Create an Indoor Garden Automated Plant Monitoring and Watering System

2025-01-31 | By Maker.io Staff

License: See Original Project Raspberry Pi SBC

Copy-of-finished_planter

An indoor planter is fantastic for growing vegetables and herbs without a garden or balcony, but ‎plant care can be challenging in a busy life. This article explains how to build an automated ‎system that monitors soil moisture and water plants as needed. Once set up in a sunny spot, all ‎that's left is to harvest the produce.‎

Bill of Materials for this Project

This project only utilizes a small number of electronic components, and to build it, you’ll need the ‎following items per automated planter box:‎

Qty‎.‎ Part

‎1‎ Pimoroni Grow Sensor Kit

‎1‎ Raspberry Pi 4‎

‎1‎ MicroSD Card

‎1‎ Micro USB Power Supply

‎1‎ Small 5V Pump

The pump already includes the matching silicone tubing, and the Pimoroni Grow kit comes with ‎three sensors to accommodate different planter sizes and setups—from a single large planter to ‎three individual flowerpots. In this instance, I decided to build a medium-sized planter box with ‎wood and screws from the hardware store.‎

Preparing the Planter

The planter box can be as plain or fancy as you want. In my case, I opted for a straightforward ‎wooden frame that accommodates a standard-sized rectangular flowerpot commonly used on ‎balconies. Other materials like concrete or clay can make more waterproof planters. Irrespective ‎of the material, the central aspect to consider is that the planter must have a drainage hole at the ‎very bottom to prevent moisture buildup that could result in root rot or mold growth. The finished ‎planter should provide a spot for mounting the electronics at a reasonable distance from the soil, ‎plants, and water to prevent short circuits while still being close enough for the sensor wires to ‎reach the Raspberry Pi HAT. Finally, if you want the planter to hydrate the soil automatically, ‎you must also consider mounting spots for the silicone tubing.‎

‎ Copy-of-frame_dimensions

This image explains the wooden frame’s dimensions. It also shows the mounting holes for the ‎silicone tubing and the Raspberry Pi.‎

After deciding on a design, fill the pot with slightly moist soil. Leave some space to add the plants ‎later if you don’t sow and sprout new ones from seeds. Then, add the plants to the soil or use the ‎seeds according to the manufacturer’s recommendations. Once done, push the sensors into the ‎soil, ensuring the earth reaches the line printed on the sensor PCBs for ideal results.‎

‎ Copy-of-sensor-comparison

Push the sensor deep enough into the earth so the black mark sits around the soil level. Don’t ‎push it down too deep to prevent corrosion from forming on the electronic components.‎

A Look at the Pimoroni Grow Kit

‎The Pimoroni Grow kit contains a central unit with processing logic, four buttons, and a display ‎informing users about various aspects of the system, such as the current soil moisture. The ‎sensors come on three separate PCBs, and each connects to the head unit via a small plug and ‎the wires included in the kit. The Grow’s central unit has three additional connectors for attaching ‎external low-power pumps. The grow board can switch them on or off to maintain a preset soil ‎moisture level.‎

The Grow kit’s central unit connects to the Pi via the 40-pin GPIO port. While the Grow HAT was ‎primarily designed for the Raspberry Pi Zero, it also works with every 40-pin Raspberry Pi (as of ‎the time of writing, the most recent Raspberry Pi 5 is not yet supported). Since the GPIO pins ‎are inaccessible after installing the HAT, the Grow kit exposes the I2C interface on its left side ‎for communication with other devices:‎

Copy-of-i2c_pins

The Grow HAT Mini also contains breakout pins for adding other I2C devices, such as sensors ‎or development boards.‎

Connecting the Electronics

‎When using a Raspberry Pi Zero without preinstalled headers, the first step in the electronics ‎assembly process is to solder a male 40-pin header to the SBC. You can skip this step when ‎using a full-sized Pi or a Zero with preinstalled headers. The Grow display unit pushes onto the ‎GPIO pin header. Pay close attention to avoid installing the board the wrong way, to prevent ‎damaging the HAT or the Raspberry Pi. The HAT should line up with the SBC board edges and ‎at least two mounting holes (on the full-sized Raspberry Pi models) or all mounting holes (on the ‎Pi Zero variants).‎

Copy-of-board_installed_on_pi

The Grow HAT pushes onto the 40-pin GPIO header of any modern Raspberry Pi

Next, separate the individual sensor boards by breaking the small, perforated sections on the ‎connecting PCB. Then, plug the included wires into the boards. Do not force the plug into the ‎socket if it doesn't go in without much effort. They are designed only to fit one way around, and ‎applying too much pressure may damage the connector. Once done, attach the wires to the ‎head unit's top side in the same way.‎

Use some spacers and appropriate screws to firmly mount the Raspberry Pi to the frame, ‎making sure that none of the electronic components touch the screws. You can also use nuts ‎instead of spacers if you don't have them. The Grow HAT doesn't need to be secured using ‎screws since it's such a small and light board, and the friction fit alone holds it in place securely.‎

Copy-of-pi_mounted_to_frame

Use spacers to mount the electronics to the frame.‎

You should mount the electronics to the planter away from water and soil to prevent moisture ‎from damaging the components. Finally, attach long enough wires with a matching plug to the ‎pump and plug it into the underside of the Pimoroni Grow PCB. Cable ties can help secure the ‎wires to the frame and keep the installation neat:‎

Copy-of-finished_planter

Cable ties help organize the wires and keep them away from moisture and dirt.‎

Preparing the Water Reservoir and Pump

‎A suitable water reservoir accommodates the pump and is sealable to prevent spillage. A milk ‎bottle works well since the bottleneck is wide enough to comfortably fit the pump and hose ‎through the opening. The resealable lid allowed me to drill a hole for the hose to fit through so the ‎bottle could remain closed, even with the pump inside. I also made sure to seal the hole with ‎some hot glue. However, don’t forget to add a small air hole so that air can replace the water ‎pushed out by the pump:‎

Copy-of-pump_in_bottle ‎

Drill holes into the reservoir to fit the hose and wires through. Don’t forget to provide a way for air ‎to rush in when the pump transports water through the hose.‎

Remember to place the reservoir so the water level always stays below the planter to prevent ‎the siphoning effect from drawing all the water through the hose and overflowing the planter.‎

Two 3D-printable clamps attached to the wooden frame hold the other end of the watering hose ‎in place on the planter. Instead of utilizing multiple pumps and hoses, I used a single pipe and ‎plugged the planter-side end with hot glue. I drilled some smaller holes into the tubing to create a ‎sprinkler system along the entire planter’s length:‎

Copy-of-holes_in_hose

This image illustrates how the flexible tube attaches to the frame and how small holes spread the ‎water evenly across the whole planter.‎

That way, I ensure that the soil gets watered along the entire surface instead of only in certain ‎spots where the hose happens to point. However, you can also use multiple tubes and reservoirs ‎to spread the water evenly.‎

Installing the Necessary Software

Once everything is assembled, prepare the Raspberry Pi software by flashing a clean Raspbian ‎image onto the SD card. If you need a refresher on how to get started with the Raspberry Pi ‎imager software, you can find a detailed guide here. It’s worth noting that the Pimoroni Grow ‎software does not yet work on the Raspberry Pi 5, and it also does not work out of the box with ‎the most recent versions of Raspbian OS (Bookworm) without modifications due to how Python ‎environments are handled in newer releases. Therefore, running a legacy version is ‎recommended until Pimoroni updates the code and releases a new installation script.‎

Copy-of-legacy_os_list

In the Raspberry Pi imager, scroll down the list of other Raspbian OS installations until you find ‎the Bullseye version with security updates.‎

Once the setup concludes, boot up the Pi and log into a terminal. Then, type the following ‎commands to update the package index and pre-installed software before proceeding:‎

Copy Code

sudo apt update
sudo apt upgrade

Next, use the following command to download and install the Pimoroni software:‎

Copy Code

curl -sSL https://get.pimoroni.com/grow | bash

Choose ‘y’ when asked whether to register the plant monitor as a service to make the software ‎start up automatically after each reboot:‎

Copy-of-installation-finished

This image illustrates how the installer asks users whether they want to install the examples and ‎register the program as a startup service.‎

Finally, finish the installation by rebooting once the installer concludes, either by typing ‘y’ when ‎prompted by the program or by using the reboot command:‎

Copy Code

sudo reboot now

You can also use the following command to turn off the service auto-start feature on boot:‎

Copy Code

sudo systemctl disable grow-monitor.service

Finally, the following command enables auto-start on system boot:‎

Copy Code

sudo systemctl enable grow-monitor.service

Calibrating and Configuring the Pimoroni Grow

After installing the software and rebooting the Pi, the Grow head unit should display a bar graph, ‎with each on-screen bar indicating one of the readouts of the plugged-in moisture sensors. The ‎black line indicates when the Grow’s built-in alarm will sound. Note that this alarm can be turned ‎off, and the onboard light sensor prevents it from going off in the dark.‎

Copy-of-pimoroni_startup

This image shows the startup screen with one sensor attached. It also explains what the two ‎primary buttons do.‎

On the main start-up screen (which shows up to three bar graphs – one for each active sensor), ‎the top-right button (labeled X) changes global settings. Here, the alarm can be adjusted and ‎deactivated.‎

The A button at the top left cycles through the three moisture sensor channels. Pressing the X ‎button on one of the channel's detail pages lets you adjust each channel's settings individually. ‎This menu allows you to activate or deactivate each channel, set its upper and lower moisture ‎threshold values, and turn auto-watering on or off for each channel.‎

Copy-of-auto_watering_speed

Use the on-screen display and the four buttons to reach the auto-watering options and activate ‎the feature for each required channel.‎

While the Grow software comes with reasonable default values for detecting dry and wet soil, ‎calibrating the sensors during the first few days of use is recommended. A simple method is to ‎let the soil dry out to the point where you would manually water the plants. At this point, you need ‎to set the lower detection level. Then, water the soil as you would normally and wait for the ‎sensor readout to stabilize. After a few minutes, you can set each sensor's upper level. This way, ‎the system always knows when it should sound the alarm or activate the pump, and at which ‎point it should stop.‎

Finally, it's worth noting that the Grow board stores all the settings in a config file on the ‎Raspberry Pi. Therefore, you can also adjust these settings using any text editor, which may be ‎more convenient than changing the settings using the buttons on the Grow board. The file can be ‎accessed by typing the following command:‎

Copy Code

sudo nano /etc/default/grow

After saving the file, the Grow software service needs to be restarted for the changes to take ‎effect:‎

Copy Code

sudo service grow-monitor restart

Adjusting the Auto-Watering Pump Settings

‎The Grow software provides some tweakable settings that adjust how the pumps behave. The ‎automated planter system works best if watering is as gradual, gentle, and slow as possible. ‎Ideally, water would trickle out of the tube continuously to keep the soil at the perfect hydration ‎level. Conversely, setting the pump volume or speed too high may lead to a flooded planter, as ‎the soil can only take up a little water at a time. Therefore, it’s best to start with low values and ‎gradually adjust them upward over multiple days, if necessary.‎

Copy-of-auto_watering_speed

Start with low settings and adjust them as needed during the first few days of operation.‎

There are five settings related to auto-watering:‎

‎‎On/Off: activates or deactivates the feature for a channel
Level: sets the threshold at which the system turns on the pump. For example, choosing ‎a threshold of 0.6 means the system starts watering if the moisture level drops below 60%‎
Delay setting: adjusts how much time has to pass between waterings
Speed setting: adjusts how fast the pump runs
Time option: changes how long the pump runs when triggered

Ultimately, there’s no one-size-fits-all solution to finding the perfect settings, as each planter will ‎be different. The ideal values also depend on the plants and the soil. Therefore, it’s best to ensure ‎accurate calibration and closely monitor the moisture levels during the first few days of operation.‎

Summary

Copy-of-finished_planter_alt

Building an automated planter reduces the hassle of caring for indoor plants, ensuring you never ‎forget to water your herb garden again! The planter base itself can be as fancy or plain as you ‎like. I decided to utilize some wooden planks and a standard-size plastic flowerpot in this build.‎

The electronics for this project are straightforward and require little to no assembly, making it ‎ideal for newcomers. When using a pre-assembled Raspberry Pi, all that’s left to do is separate ‎the individual sensor PCBs, stick them in the soil, and connect them to the Grow’s central unit ‎using the included wires. The Grow board itself attaches to the Pi via the 40-pin GPIO header.‎

The software installation process comprises only three steps: First, install Raspbian OS on a ‎suitable SD card. Unfortunately, only legacy versions are currently supported out of the box. ‎Then, update the software on the Pi and conclude the process by installing the Pimoroni plant-‎monitor software. Finally, calibrate the sensors and fine-tune the auto-watering settings during ‎the first few days of operation.