Do post wildfire conditions impact plant growth?

Hi, my name is Aaron, and I am in Grade 8. From this project, I learned that balance is very important in nature. Even though wildfires can seem harmful, they can also help the ecosystem by returning nutrients to the soil.

This matters to my community because we experienced wildfires last summer, and the land needs time to heal. My family and community depend a lot on nature for survival, so it’s important for us to understand how wildfires impact the land and how we can care for it. My results show that small amounts of ash can help some plants grow back, which supports wildlife and keeps the environment healthy. Learning about this can help us better protect and manage our land after wildfires.

My hometown has faced many challenges, including problems with housing, clean water, and access to medical care. Wildfires have made things even harder by damaging the land and forcing people to leave their homes and live with uncertainty. Even with these struggles, our community remains strong and hopeful for a better future.

This video shows my hometown:

Seriously Re-wired. (2025, October 20). Leaf Rapids Manitoba "Copper Dreams"

YouTube. HTTPs://www.youtube.com/watch?v=Bx_ZZdaAMbM

I chose my science project on the effects of post-wildfire conditions on plant growth because the wildfire that occurred in my community and had a strong, visible impact on the land and the people who live here. In a small northern Manitoba community like mine, we rely closely on the land for travel, hunting, and gathering plants, so changes caused by a wildfire are noticeable and affect daily life. After the fire, I saw large, burned areas and noticed how different the soil looked compared to unaffected areas. This sparked my curiosity about how the fire changed the soil and whether those changes would help or harm the growth of plants.

I wanted to investigate how wildfires affect soil nutrients and plants because the land needs to recover naturally, and regrowth of plants is essential for wildlife, the environment, and my community. I was particularly interested in whether the ash left behind could act as a fertilizer or if too much ash would make the soil unhealthy for plants. By comparing plant growth in burned soil with various amounts of ash to growth in regular soil, I could see how different levels of post-fire ash influence plant development.

This project was meaningful to me because it combined my interest in science with an event that had real consequences for my home and neighbors. I had the chance to learn about how ecosystems recover from wildfires and how people can better understand and care for the land after a fire.

I conducted this experiment to study how plants grow in soil mixed with wildfire ashes. First, I collected ashes from my community and prepared different mixtures by combining soil and ashes in various percentages. I used a scale to measure equal amounts and placed each mixture into separate containers.

In my first trial, I planted lettuce seeds, but the plants became too weak, so I restarted the experiment using radish seeds, which grow faster. In each container, I planted seeds and watered them with 100 mL of water regularly.

My independent variable was the amount of ashes mixed with soil. I tested different ratios: 10%, 20%, 30%, 40%, 50%, and 100% ashes. My dependent variable was the growth of the plants, which I measured by counting how many seeds sprouted and measuring their height over time.

The control group was a container with 100% soil and no ashes, which I used to compare how plants normally grow. My controlled variables included the type of seeds (radish), the amount of water (100 mL), the number of seeds in each container, the size of the containers, and the amount of light they received.

I also tested the pH level of each container by overwatering the soil and collecting the drained water. I used pH strips to measure the acidity of each mixture.

Throughout the experiment, I recorded observations such as plant height, color, and strength. At the end, I removed the plants to measure their roots and organized my results into graphs for my science fair display. By following this process, I was able to compare how plants grew in different soil conditions and better understand how wildfire ash affects plant growth.

The results of my experiment showed that wildfire ash affects plant growth in different ways depending on how much ash is mixed into the soil.

The main finding was that plants grew best in soil that contained a moderate amount of ash especially the 40% ash mixture. These plants had the greatest average height compared to all other groups. This suggests that a small to medium amount of ash can improve plant growth by adding nutrients to the soil.

In contrast, plants grown in 100% soil did not grow as tall as those in the 40% ash mixture, but they developed the longest roots. This shows that regular soil is still better for strong root development.

Plants grown in 100% ash had some unexpected results. They germinated the fastest and had redder stems, which shows that ash changes how plants grow. However, these plants did not grow as tall as those in mixed soil. Interestingly, their roots were longer than most of the mixed ash groups. This may mean the plants were trying to grow deeper roots to search for nutrients or water in poor soil conditions.

Another important result was that plant growth did not steadily increase with more ash. Instead, growth improved up to a certain point (around 40%) and then began to decrease as the ash content increased. This supports the idea that too much ash can harm plant growth, likely because it changes the soil’s pH and makes it too alkaline.

To analyze my data, I calculated averages for plant height and root length. I used averages because they help show overall trends and make it easier to compare different groups without showing all raw data. I also compared the number of seeds that germinated in each pot to understand how ash affected sprouting.

Overall, my results support my hypothesis. Small amounts of ash helped plants grow better than regular soil, but large amounts of ash reduced plant growth. This shows that after a wildfire, some ash can help the environment recover, but too much can slow down plant regrowth.

The results of my experiment show that wildfire ash can both help and harm plant growth, depending on how much is present in the soil. I found that plants grew best in soil with a moderate amount of ash, especially around 40%. This suggests that small amounts of ash can improve soil by adding nutrients that help plants grow taller and stronger.

However, when too much ash was present, plant growth decreased. This supports the idea that high amounts of ash can make the soil too alkaline and limit plant growth. Even though plants in 100% ash germinated faster and developed longer roots than some groups, they did not grow as tall, which shows that ash alone is not a good growing environment.

From this experiment, I learned that balance in soil composition is very important for healthy plant growth. Wildfires are not only destructive, but they can also play a role in helping ecosystems recover by returning nutrients to the soil. However, too much ash can slow this recovery.

These findings are important for understanding how land in my community recovers after wildfires. They show that some ash can help new plants grow, which supports wildlife and the environment, but too much ash may delay regrowth. This information could help people better understand how to support natural recovery after fires.

I would run the experiment for a longer period to observe full plant growth. I would also test different types of plants to compare how each reacts under the same conditions. Another improvement would be layering ashes in different amounts or depths to see how this affects plant growth. I would also do a water test and a drainage test. I would collect samples from the same location next year to track changes over time. This step is important to me because my community experienced a forest fire last year, and my family relies on the land.

I would like to express my sincere gratitude to Grow North for providing the space and

opportunity to work on my science project. I would also like to acknowledge Ms. Martin

for her dedication to science. Additionally, I extend my appreciation to the school for organizing the science fair, which provided me with the opportunity to further develop my knowledge and

understanding.

Western Fire Chiefs Association. (2023, January 25). 10 wildfire facts for kids. WFCA.

https://wfca.com/wildfire-articles/wildfire-facts-for-kid/

Odsen, S. (2018). A wildfire story: Soil. fRI Research.

https://friresearch.ca/news/a-wildfire-story-soil

Images:

NASA FIRMS. (n.d.). Fire Information for Resource Management System (FIRMS) map. NASA Earth Science Data and Information System (ESDIS).

CTV News. (2025, July 24). Wildfire enters Leaf Rapids [Video].

https://www.ctvnews.ca/winnipeg/video/2025/07/24/wildfire-enters-leaf-rapids/

Jarvie, N. (2025, August 31). Photos of wildfire in Leaf Rapids [Photographs].

Facebook.

https://www.facebook.com/...

Seriously Re-wired. (2025, October 20). Leaf Rapids Manitoba “Copper dreams” [Video]. YouTube.

https://www.youtube.com/watch?v=Bx_ZZdaAMbM

This video highlights the community of Leaf Rapids, Manitoba, showing its history and challenges. It connects to the topic by illustrating how wildfires and other issues have affected the town and its residents. It helped provide a personal and local perspective on the impact of environmental and social challenges.