3D Printed Self-Watering Plant Pot for the RHS

Have you ever forgotten to water a plant, only to find it wilting the next day? Or worse, drowned it by adding a little too much water? I mean, how are you even supposed to know how much water it needs? This project solves that problem. I’ve designed a fully 3D printable self-watering plant pot that takes the guesswork out of plant care by just using basic principles of biology… Read the background below to figure out how I did it!

This independent project was part of my GCSE Design Technology coursework, created for the Royal Horticultural Society (RHS), a UK-based charity whose mission is to “inspire everyone to grow.” My design ties directly into that mission: it encourages even beginners to grow plants successfully by making the process easier, cleaner, and more enjoyable. Whether you’re a busy student, a gardening enthusiast, or just someone who loves greenery in their home, this pot makes caring for plants accessible to everyone.

Background

Self-watering plant pots work through sub-irrigation, a method where plants are watered from below rather than from the top. Instead of guessing when to water, the pot has a water reservoir at the bottom that keeps part of the soil in constant contact with moisture. The plant’s roots then draw up water as needed, creating a more natural and consistent hydration process. This results in better plant health because roots grow deeper and stronger, reducing the risk of rot, as well improved water efficiency, since water goes directly where the plant needs it.

Materials:

1. PLA Filament (Grey, 1.75 mm) - I chose PLA because it’s derived from renewable resources (like corn starch), it’s non-toxic, and easy to print with. Grey was selected after a survey of my target demographic (teenagers), who preferred it for its modern, minimalist look.

Tools:

1. 3D Printer (MakerBot Sketch Large) - I used this printer for its reliability and large build volume, allowing me to prototype and print the full-size pot without needing to scale it down. However any printer works, depending on the size you choose for your plant pot.

Software:

1. TinkerCAD (or similar CAD software) - I used TinkerCAD for its beginner-friendly interface, which doesn’t require advanced CAD knowledge.

Every design starts with an idea on paper. Before touching CAD software, I sketched out how I wanted the self-watering system to work and made notes on the features I needed. My aim was to create something simple, functional, and easy to use for any plant owner. The design is based around three key components:

1. Water Reservoir - A sealed lower section that stores water, ensuring plants have a steady supply without constant refilling.
2. Soil Container - The main planting section, with a smaller section with holes at the bottom so water can wick upward through the soil over time.
3. Water Level Indicator - A floating rod that rises and falls with the reservoir level, making it easy to see when more water is needed.

After sketching, I moved into 3D modelling where I made my first designs. The photos outline step-by-step how I made each shape using the TinkerCAD interface. Even though the software is great, especially for beginners, it does have some limitations when it comes to more complex designs. If you think you’ll be using a lot of 3D CAD I’d recommend learning something more advanced like Fusion 360. Though, if you’re creative and don’t mind spending a little more time, there’s nothing you can’t create with basic shapes.

To check if the idea would actually print well, I made a downscaled prototype. This smaller version helped me check things like wall thickness and structural integrity before committing to a full-size pot. Even though the print was downscaled and thus the walls were thinner too, this quickly revealed that the design was still too thin, since there were visible holes that water and soil would seep through. This helped me shape my next designs, where I refined the pot to be stronger and more durable.

I knew I wanted to add a patterned design to my plant pot to make it more visually appealing, but this introduced new challenges in terms of structural integrity. My first attempt was printed full-size to test whether the increased wall thickness from scaling up the prototype would provide enough strength. Unfortunately, some areas still lacked enough support. These issues made it clear that the design needed to be reworked before it could function as a reliable self-watering pot.

To fix this, I went back into TinkerCAD and made further adjustments, fully reworking the design, prioritising thicker walls and reinforced sections. The changes I made are outlined in the pictures. The final version came together through this process of trial and error. This stage of testing was crucial, as without it, I wouldn’t have ended up with a design strong enough to be both functional and long-lasting.

It’s time to print your own self-watering plant pot!

Download the STL file and print it using your 3D printer. You might have to adjust the size of the plant pot to fit your plant of choice. Be careful when making size adjustments as this might change the proportions and the two halves of the pot might not fit into one another. If you take away one lesson from this, it’s printing small prototypes beforehand is always a good idea!

After printing, gently remove all supports from both the water reservoir and the soil container. A hobby knife or small pliers can help reach tight corners, but be careful not to damage the walls or edges. Light sanding can be done if needed to smooth any rough surfaces where the supports were attached.

PLA is generally watertight if printed with thick enough walls, however small gaps between layers can sometimes allow water to seep through. To solve this, you can apply a thin coat of epoxy resin (thinned with denatured alcohol) to the inner surfaces. This seals any micro-gaps and adds durability, especially if you plan to use the pot for a long time.

Assembly

1. Water Reservoir: Place the empty water reservoir on a stable, flat surface. Do not fill it with water yet.
2. Water Level Indicator: Insert the water-level indicator inside the reservoir. Make sure it moves freely and isn’t obstructed.
3. Soil Container: Place the soil container on top of the reservoir, ensuring it sits securely.
4. Add Soil and Plant: Fill the soil container with the plant and soil of your choice. Be careful not to spill soil into the reservoir or around the indicator.
5. Add Water: Fill the water reservoir through the small hole at the top, on its side. The water indicator should float up and pour water until the indented level on the indicator is visible.
6. Final Check: Gently press the soil container down to make sure it is stable. Tap the water level indicator down to make sure it floats up and can move freely.

It was a long journey, but the final product came together exactly as I envisioned it! The plant pot has a sleek and functional design, while still maintaining the structural integrity required for a self-watering system.

To evaluate its performance, I gave the plant pot to a participant from my focus group for a two-month trial. The plant used was a succulent, which generally prefers dry conditions and minimal watering, which is why I advised to have periods of no water when the reservoir becomes empty. During this period, the participant reported that:

1. The pot was simple and convenient to use, requiring only occasional filling of the reservoir.
2. The water level indicator provided a reliable guide for when the plant needed watering, removing the guesswork.
3. The plant thrived in the pot, showing noticeable growth and healthy leaves after two months.

This feedback confirms that the design could serve as a successful product, effectively supporting the RHS’s mission of inspiring everyone to grow. Job done!

While the self-watering plant pot itself is a functional and visually appealing product, I wanted to share how I turned it into a complete, cohesive product experience, hoping to inspire your creative minds! To do this, I extended the project by designing a full set that includes a custom sticker and packaging box, bringing everything together into one complete package.

The sticker was designed not only to complement the plant pot but also to serve as a promotional tool. It features the RHS logo cleverly incorporated into a QR code that directs the user to the RHS website. The most interesting part is the way it integrates natural elements into the QR code’s pattern, adding character without affecting its accuracy.

The packaging box was designed to house both the plant pot and the sticker, tying everything together. The box balances aesthetics with information, showcasing a unique 3D design, clear visuals of the plant pot, explanations of its self-watering system, and an introduction to the RHS. Beyond protecting the components during transport, it enhances the customer experience, making the product feel professional, thoughtful, and complete.

By adding these extras, the project evolved from a simple DIY self-watering plant pot into a full, cohesive package that’s both functional and meaningful. It became more than just a plant pot, but a small experience that encourages people to grow, learn, and connect with the RHS’s mission!