember:

Don’t use garden soil for indoor plants, it is not the same as potting soil, it is too dense and can lead to plant disease and pest problems. Potting soil is made up of a mix of composted soil or peat mixture and is enriched with fertilizers to supply the right nutrients for the plant.

You can reuse potting soil if the soil is still light and fluffy. Houseplants can get attached and feel really cosy with their pot and growing environment, so if you must change the soil for some reason but you notice that the old one is still usable, don’t waste it!

Use it again, but first, I recommend you do these things:

  1. Turn the old soil, move it around and take a very good look at it. The soil should still be fluffy, not too dense and compact and it should not have bugs in it. If any of these two happened, dispose of the soil.

  2. Remove extra organic matter. Get rid of any old wigs and leaves, even roots if they don’t look healthy. If roots are creamy-white and sturdy, the plant is healthy. If some roots are yellowish or even brown, cut them to allow the plant to grow new healthy roots.

  3. Add nutrients to the old soil. The used soil has already served the plant with nutrients and over time, its nutritious quality ebbed away. This is why you should enrich the old soil with some plant food before you put it back in the pot.

Okay, you’re done! Now that you’re a changing soil expert, I challenge you to go and assess your plants.

Put your newly gained knowledge into practice and see if your indoor plants need their soil changed.

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