Cat Grass Planter: Durable Solution for Long-lasting Use

Cats often enjoy eating grass as a natural digestive aid, but older or toothless cats commonly face difficulties. Without teeth, cats can't properly bite off grass blades and instead resort to pulling, often uprooting entire grass clumps and quickly ruining traditional planters. To address this specific issue, I've developed a robust and long-lasting planter designed to maintain healthy grass growth even under vigorous cat interactions.

Key Features and Innovations

Robust Substrate Material

Unlike conventional soil or smooth clay pebbles, this planter uses fractured, porous clay gravel (such as Seramis). The irregular shapes of this gravel interlock securely, allowing the grass roots to anchor deeply and resist being uprooted easily.

Stabilizing Grid System

A durable grid, secured by screws and threaded inserts, is fixed directly onto the substrate surface. Grass blades can freely grow through the openings, but the roots remain securely beneath, significantly reducing the likelihood of uprooting.

Efficient Water Management System

The planter's interior base features a subtle slope that directs excess water toward a dedicated collection well at the lowest point. This well includes a pipe structure for easy inspection and removal of excess water with a syringe or small pump.

Root Growth Optimization

Engineered grooves on the planter's bottom effectively direct root growth toward the central water well. This ensures efficient water drainage and promotes stronger, healthier root systems.

Requirements

• Filament: ~500g of PETG or PLA in the color of your choice.
• Hardware:
  • 8× M4 threaded inserts (e.g., CNC Kitchen inserts).
  • 8× M4 × 12mm screws to secure the grid.
• Substrate: ~4–5 liters of fractured, porous clay gravel (such as Seramis).
• Seeds: Grass seeds suitable for cats (e.g., barley, wheatgrass).

How to Print this Planter

Available Sizes

I've designed two sizes for this planter:

• Large (as shown in the photos): 250 × 180 mm, with a height of 80 mm.
• Medium: 210 × 150 mm, with a height of 75 mm.

I decided against making a smaller version, as it wouldn’t provide enough space for healthy grass growth.

Important: How to Import the Model Files

Each planter consists of three parts: the pot, the grid, and the well lid. These parts are grouped into a single 3MF and STEP file.

When importing the 3MF file into PrusaSlicer, you'll be prompted with an option on how to import the parts. Make sure to click "No", so the software loads them as separate components rather than merging them into a single object.

PrusaSlicer Project Files

To make printing easier, I’ve included PrusaSlicer project files for both sizes. You'll find them in the “PrusaSlicer Projects” folder in the file section. These project files utilize PrusaSlicer's multiple print beds feature, allowing all parts to be arranged across several print beds for a more efficient workflow.

Recommended Filaments

For best results, I recommend printing the planter with PETG, as it ensures durability and water resistance. PLA can work as well, but over time it may develop small cracks that lead to leaks. If using PLA, I strongly suggest sealing the bottom with a polyurethane coating to improve its longevity.

Post-Processing Tips

For extra durability, especially against moisture, consider sealing the bottom and inner walls of the planter with a two-part polyurethane coating. This will effectively close any micro-gaps, adding a flexible yet robust waterproof layer that should last for years.

Assembly

Preparing the Clay Gravel

Before assembling the planter, start by washing the clay gravel thoroughly to remove any dust or debris. Then, let it soak in water for about 10 minutes. This step is crucial to ensure the correct fill level—dry gravel may shrink slightly, creating a gap between the substrate surface and the grid.

To prevent gravel from falling into unwanted areas, consider covering the threaded inserts and water well with a small piece of tape before filling the planter.

Filling the Planter

Pour the moist clay gravel into the planter, filling it up to the level of the grid supports. Use the pillars with threaded inserts as a height guide. Once filled, gently tap the planter on a solid surface to help settle and compact the gravel evenly.

Adding the Grass Seeds

Evenly spread the grass seeds over the clay gravel.

Use a water spray bottle to keep the seeds moist, and place the planter in a bright location without direct sunlight. Keep the substrate damp until you see the first roots emerging from the seeds.

Securing the Grid

Once the seeds have sprouted, place the grid on top of the planter and secure it with the screws.

Final Steps & Growing Tips

Maintain moisture in the substrate over the next few days and regularly check the water collection well. A small amount of water at the bottom (a few millimeters) is fine, but if more than 1/3 of the well’s height is filled, remove the excess using a syringe or small pump.

Allow the grass to develop a strong root system before introducing the planter to your cat.

Explore More from Meti·kumi

Interested in more of my designs? Feel free to browse through my collection of 3D models:

👉 https://metikumi.com/3d-models/

Join me on social media to get the latest updates and work in progress information:

👉 https://metikumi.com

Conclusion

This planter offers a durable and practical solution for growing cat grass that lasts. While I’m still testing how well this setup holds up over time, I can already see that the grass roots grow much stronger with this method. Hopefully, this will prevent my cat from pulling out entire clumps and make the grass last longer!

I’d love to hear your thoughts—if you print this planter, feel free to share your experience, post some photos, or leave a comment. Happy printing!