Upcycle Paper Products into Plantable Seed Paper

Abstract

Do you ever have notebooks and papers left over from the school year? Do you recycle them? What if you could use them to start your garden instead? In this science project, you will upcycle old paper into seed cards and test how paper compares to other materials as a fertilizer! 

Summary

Areas of Science

Plant Biology
Agricultural Technology

Difficulty

Method

Scientific Method

Time Required

Long (2-4 weeks)

Prerequisites

None required.

Material Availability

All materials are readily available.

Cost

Low ($20 - $50)

Safety

Adult supervision is required when using a blender. 

Credits

Laura Ohl, PhD, Science Buddies Alumni

Science Buddies is committed to creating content authored by scientists and educators. Learn more about our process and how we use AI.

https://www.youtube.com/watch?v=iIdDMVw4PFU

Objective

In this science project, you will upcycle paper products to make seed paper and test its impact as a fertilizer on plant growth.

Introduction

In 2022, the US was able to recycle about 68% of the paper consumed, according to the American Forest & Paper Association. What has driven the high percentage of US citizens to recycle paper and cardboard, but not necessarily other materials such as plastics? One contributing factor is that 94% of Americans have proper access to a local paper recycling program. The accessibility and education on paper recycling over the last few decades have led to significant paper waste reduction. It has even led to consumer trends in preferring paper products over plastic products when shipping items. Many consumers demand to buy materials that reuse waste materials, including items made from recycled paper. So, how is paper made, and why is paper recycling so important?

In the US, most paper comes from trees. These trees are cut down and processed to create a cellulose pulp that can be pressed into paper through costly chemical or mechanical methods. What if, instead of using these complex processes from new materials, we could reduce the amount of waste produced and reuse the paper already produced to decrease the amount of chemicals needed for paper production? Although paper recycling is widely adopted in the US due to its accessibility, responsible recycling is also an important factor in ensuring that all items attempting to be recycled actually are recycled. Wishcycling, or recycling an object you wish could be recycled but cannot be in your area, negatively impacts the sorting recycling process and can disqualify other recyclable items from being recycled. Therefore, it's important to know your local recycling guidelines on what can and can't be recycled in your area. Responsible recycling, paired with waste reduction and reuse efforts represented in Figure 1, will also create a more circular economy and a more sustainable future. How can we reduce waste production and reuse already produced materials?

Image Credit: Laura Ohl, PhD / Science Buddies

Inverted pyramid showing the order of operations to live a zero waste life, include refuse, reduce, reuse, recycle, or rot.

Composting is a great way to reuse food scraps and plant-based fibers, which are nitrogen-rich organic materials needed for plant growth. But what if you don’t have the time, resources, or space to compost them? One of the great things about paper is that it’s already partially broken down or biodegraded into plant-based cellulose fibers. These fibers can act as a slow-release fertilizer for your plants to help them grow and even help the structure of the soil. Slow-release fertilizers are more advantageous for plants than quick-release fertilizers since they release nutrients at a slower rate throughout a plant's lifetime. Additionally, they allow for less frequent fertilizer applications, as most commercial fertilizers are soluble quick-release fertilizers that require more applications in the same amount of time. Slow-release fertilizers are not widely adopted by large farms yet because they require resource planning, require more distribution time, and are currently more expensive than quick-release fertilizers. 

Image Credit: Laura Ohl, PhD / Science Buddies

Repletion of soil with fertilizers aids in addition of nitrogen, phosphorous, and potassium back into the soil after being used by plants.

Plants need 16 essential nutrients to grow, including nitrogen (N), phosphorus (P), and potassium (K). These nutrients are important chemical elements found in the soil and are also important parts of fertilizers, as seen in Figure 2. Other non-soil materials do not have as many of these nutrients, such as coconut husks. Many fertilizers you buy at the store list the relative amounts, or ratios, of nitrogen, phosphorus, and potassium (N-P-K) on the label. Different plants need different N-P-K ratios to grow their best. Gardeners improve their soil quality by adding quick-release fertilizer, which encourages plant growth by making nutrients more available to the plants. However, quick-release fertilizers have to be reapplied frequently, which contributes to nutrient runoff into local waterways and can harm the environment. How could that change with the broader adoption of slow-release fertilizers? Many other materials, including cardboard, leaves, and newspaper, are already used as slow-release fertilizers in gardens. These materials provide essential nutrients to the soil and also improve the drainage of the soil. So, how could these slow-release materials be more widely used? 

Seed cards are a great way to increase use and teach others about slow-release fertilizers! Seed cards are upcycled or reused paper products made from paper waste. Seed cards are meant to be enjoyed and then planted. Interestingly, the paper contains trace nitrogen, phosphorous, and potassium nutrients like other fertilizers. Paper as a fertilizer can also help with soil properties, moisture retention, plant growth, and weed control. These cards are also a great alternative to glossy, non-biodegradable greeting cards. Seed cards offer a sustainable solution because they reuse waste products and allow for their reuse as a fertilizer for plants!

Seed cards typically contain non-invasive local seeds, such as wildflowers, to give to local family and friends. If you decide to share some of your cards with others, comply with the USDA guidelines on what seeds are safe to use in your area and send them within the US (more information in the bibliography references). You could even compare your results with those of your friends. When you make these cards, you know that 100% of the paper is being reused from your own post-consumer waste! In this science experiment, you will learn how to upcycle paper products into seed paper and test which materials make the best fertilizer for your plants.

Terms and Concepts

• Recycle
• Paper recycling program
• Waste Reduction
• Cellulose pulp
• Wishcycling
• Local recycling guidelines
• Circular economy
• 5 R's of zero waste 
• Plant-based fibers
• Cellulose fibers
• Fertilizer
• Slow-release fertilizer
• Quick-release fertilizer
• Essential nutrients
• Chemical elements
• Runoff
• Upcycle
• Post-consumer waste

Questions

• Why is paper recycling more widely adopted in the US than plastic recycling?
• What is most paper made from? Has this changed over the years? 
• What other materials can paper be made from besides trees?
• What is the difference between quick-release and slow-release fertilizers?
• How does wishcycling impact recycling? 
• What are some essential nutrients in fertilizers? 
• How do soil and coconut husks differ in their nutrient content? Which has more and which has less? 
• What is upcycling?
• What is post-consumer waste, and who is responsible for it?
• Upcycling used paper products is which of the 5 R principles of zero waste? (It can be more than one!)

Materials and Equipment

• Blender (preferably no longer used for food)
• Fine-mesh strainer or splatter guard
• Bowl or sink
• Paper product options: Used notebook paper, printer paper, construction paper, paper bags, newspaper, or tissues
• Scissors (optional)
• 9-15 Pots (or cups with holes in the bottom for drainage)
• Plant seeds: we recommend basil, marigolds, or zinnias
• Coconut husk or coconut coir
• Commercial fertilizer

This project follows the Scientific Method. Review the steps before you begin.

Make the Seed Paper

To make the seed paper, you will break up the paper product, rehydrate it with water, and then dry it. This will take two days since the paper needs to dry overnight. To thoroughly test your seed paper, make three of each paper type that fits into the pots. Make sure to shape your seed paper before adding your seeds to ensure they will fit in your pots for testing the fertilizing capabilities of each paper product. 

1. Rip up several pieces of paper into small pieces with your hands or scissors.
2. Cover the paper with water and soak the paper for at least 10 minutes.
3. Blend the soaked paper and water in a blender until it turns into a pulp.
   1. CAUTION: Do not use a new blender! Paper can dull and ruin the blades. Instead, use an older blender you plan to use only for experimentation, not food. (Instead of using a blender, you can rip up the paper into very tiny pieces.)
4. Place the strainer over a bowl or sink. Then, transfer the pulp to the strainer by pouring the blended-up pulp onto a strainer over the bowl. This will remove excess water, but do not squeeze the pulp yet!
   1. Note: When making your seed paper, make sure to shape your pulp into a similar size to fit in your pots so they can fit into them when you test them! If you do not do this step, you will have to cut the seed paper to size and re-count the number of visible seeds in the seed paper to compare to your control. 
5. Count out a consistent number of seeds for each piece of seed paper to track how many germinate. 
   1. Note: We recommend growing at least 4 seeds per condition or piece of paper. 
6. Carefully add the seeds, evenly spaced apart, on top of the pulp to incorporate it into the paper. 
   1. Remember: Your pulp shape should be the same dimensions as your pot. If it is not, you will need to cut it and re-count the number of seeds! 
7. Gently press the pulp into a thin layer on the strainer.
   1. Note: This will also help cover the seeds, although covering them is not necessary for the seed paper to work. 
8. Wait for the paper to dry overnight (12-24 hours). You can use a fan to help it dry quicker, but this is optional.
9. The next day, pour off any excess liquid in the bowl below down the drain.
10. Once the paper has dried, lift it from the strainer, and it will be ready to use!
    1. Note: Once the seed paper is dried, it is shelf-stable because the seeds are still dormant in the dry paper. Therefore, you can either continue the experiment right away or at a later date.

Test the Seed Paper as a Fertilizer

You will prepare one pot for each condition. For example, if you have two controls (positive and negative) and three types of seed paper to test (newspaper, notebook paper, and construction paper), you will need five pots total for a single trial. We recommend completing at least three trials, so you would need a total of fifteen pots. You can scale this up or down based on the number of seed paper types made from different paper products that you want to test. Observe the plants daily for four weeks to see how the fertilizers impact plant growth over time.

1. To rehydrate the coconut husk, pour the dry husk into a container and add a similar amount of water to the top. 
2. Mix the husk with the water until it has a soil-like consistency.
3. Add coconut husk to pots until they’re ¾  full or 1 inch from the top.
4. Add either your plant paper or fertilizer and seeds to each pot.
   1. Positive control: Add ¼ teaspoon of liquid commercial fertilizer once a week + seeds (same amount as seed paper).
   2. Experiential conditions: Add each type of seed paper to a separate pot (no seeds, already added to paper).
   3. Negative control: Do not add any fertilizer + seeds (same amount as seed paper).
5. Add a thin layer of coconut husk over each fertilizer or seed paper. Your seed packet will help you determine the best depth for the seeds! 
   1. Note: To ensure consistency of your results, add each type of fertilizer at the same depth as your experimental controls to accurately compare it to your seed paper made from different materials.
6. Place the plants in a sunny place or under a grow light to encourage germination and plant growth.
7. Check the plants daily for new growth, record your measurements, and water consistently for each condition (for example, every 3-4 days or when the soil is dry).
8. Record the following measures of plant growth daily for 4 weeks:
   1. Record the number of seeds that germinated or how many seeds became plants. This is known as the germination rate, or how many seeds germinated divided by the total number of seeds planted. 
   2. Record the time to germination for each seed or how long it took for the first signs of a shoot above dirt.
   3. Calculate the average germination time of all of the seeds in days. Add all of the times together and divide by the total number of seeds planted. 
      1. Note: If one or more of the seeds did not come up, exclude it fom this calculation. 
   4. Measure the height of the plant from the top layer of the coconut husk to the top of the plant. 
   5. Calculate the average height of all of the plants that germinated. Add all of the heights together and divide by the number of plants that germinated.  
      1. Note: If one or more of the seeds did not become a plant, exclude it from this calculation. 
   6. Measure the length of the longest leaf on each plant.
   7. Calculate the average length of the longest leaf for all of the plants that germinated. Add all of the lengths of the longest leaves of each plant together and divide by the number of plants that germinated.  
      1. Note: If one or more of the seeds did not become a plant, exclude it from this calculation.  
   8. Measure the diameter of the largest flower (if a flowering plant). 
9. Create a table for daily measurements, and track the changes daily for about four weeks. 
   1. Note: This experiment can be longer or shorter depending on the seeds you use. You can check the seed packets to see the expected germination time for each plant, although the germination rate can change depending on many variables! The seeds recommended in the materials list usually take about four weeks to grow enough to use the fertilizer, so adjust your experiment if you are using other seeds. 

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Types of Fertilizer	Germination rate (days)	Time to germination for each seed (days)	Average germination time of seeds (days)	Height of each plant (cm)	Average height of plants (cm)	Length of longest leaf per plant (cm)	Average length of the longest leaves (cm)	Diameter of largest flower (cm)
Seeds with no fertilizer (negative control)		Seed 1: Seed 2: Seed 3: Seed 4:		Plant 1: Plant 2: Plant 3: Plant 4:		Leaf 1:  Leaf 2: Leaf 3: Leaf 4:
Seeds with commercial fertilizer (positive control)		...		...		...
Seed Paper 1 (material 1)
Seed Paper 2 (material 2)
Seed Paper 3 (material 3)

Table 1. Data table to track the impact of fertilizers on germination, plant growth, and flowering.

Conclusion

• Which conditions have similar or dissimilar germination rates? Does the type of fertilizer impact germination?
• Does each fertilizer have a similar effect on plant growth (length of shoot, leaves)?
• Is fertilizer alone enough to grow the plants, or are other nutrients provided by soil needed for long-term plant growth? Use your results to inform your answer.
• Review the introduction to recall what chemical components are in each fertilizer. What important components are needed in soil and fertilizers for plants to germinate and grow? Does each fertilizer have enough of these components to grow the plants in this short timeframe? Why or why not?

Ask an Expert

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Global Goals

The United Nations Sustainable Development Goals (UNSDGs) are a blueprint to achieve a better and more sustainable future for all.

This project explores topics key to Responsible Consumption and Production: Ensure sustainable consumption and production patterns.

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