How Does Using Dried Leaves in Soil Affect Plants?
8-8704
8th Grade
Nativity Catholic School
2024 San Mateo County Office of Education STEM Fair
Abstract
The purpose of this experiment was to test if dried leaves had any affect on plants when adding them to soil. My hypothesis is that using dry leaves would help improve soil fertility and provide plants with rich nutrients such as phosphorus, nitrogen and potassium. Dry leaves are also full of organic matter which benefits the microorganisms already in the soil. They are nature’s own fertilizer so dry leaves would definitely have an affect on plants.
To test my hypothesis I chose three different plants. The Coleus Plant; the Nephthytis Plant and the Snake Plant. All plants were purchased at the same time; their heights were recorded (along with their health conditions); dried leaves were added to their soil and finally each plants care instructions were carefully followed, such as watering, misting and lighting. Because the plants were all different they grew at different lengths. For example, the Coleus Plant almost grew twice its size compared to the Nephthytis plant which only grew one inch in the exact same timing period. In a ten week period, the Coleus Plant grew 6 inches, the Nephthytis Plant, 1 inch and the Snake plant 1 3/4in. In each case, the plants remain healthy and are outgrowing their current pots.
In conclusion, dry leaves do affect plants. The nutrients and organic matter that dry leaves provided to the soil in these plants have allowed them to flourish and sprout rich, healthy looking new leaves as they continue to grow.
Purpose Statement
The purpose of this experiment is to find out if dry leaves affect a plant if they are added to a plants soil. I became interested in this because I would watch my grandparents constantly sweeping a mountain of dried leaves every day for months. I sometimes wondered if all these dead leaves had any purpose once they fell off the trees outside of getting dumped in the recycle bin. I knew that these were naturally discarded leaves and they must have some purpose. I thought about how no one cleans up the rainforest or thick woods and they always seem to be rich and healthy. So, I figured the leaves must have some impact on the soil. I believe this experiment will prove that using dried leaves in the soil will improve the overall health and growth of plants. The fact that leaves are a natural resource and they have nutrients that can benefit our soil, the use of dried leaves should have positive results during this experiment.
The information gained from this experiment can help others understand the value of using dried leaves in their plants and gardens.
Hypothesis
Using dry leaves in soil can improve soil fertility and provide rich nutrients for our plants. Since leaves are coming from a natural source, the nutrients in the leaves would contribute to enriching the plants soil for growth. I believe the discarded leaves from nature would also be a good source of rich organic matter. We know that organic matter benefits microorganisms already in the soil, so it would help break down matter further, which helps the plants.
The use of dry leaves in soil will not only provide benefits to the plants but I believe it would enrich their environment. Overall, dry leaves in soil do have a strong effect on a plants health and growth.
Experimental Procedures and
Materials
Materials Needed
Experimental Procedures and
Materials
Experimental Procedures
Experimental Procedures and
Materials
F) Once you have finely chopped the leaves, place a layer of dry leaves all around the top layer of the plants soil in the pot.
G) Carefully, start poking the dry leaves with your knife into the soil until the chopped leaves are inside the dirt and can’t be seen. (Make sure not to poke to deeply or you will cut into the plants root)
H) Water all around the dirt of the plant until damp. Do not over water.
I) Place your plants according to your plants instructions. Some plants require Bright Light, other filtered lighting, other in shaded light.
Procedures Continued
Experimental Procedures and
Materials
J) Water your plants according to your plant instructions. Some plants require light watering;others may require that you keep them moist only and others to let dry in-between watering.
K) Log any changes you see. Example: Too much watering caused some leaves to fall off or turn brown. Log in at least monthly each plants growth.
L) After two months, add more dry leaves to the plants and follow steps A to K.
Procedures Continued
Experimental Results
To test if using dry leaves in soil can affect plants overall health and growth, start with a batch of dry leaves. Next chop them up using a knife. Your results should be a finely chopped batch of dry leaves. You are now ready to put them in the soil.
The plants chosen for this experiment are, the Coleus plant, the Nephthytis plant and the Snake plant. Each plant’s soil was coated with a layer of chopped dry leaves that were gently pushed into the soil deep enough so that the roots were not disturbed. Added to this experiment was purchasing a Croton plant that was in very very poor condition to see if using dry leaves could help revive the plant. See results of each plant on the following pages.
Dry Leaves Preparation
Experimental Results
The Coleus plant was purchased on September 24th, 2023. It was measured at approximately 7 inches. Chopped dry leaves were added to the plants soil. The plants recommended care was followed which included keeping it moist, by watering it weekly, spraying it with a mist of water as well as being kept in Indirect sunlight. By November 30, the plant had grown to 13 inches.
Results: In a matter of 10 weeks, the plant almost grew twice its height, had sprouted new leaves and remains quite healthy.
Coleus Plant
9-24-23 ( 7in. )
11-30-23 ( 13in. )
Experimental Results
The Nephthytis plant was purchased on September 24, 2023 and was 6 inches. Chopped dry leaves were added to the plants soil. The plants recommended care was followed which included watering until damp, spraying it with a mist of water and providing medium to low light. After 3 days, several of the plants leaves began to brown but this stopped with no further browning occurring. Instead, within 6 weeks the plant had sprouted new leaves spreading width wise. The new leaves are larger and very healthy. By November 30th, the plant had grown only one inch taller.
Results: In a matter of 10 weeks the plant only grew to 7 inches, but grew wider in growth with new stems and leaves. The plant remains healthy.
Nephthytis Plant
9-24-23 ( 6in )
11-30-23 ( 7in )
Experimental Results
The Snake Plant was purchased on September 24th 2023. It was measured at approximately 8 and ½ inches. Chopped leaves were added to the soil. The plants recommended care was followed which included Indirect sunlight, Spraying with a mist of water and letting it dry completely in-between watering. By November 30th, the plant had grown to 10 and ¼ inches.
Results: In a matter of 10 weeks the plant grew and additional one and three quarter inch. No new leaf growth is noted. All leaves are taller and the plant remains healthy.
Snake Plant
9-24-23 ( 8 1/2in. )
11-30-23 ( 10 1/4in. )
Experimental Results
Too see if dry leaves would help revive a plant that was in very poor condition, I purchased a Croton plant that appeared to be dying. The plant was approximately 4 ½ inches. Chopped dry leaves were added to the plants soil. The plants recommended care instructions were followed which included keeping it in bright light, spraying lightly with water and watering every one to two weeks. By November 30, the plant did not grow but completely dried up.
Results: The plant did not survive. It continued to deteriorate regardless of it’s care or adding the dry leaves.
Croton Plant
9-24-23 ( 4 1/2in. )
11-30-23 ( 4 1/2in )
Analysis of Experimental
Results
The objective of this experiment was to determine if dry leaves had any affect on plants when added to their soil. In this experiment the following plants were used: The Coleus plant, the Nephthytis Plant and the Snake Plant. Included in this experiment was the Croton Plant. This plant was in very poor condition. The goal for this plant was to see if it could be revived by using the dry leaves.
The test results varied for each plant. For example, with the Coleus plant it almost grew twice its original size. The Nephthytis Plant only an inch. This plant was the only one that developed a few brown leaves. The Snake plant grew an inch and three quarters. Although each plant grew at different rates, all the plants flourished, appear enriched and remain very healthy.
As for the Croton plant, the addition of the dry leaves along with it’s recommended care instructions, did not help the plant revive. There were only a few leaves that still looked “alive” the rest of the plant was dried up and showed no signs of life.
Analysis of Experimental
Results (continued)
My interpretation of the Croton plant not surviving is that the plant was too far gone and the dry leaves were not enough to bring it back to life. When the plant was purchased the soil was so dried up that it crumbled apart easily. My interpretation of the other three plants is that the dried leaves did have an affect on the plants overall growth and health.
My hypothesis that dry leaves put in soil can improve soil fertility and provide rich nutrients for our plants is shown in the growth and healthy state of the plants in this experiment. Since the dry leaves are coming from a natural source, the leaves contributed in enriching the plants soil and helped the plants overall. As stated in my hypothesis, natures discarded leaves are a good source of rich organic matter and this matter benefits microorganisms already in the soil.
Conclusions
In conclusion, using dry leaves in the soil does help improve soil fertility and provide plants with rich nutrients like phosphorus, nitrogen, and potassium as well as having a source of carbon compounds Dry dead leaves are also full of organic matter which benefits the microorganisms already in the soil. The microorganisms absorb the nutrients and convert them into nutrients that the plants can absorb. The nutrients in the dry dead leaves not only fed the plants but made them stronger as the test results confirmed. My experiment proved my hypothesis that dried leaves coming from a natural source would contribute to enriching the plant’s soil for growth and health. Although each plant grew at different rates, they remained healthy, sprouted new leaves, flourished and continued to grow.
In this experiment, I also included a plant (the Croton) that was in very, very poor condition (dying). I wanted to see if using dry leaves could help revive the plant. Although I followed the plants instructions for its care, the plant did not survive. I can only conclude that the plant was too withered for the dry leaves to have had
Conclusions -Continued
any effect on its survival. Since we know that dry leaves act as mulch and protect the soil from erosion, I had thought that the dry leaves would have saved the plant. Also, knowing that dead leaves make gaps that allow air to pass through the soil into the roots, it would have provided spaces for water and nutrients making me further believe that the dry leaves would have helped it. For this plant though, it was not the case. I would like to know had the dying Croton plant been treated with the dry leaves earlier, would it have had a better chance of surviving? In addition, do dry leaves just not help dying plants survive?
Finally, if I were to continue with this experiment, I would purchase two more sets of identical plants. I would then use dry leaves in one and not the other. I would follow the plants care instructions to see how much of a difference using dry leaves would have made between them.
Acknowledgements
I want to thank my family for all the support and encouragement they gave me throughout this experiment. A special thanks to my grandmother who helped me buy the plants I needed and for setting up a “nursery” for months as I waited for the results.
Bibliography and
Sources
Norman, J. (n.d.). Do Dead Leaves Help Plants Grow? The Effects of Fertilizing with Dead Leaves. Planet and Home. https://planetandhome.com/do-dead-leaves-help
Robuck, A. (2022, December 20). Are Dead Leaves Good For Soil? (Things You Need To Know). Help Me Compost. https://helpmecompost.com/soil/are-dead-leaves-good-for-soil
Lea, J. (2021, April 9). Mixing Dead Leaves into Potted Plants: The Pros and Cons. flourishingplants.com. https://flourishingplants.com/mixing-dead-leaves-into-potted-plants
Mitra, U. (2021, January 25). How to use dry leaves for any plants/Dry leaves natural fertilizer/Easy and free fertilizer. Youtube. https://youtu.be/ZLiPLQOEE/feature
Chapman, M. (2023,June 26). Are Dead Leaves Good For Soil/-Composting Mastery. Compostingmastery.com. https://compostmastery.com/are-dead-leaves-good-for-soil