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How Long Will Cremation Ashes Last at Home? In a Niche? If You Bury Them?

How Long Will Cremation Ashes Last at Home? In a Niche? If You Bury Them?

For those that choose to keep ashes of a loved one at home, a concern that sometimes comes up is: How long will cremated remains last? The answer to this changes based on what is done with them and where they are kept. This article looks at keeping them at home as well as depositing them in other places. 

What are cremated remains or ashes? 

Before looking at external factors affecting how long cremation ashes will last, it is important to look at the composition of ashes.

Cremated ashes are created when the body of person who has died is exposed to extreme heat (flame cremation) or water, heat and pressure (aquamation) so that organic matter is reduced to bone fragments. These remains are then reduced further into fine particles that look like sand or coarse dirt; this is referred to as “ashes” or “cremated remains.”

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The chemical composition of cremated remains is mostly calcium phosphate (from the human skeleton) but can also contain small amounts of minerals like potassium and sodium. Additionally, the pH of ashes is high and contains high amounts of salt. Moreover, ashes do not biodegrade naturally. Instead, they mix with soil, water, or air around them if they are buried or scattered. 

How long do ashes last in the ground 

How long ashes will last when buried in the ground is influenced by how they are buried. For example, if ashes are buried without an urn, it will not take long to incorporate them into the soil and surrounding organic material. The same could be said for scattering ashes on land. In contrast, burying ashes in an urn can take several years to decades to breakdown, depending on the urn material. However some biodegradable urns are designed to decompose quickly. Some urns turn into trees.

Many urns contain chemicals and have treatments applied to last longer. Those urns would not be an ideal urn choice for ash burial. Although this option may last longer in the ground, it can be harmful to the environment.

Instead, it is advised to use urns made from biodegradable materials such as paper, clay, plant, bark, wood, sand, and other materials that naturally decompose over time. You can opt to further aid in incorporating the ashes and organic matter by choosing an urn with a blend of soil that is better for plants or by selecting an urn that mixes ashes with a seed or seedling.

Although a small amount of ashes buried in an area is unlikely to have a largely negative environmental impact, it is still advised not to bury ashes in small gardens, flower beds, or under trees.  

How long do ashes last in water

Another popular location when burying or scattering is in bodies of water. Like burials, how long ashes last will depend on the medium in which they are incorporated into the water. However, cremated remains will often distribute and disperse quickly regardless.

Scattering ashes on water directly would be the quickest way to do this. However, it is also possible to purchase biodegradable urns made from materials that degrade more effectively in water, such as paper and cardboard.   

Overall, ashes do not dissolve or disappear in water. Instead, they disperse evenly within the water, which will likely have no harmful effects if the body of water is large enough, such as the case with oceans and lakes. A way to help reduce environmental impact further could be by incorporating ashes into an artificial coral reef, offered by Eternal Reef.  

How long do ashes in an urn kept at home 

Keeping cremated remains in an urn at home will likely result in ashes lasting the longest. However, this depends on factors such as urn material and location. For example, urns made to remain at home are often treated with chemicals to make them last longer; therefore, most will likely last for years, and even an adult's lifetime. However, materials such as metal or ceramic will probably last longer than wood. Nonetheless, certain materials may be more susceptible to breaking (e.g., glass).

The same holds true for location. For example, ashes in urns kept in a home in a safe place away from temperature extremes, water or protected from breakage.

How long do ashes in an urn last if they are kept in a columbarium?

In contrast, keeping an urn in a columbarium at a cemetery especially one that is closed off, shields the urns and the ashes from the elements, making them last for decades or more. 

Nonetheless, many factors can help or hinder the protection of the urn, but the ashes inside are likely to last longer with a strong seal on the urn. This minimizes the incorporation of the ashes into the air and environment around them.   

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