You can buy products to neutralize cremation ashes but it can take four months before the soil is safe for use with young plants. Avoid the need to neutralize the ashes by spreading thinly near more established trees and shrubs or purchase a biodegradable urn which keeps the potentially harmful ashes away from young plant life until they are more established.
Many people choose to scatter or bury the ashes of their loved one in gardens, parks, woodland and so on. Although ashes are natural it doesn’t necessarily mean that they’re good for vegetation. Neutralizing the ashes can reduce negative impact on the environment.
Do I need to neutralize cremation ashes?
If you are scattering the ashes around established trees or shrubs you shouldn’t need to neutralize or treat the ashes. Around plants it might still be best to keep the amounts small. Scattering over a larger area rather than all in one spot would be better as this is going to have less impact on the pH of the soil and avoid releasing concentrated amounts of salt.
If you intend to use the ashes (mixed with soil of course!) to grow a tree, shrub or plant as a memorial to your loved one then adding concentrated amounts of cremated remains could harm growth or even worse. This is especially true when growing in a container or planting seeds, seedlings and saplings. The roots of seedlings are more likely to be affected than the roots of established plants.
How To Neutralize Cremation Ashes
Mixing the ashes with lots of soil will help, but it might not be enough to deal with the sodium or high alkalinity levels. That said, obviously the ratios matter here, so in theory you could use such a large amount of compost or soil that it might mitigate the issues with the ashes. But that probably wouldn’t be convenient especially if we plan on scattering the ashes in a small area.
There are products available that will help convert cremated remains into organic matter that will be actively beneficial to plant life. They address both the high pH and salt levels we would like to reduce. Even with these products we could be faced with a long wait before the product takes effect, up to four months. During this time bacteria which forms part of the soil treatment product interacts with the ashes and converts them to a more plant-friendly medium ready for scattering or growing.
Natural methods to increase the acidity of soil
There are soil amendment products available that will alter the pH of soil. For example, powdered elemental sulphur can be mixed with your soil to increase the acidy levels. But it can require multiple treatments and take months to see results.
We would also have to wait before planting seeds/seedlings in it. Again not convenient and it doesn’t address the high salt content we need to deal with either.
Reducing salt levels in soil
Reducing salt levels in the soil can be done by adding activated charcoal and compost. The area should be watered regularly in order to move the salt deeper in to the soil. What we’re aiming for is to get the salt to gradually descend below where the roots are going to be. This also is going to take time and effort.
Is there a quicker way to neutralize cremation ashes?
Well, yes and no! The options discussed above presume that we want the ashes to be more environmentally friendly before we use them in our garden so that it doesn’t harm young seedlings. But that’s not always necessary.
If we are scattering the ashes and want to scatter them in a small area near young plants it’s difficult to see a quick way of reducing any negative impact. It’s a case of being patient or taking the risk.
But if we are burying the ashes, there may be a swifter solution. Burying the ashes in a biodegradable urn will keep the ashes away from young roots of anything planted above. By the time the urn breaks down the tree (for example) will be established and able to cope with the minerals being released by the ashes.
To be extra safe you could bury the urn at a greater depth so that a smaller proportion of the roots come in to contact with the ashes.
Often ashes will not fill an urn completely so adding soil or compost will prevent there being an air pocket once the urn breaks down, it will also provide a ‘boost’ to the tree growing above!
An all-in-one solution
If you’re looking to grow a memorial tree there is a clever idea pioneered in 1997 by Bios Urn and launched for sale in 2012. They came up with an all-in-one solution to grow a tree from cremated remains. In the years between it’s creation and launch research involving various soil experts was conducted.
The result is a biodegradable urn which has two sections, in one you place your loved ones ashes and in the other is the soil and chosen seed or seedling. This way the ashes are kept separate from the establishing seedling avoiding damage to the young roots – in the same way as mentioned above.
It has had years of testing both pre and post launch which suggests it’s effective. There are now other companies offering similar products. Click here for current Amazon prices.
We really like the ethos behind this idea, not just the environmental aspect but also the symbolism of the ashes being transformed in to new life. Some people even buy them in advance for themselves and let their family know that they want to be a tree!
Even though they’re not exactly cheap they do become a focus for loved ones for years to come.
I didn’t realize that cremation ashes could be harmful to seedlings. Like many people I though they would be inert, neither particularly good but at the same time not bad either. I know salt isn’t good for plant life but didn’t realize that ashes had high sodium levels.
Avoid scattering ashes near plants. Established trees and shrubs should be okay, but spread thinly to be safe. If for some reason you insist on scattering near young plants then use a soil amendment – this means waiting. If you want to scatter near young plants without treating the ashes then you may be risking harm to those plants.
Burying ashes in a biodegradable urn at sufficient depth gives seedlings time to establish thus reducing the chance of harm from salts and high alkalinity levels. Seeds, seedlings and saplings should be planted in a way and in a location that’s best for that particular plant to give it the best possible start.
People also read: 10 Ways To Scatter Ashes