Why do cremation ashes need treatment before planting?

The science behind healthy memorial plants

It starts with soil.

Healthy memorial plants start with healthy soil. And cremation ashes, on their own, aren't compatible with plant life — no matter how much we might wish they were.

If you're holding ashes and wondering about planting (whether it's a tree in the backyard, a garden at the cottage, or scattering somewhere meaningful), this page will help you understand what's actually happening at the soil level, and what you can do about it.

  • At first glance, you might think cremation ashes are beneficial for plants. After all, they contain nutrients that gardens need — nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sulphur (S).

    But ashes also have components to their chemistry that make them harmful to plants and the environment (see a more detailed explanation on the science below).

    The good news: after years of research, we can now solve this problem. Our Planting Kits balance 22 of these factors, including pH and sodium, so ashes can return to earth and support new life.

  • There are multiple factors that make cremation ashes incompatible with nature. We monitor 22 in total. The top three are: pH, sodium, and sterility.

    Extremely high pH: Ashes have a pH level of 11.8 — similar to bleach — far too alkaline for most plants to tolerate (Ng, 2022).

    Toxic sodium levels: Sodium content in ashes is 200-2000 times higher than plants can handle (Ng, 2022). Even sodium-tolerant species (Pardo & Quintero, 2002) that might initially survive will struggle or fail over time.

    Complete sterility: Ashes are safe to touch, but they're biologically inert (Ng, 2022). They don't break down naturally, even after thousands of years. This means they can't integrate into soil ecosystems the way organic matter does.

    The impact: Research shows that over 50% of plants won't survive direct contact with untreated cremation ashes (Ng, 2022). Seedlings, saplings, and sensitive species are especially vulnerable. When watered, ashes can form a cement-like clump that leaches toxins into surrounding soil — and that clump doesn't biodegrade over time, even in a biodegradable urn (Ng, 2022).

    You don't have to risk a second loss. Our Planting Kits use patented soil science to prevent and reverse these harmful effects, so memorial plants can thrive.

  • Unfortunately, no. The biochemistry of cremation ashes is simply too extreme to be balanced by mixing with regular soil or compost (Ng, 2022). Dilution doesn't neutralize pH or sodium levels — it just spreads the problem across a larger area.

    True compatibility requires a scientifically formulated treatment that addresses the root chemical imbalances. Which is exactly why we developed our memorial planting kits.

  • Our kits are built on over 15 years of research and development that began with our partners Let Your Love Grow®.

    Together with their experienced team, we re-engineered a unique Canadian blend that is made in Canada from 100% Canadian-sourced raw materials. We conduct regular laboratory tests with a certified agrologist to ensure effective results for families and our cemetery clients. Our formula changes slightly year over year in response to environmental conditions and the chemistry of our raw materials.

    The formula balances all 22 key factors — pH, sodium, nutrient availability, microbial activity, and more — transforming cremation ashes into healthy, life-giving soil that plants and ecosystems can actually use.

    The result: Memorial plants that thrive. Gardens that grow. And ashes that truly return to the earth.

    Your funeral home prepares the kit for you — combining the ashes with our soil formula so it's ready to plant when you pick it up. No guesswork, no extra steps. Just a living memorial that's set up for success.

  • While some hardy plants may survive by growing around or away from the ashes, many will not. Seedlings, saplings, and sodium-sensitive species are especially vulnerable. And watering can worsen symptoms as ashes turn to a cement and leach toxins into the surrounding earth. This clump does not biodegrade naturally over time (like many of us imagine). It remains solid in the ground, even with a biodegradable urn.

    Our Planting Kits prevent and reverse these harmful effects, so memorial places can stay healthy and grow.

Here’s the dirt.

If a positive footprint is important to you, let's make a plan. Your funeral home can help — for planning ahead, or even ashes you’ve had for years.

You can also reach out to us directly and we'll help you get started.

Ashes can be fatal to plants and organisms if not properly treated.

Ready to create a living memorial?

Our Ashes to Earth™ Planting Kits are available at funeral homes across Canada. Use them with gardens, potted plants, or scattering in nature. We also work with cemeteries to create full scattering gardens using Ashes to Earth™, where they are cared for in perpetuity.

Currently our partnerships are primarily in Ontario and BC. However, funeral homes in nearly every province have worked with us to support families when requested.

Find a funeral home near you or contact us and we'll connect you with someone who can help — wherever you are in Canada. Your inquiries help us continue to grow our partnerships Canada-wide.

Not sure yet? That's completely okay. Grief doesn't have a timeline. When you're ready, we're here.

Interested in the science?

Our network’s research has spanned the United States, United Kingdom, Australia, and New Zealand—and of course our own work in Canada. Over 15 years, this work has involved scientists including forensic entomologists, anthropologists, pharmacists, landscape architects, and funeral directors. We work closely with a certified Canadian agrologist to ensure every product and shipment of Ashes to Earth™ meets the highest possible quality control.

Citations:

For further background, you can also read more from our partners at Let Your Love Grow™ and Return to Nature.