Do Newspaper Mulch and Cardboard Mulch Differ in Reducing Soil Water Loss? An Experiment

{
“title”: “Do Newspaper Mulch and Cardboard Mulch Differ in Reducing Soil Water Loss? An Experiment”,
**”slug”: “newspaper-vs-cardboard-mulch-experiment”,
“excerpt”: “This beginner‑level experiment lets kids compare newspaper and cardboard mulches to see which one keeps soil wetter longer. By measuring soil moisture over several days, families can discover how simple garden scraps influence water loss.”,
“seo_title”: “Newspaper vs Cardboard Mulch Experiment for Kids”,
“meta_description”: “A step‑by‑step beginner experiment for ages 6‑14 that tests whether newspaper or cardboard mulch reduces soil water loss more effectively.”,
“content”: “

Orientation

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Mulch is a layer of material placed on the soil surface to protect the ground, suppress weeds, and reduce evaporation. Gardeners often use newspaper or cardboard because they are cheap, recycle waste, and break down into organic matter. But do these two paper‑based mulches perform the same? In this hands‑on experiment you will find out which mulch keeps soil moisture higher, using only everyday household items.

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Before You Begin

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• Age range: 6–14 years (adult supervision required for handling tools and the moisture meter).

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• Time commitment: About 30 minutes to set up, then 5–7 days of observation.

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• Location: Choose a sunny spot outdoors or a sunny windowsill where temperature is relatively stable.

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• Safety: Wear gloves when handling cardboard and newspaper to avoid cuts; keep the moisture meter away from water puddles.

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Materials

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• Four identical planting containers (plastic pots, 12‑cm diameter work well).

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• Potting soil (same brand for all pots).

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• Watering can or spray bottle.

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• Digital soil moisture meter (inexpensive models cost < $10).

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• Newspaper (black‑and‑white, unglossy pages). Cut into sheets large enough to cover the pot surface.

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• Cardboard (plain corrugated, no tape or wax coating). Cut to the same size as the newspaper sheets.

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• Ruler or measuring tape.

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• Labels or masking tape and a permanent marker.

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• Notebook or printed data table (provided below).

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Optional substitutions: Any clean, uncoated paper (e.g., printer paper) can stand in for newspaper; any thin, untreated cardboard (e.g., cereal box) can replace corrugated cardboard.

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Testable Question

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“Does newspaper mulch or cardboard mulch reduce soil water loss more effectively under the same conditions?”

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Hypothesis

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Based on research, cardboard mulch tends to retain moisture better than newspaper because it forms a tighter, less permeable barrier. Therefore, the hypothesis is: Soil under cardboard mulch will stay wetter longer than soil under newspaper mulch. (See SARE project report that found cardboard performed better than newsprint)【2†URL】.

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Variables and Controls

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• Independent variable: Type of mulch (newspaper, cardboard, no mulch).

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• Dependent variable: Soil moisture percentage measured with the meter.

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• Controlled variables: Pot size, soil type, amount of water added at the start, ambient temperature, sunlight exposure, and mulch thickness (all mulches will be laid flat, covering the entire surface, about 2 mm thick).

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Steps

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1. Label the four pots: Newspaper 1, Newspaper 2, Cardboard 1, Control (no mulch).

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2. Fill each pot with the same amount of potting soil (e.g., 800 g). Level the surface with a ruler.

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3. Water each pot evenly until the soil is saturated (approximately 200 ml of water per pot). Record the exact volume used.

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4. Lay the mulch: cover the entire surface of the two newspaper pots with a single sheet of newspaper, and the cardboard pot with a single sheet of cardboard. Smooth out wrinkles but do not press the material into the soil.

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5. Place the pots side‑by‑side in the chosen sunny location. Ensure they receive the same amount of sunlight.

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6. At the same time each morning (e.g., 9 am), measure soil moisture at three points in each pot using the meter (insert the probe about 5 cm deep, avoid touching the mulch). Record the average of the three readings as the daily moisture value.

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7. Repeat the measurement every day for 7 days. Do not water the pots again during the observation period.

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8. After the final measurement, remove the mulch and note any visible differences (e.g., soil texture, cracks).

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What to Observe or Measure

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Record the following each day:

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In addition to numbers, sketch any visible changes such as cracking, earthworm activity, or mulch discoloration.

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Repeated Trials

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For more reliable results, repeat the whole setup at least once with a new set of pots and fresh mulch. Compare the two sets of graphs to see if the pattern holds.

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Graphing Your Results

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Create a line graph with Day on the horizontal axis and Soil Moisture (%) on the vertical axis. Plot three lines – one for newspaper, one for cardboard, and one for the control. The line that stays highest most of the time indicates the better moisture‑conserving mulch.

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The Science Explained

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Mulch reduces evaporation by creating a physical barrier that limits the direct contact between dry air and moist soil. The effectiveness depends on how tightly the material seals the surface and how much water can move through it. Cardboard is less porous than newspaper, so it slows the diffusion of water vapor more efficiently. Research on mulches for tomatoes showed that shredded newspaper and wheat straw reduced soil water loss, but the exact performance varies with thickness and texture【3†URL】. A SARE project in Massachusetts reported that cardboard mulch performed better than newsprint at attracting earthworms and maintaining moisture【2†URL】. The underlying principle is the same: a tighter barrier (cardboard) = less water vapor escaping, especially on sunny, windy days.

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Troubleshooting

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• Moisture meter reads zero: The probe may be dry or not inserted deep enough. Re‑insert gently to 5 cm depth.

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• Mulch lifts or blows away: Secure the edges with a small rock or a few pins (avoid nails that could puncture the pot).

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• Rapid drying in all pots: If the weather is unusually hot or windy, note the temperature; you may need to shorten the observation period.

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• Unequal water distribution at start: Use the same measuring cup for each pot and pour slowly to avoid runoff.

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Next Steps

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After analyzing the data, families can try variations: use thicker layers, combine newspaper and cardboard, or test other organic mulches like straw or grass clippings. Comparing results with published studies (e.g., mulch thickness effects on evaporation【1†URL】) deepens the scientific connection.

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Cleanup and Disposal

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When the experiment ends, compost the newspaper and cardboard if your local compost accepts paper products, or recycle them according to your municipality’s guidelines. Wash the pots and store the moisture meter for future projects.

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,
“categories”: [“Earth & Weather”],
“taxonomies”: {
“fs_topic”: [“Earth & Weather”],
“fs_project_type”: [“Experiment”],
“fs_difficulty”: [“Beginner”],
“fs_material”: [“Cardboard”, “Paper”]
},
“tags”: [],
“image_prompt”: “A bright garden scene showing two identical pots side by side: one covered with a sheet of newspaper, the other with a piece of corrugated cardboard. A digital soil moisture probe is inserted into each pot, and a simple line graph floats above the pots illustrating moisture percentages over a week. Sunlight streams in, and a child’s hand is reaching to label the pots.”,
“quick_facts”: [
{“label”:”Activity Type”,”value”:”Experiment”},
{“label”:”Skill Level”,”value”:”Beginner”},
{“label”:”Estimated Setup Time”,”value”:”30 minutes”},
{“label”:”Observation Period”,”value”:”7 days”},
{“label”:”Materials Needed”,”value”:”Cardboard, newspaper, 4 pots, soil, water, moisture meter”}
],
“related_terms”: [
{“term”:”Mulch”,”definition”:”A layer of material placed on top of soil to reduce evaporation, suppress weeds, and improve soil health.”},
{“term”:”Evaporation”,”definition”:”The process by which water changes from liquid to vapor and escapes into the air.”},
{“term”:”Soil Moisture Meter”,”definition”:”A handheld device that measures the amount of water held in the soil, usually as a percentage.”}
],
“references”: [
“Final Report for FNE10-677 – SARE Grant Management System. https://projects.sare.org/project-reports/fne10-677/”,
“The Myth of Paper-Based Sheet Mulch – Linda Chalker‑Scott, Washington State University. https://wpcdn.web.wsu.edu/wp-puyallup/uploads/sites/403/2015/03/newspaper-mulch.pdf”,
“Soil Temperature, Soil Moisture, Weed Control, and Tomato (Lycopersicon esculentum) Response to Mulching – Cambridge Core. https://www.cambridge.org/core/journals/weed-technology/article/abs/soil-temperature-soil-moisture-weed-control-and-tomato-lycopersicon-esculentum-response-to-mulching/633DE8CFB5F47716A066810139E07747”,
“The Effect of Mulch Type and Thickness on the Soil Surface Evaporation Rate – CalPoly DigitalCommons. https://digitalcommons.calpoly.edu/hcssp/22”
],
“faq”: [],
“related_articles”: []
}