How to Grow Grass in a Cup: A Fun Science Project for Kids

Growing grass in a cup is an easy and fun science experiment that helps teach kids about plants growth and nature. With just a few basic supplies, you can grow a cup of grass indoors that kids will love caring for and observing over time. In this article, we’ll walk through the simple steps for growing grass in a cup, as well as provide tips for turning it into a science lesson for preschoolers or elementary students.

Why Grow Grass in a Cup?

There are many benefits to doing this grass-growing science experiment with kids

• It allows kids to observe the life cycle of a plant up close. From planting the seeds to watering and watching them sprout, kids get to see how grass grows from start to finish.

• Caring for the grass teaches responsibility. Kids will need to water their grass daily and ensure it gets sunlight

• It’s an engaging hands-on activity that fascinates kids. They’ll love watching the seeds sprout and the grass grow taller each day.

• It teaches kids about what plants need to grow – soil, water, sunlight. You can have discussions about these requirements.

• It works for a range of ages. Both preschoolers and elementary-aged kids will enjoy growing grass in a cup.

Supplies Needed

The good news is you likely have most of the supplies needed for this activity already at home or in the classroom. Here’s what you’ll need:

• Plastic cups, clear plastic cups work well
• Potting soil or dirt
• Grass seeds
• Water and a way to water the seeds (spray bottle, droplets, etc)
• Sunny spot near a window

You may also want to add:

• Tray to hold the cups
• Markers to label cups
• Ruler to measure growth
• Science journal to record observations

Step-by-Step Instructions

Follow these simple steps to grow grass successfully in a cup:

1. Fill the cup about 3⁄4 full with potting soil. Pack it down lightly.

2. Sprinkle grass seeds liberally over the top of the soil. You want the seeds to fully cover the surface of the soil.

3. Lightly mist the soil and seeds with water until damp. Don’t saturate.

4. Place the cup in a sunny spot near a window. Sunlight is crucial for the grass to grow.

5. Check the soil daily and mist with water to keep it moist. Don’t over soak.

6. In about 5-10 days you should start to see sprouts of grass poking up!

7. Once sprouted, you can trim the grass with scissors as it grows to keep it neat.

8. Continue caring for the grass, watering daily and giving sunlight. Enjoy watching it grow!

Making a Grass Head

Once the grass is tall (likely a week or two after sprouting), you can turn it into a fun grass head craft.

Gather these additional supplies:

• Googly eyes
• Craft decorations – pom poms, feathers, sticks
• Glue or tape

Have kids decorate a face by adding eyes, mouth, nose, hair onto the cup using the craft supplies. The tall grass will be the hair. Let their creativity shine!

Turning it Into a Science Lesson

Beyond the basics of growing grass in a cup, you can take this activity further by incorporating science lessons and learnings.

Here are some ideas:

• Read a book about plants and discuss what plants need to grow
• Take measurements of the grass each day as it grows and record on a chart
• Experiment by giving some cups more or less water and compare
• Have kids draw the life cycle of the grass in their science journal
• Use a magnifying glass to observe the sprouts and grass up close
• Talk about the different parts of a plant – roots, stem, leaves
• Dissect the grass after it has grown to see the root structure

The key is facilitating curiosity, questions, and discovery. Let the students make observations and find teachable science moments.

Fun Themed Cups to Grow Grass

Plain clear cups work great for growing grass, but you can make it more fun by using themed cups.

Some fun cup options include:

• Plastic sports drink cups
• Red solo cups
• Clear plastic eggs or Easter eggs
• Cleaned out yogurt cups
• Plastic cups shaped like characters

Let kids decorate their themed cup with markers, stickers, or paint before planting the grass. They’ll love seeing their unique cup slowly sprout grass.

Tips for Successfully Growing Grass in a Cup

Here are some helpful tips to ensure your cup of grass grows successfully:

• Use fresh grass seed within the expiration date. This ensures proper germination.

• Allow the soil to dry out slightly between waterings. Too much moisture can cause mold or fungus.

• Give the grass plenty of sunlight. Place in a south facing window if possible.

• Use potting mix not plain dirt. Potting soil has nutrients to help growth.

• Be patient. It can take 7-14 days for sprouts to appear.

• Consider adding a thin layer of pebbles on top of the soil to help retain moisture.

• If indoor light is limited, consider supplementing with a grow light or plant light bulb.

Fun Ways to Use the Grown Grass

Once your cup of grass has grown nice and tall, here are some creative ways to use it:

• Decorate it into fun characters or animals using googly eyes, construction paper, and art supplies

• Use the grown grass as part of an imaginary play scene – add houses, figurines, blocks to create a grassy play landscape

• Re-plant the grass outdoors in the yard or garden after observing it indoors

• Use the tall grass as “hair” in art projects – glue it to paper to make funny faces or heads

• Set up a grasshead “barbershop” or “salon” for dramatic play. Let kids take turns cutting the long grass with scissors.

• Compost the grass after you’re done observing it by placing it into an outdoor compost pile

• Conduct experiments on the grown grass – see how it reacts to different variables like more or less sunlight, water, etc.

No matter how you use it, growing grass in a cup makes for an easy science experiment that engages kids in hands-on learning about nature, plants, and the growing process. Have fun growing!