What Is The Difference Between Akadama And Molar Clay?

Akadama is a very well regarded soil component that comes from Japan and everyone pretty much says it is the best thing you can use for your bonsai.

Molar clay is often cited as the cheaper alternative to akadama and often it is said that this is the only difference. However, while they are similar and can both be used as bonsai soil, and there are a number of differences.

Both will give you good results, so really it’s down to you to decide which one you prefer and which of the nuanced differences suit your bonsai needs more.

They Are Materially Different

When we look at akadama and molar clay, they are materially very different. You will see below they have a lot similarities in how they function as a soil, but if you put that to one side, they are in fact totally different.

Akadama is basically a naturally forming volcanic clay that is only found in Japan. Whatever minerals are in the Japanese soil, they have been mixed to form a clay and then with the heat of the volcanoes, the result is the very unique akadama. It is quite soft and absorbent, but it is hard enough to hold its own structure when wet.

Molar clay is made from diatomaceous clay, which means it is fossilised sea creature skeletons. This is then treated with a high heat to make it calcined, or a ‘baked clay’  which basically means it becomes very hard and also absorbent.

The Price Is Different

One of the big differences between the two soils is the price. Akadama is always going to be a lot more expensive, simply due to its availability and the fact that it needs to be imported.

I have generally found that I can buy twice as much molar clay …for half the price of akadama. So you can quickly see that is quite a large difference.

From memory I bought 30L of molar clay for about 15 quid, where as akadama is sold as 14L for about 30ish, maybe 40 quid.

It’s not exactly going to break the bank, but it’s still enough to influence someone’s purchasing decision; it certainly played a heavy role in mine.  

(You can read more about – Is Akadama Worth Buying For Bonsai?)

The Availability Is Different  

Molar clay is much more readily available compared to akadama. Molar clay is usually sold as all sorts of different products since it used in a wide number of industries and you can easily pick it up in the form of cat litter or absorbent granules.

Akadama is harder to come by, as it is usually only sold by bonsai specialists and it is really only mined and sold to be used as a soil for bonsai and other similar plants.

The fact that it is also imported from Japan also means that it is generally harder to source, but luckily internet shopping can help us with this problem.   

Molar Clay Does Not Break Down

Molar clay does have an advantage over akadama in the fact that it will not break down. It may get chipped and damaged, so some of the particles get smaller, or turn to dust, but overall it will stay intact.

Molar clay will also survive the freeze thaw cycle. I am sure it has a limit, but I have found in my mild climate that it is pretty much not going to never break down.

This means that it can be reused. I just have to sift my old soil to separate any dust from the molar clay and then it’s pretty much as good as new.

Akadama will do the opposite and it will break down, usually after 2, maybe 3 years. This will be due to the fact that the roots can grow into the akadama, causing it to split and also due to it freezing and thawing over winter.  

If we bring this back to the price, it makes a difference. Not only am I getting more molar clay, for cheaper …it also lasts pretty much indefinitely, where as the akadama is more expensive and will basically turn to mush after a while. 

(You can read more about – Using Molar Clay As Bonsai Soil (Using Cat Litter))

Akadama Is More Porous

I have just mentioned that akadama will break down and this is because it is more porous …but this isn’t always a bad thing.

Its porous nature is something we actually want. It allows the roots to grow into the soil, which will eventually cause the soil particle to break, but while doing so it will also break the root.

This damage of the roots is actually ideal as it causes the root to regrow and split into two. As it keeps doing this, the roots are only going to become more and more ramified, without you having to do anything.

However, you can still get good roots with molar clay. If you have seen any of my videos you will see I get a lot of success. This is believed to be because the molar clay is hard and sharp, so the roots can’t grow into the molar clay, but they can still get damaged as they scrape past, which causes the same splitting effect.

I am not sure how true this is, but I can say I get good roots with molar clay. Annoyingly I have not used akadama myself, so I cannot compare. I do have a feeling that I will get better roots with the akadama …but the molar clay results are nothing to be ashamed of.     

Both Soils Hold Water

Both akadama and molar clay will hold water, which is why they can make an excellent soil.

Out of the two, molar clay probably holds more water, but whether you see this a negative or positive will really depend on your climate and your soil requirements.

However, it is important that they can do this as it allows you to water your tree and some moisture be held in the pot which will keep things damp.

If you where using something that didn’t hold any water, everything would flush out the bottom and no moisture would be retained. You also do not want the opposite where you add the water and everything stays in the pot.

Both akadama and molar clay allow for a nice balance of water to remain in the pot. Everything will stay damp which is exactly what you want. Then as the pot dries up, the two soils will release their water content back into the pot, helping to keep things moist.

This is really going to allow your pot to keep the perfect level of dampness for a while. 

Both Soils Hold Nutrients

As both soils can hold water, it also means they can hold nutrients too. This means that when you fertilise your tree, some of the elements are absorbed into the soil and then slowly released back out into the pot over time.

This basically helps keep your tree well fed, more of the fertiliser you add will actually get into the tree, rather than being flushed straight out of the pot.

Do Bonsai Growers Prefer Molar Clay Or Akadama?

I’ve gone through the differences, and similarities, but what do people actually prefer? Well, I asked my Youtube subscribers and this was the answer:

As you can see, akadama was more popular than molar clay, although not by much. I think the interesting thing here is that only a very small percent of people (5%) use both and 33% don’t use either, which goes to show there are plenty of other options out there.

Of course this is only a small sample size, but it is still gives us a glimpse of what other bonsai growers are using, and for now, it seems like akadama is more favoured.

Should You Use Molar Clay Or Akadama?

Really there is no right or wrong here. Both can be used and really which one you pick comes down to personal preference and if you want to use something else, that is also fine.

As you can see from what I went through above, they are slightly different and therefore there is a bit of a trade off when deciding what one to use.

Really is down to you to decide what you think will best suit your trees, as well as what is easily accessible and affordable to you.

There is also nothing stopping you buying both and testing them out yourself, so you can see for yourself which one you like better or not.   

(You can read more about – A General Guide To Bonsai Soil)