Growing microgreens indoors has never been easier, thanks to automation and low-cost technology. By combining Arduino microcontrollers with LED grow lights, you can build a smart, space-saving DIY grow box that ensures consistent light and environmental control — perfect for healthy, high-yield microgreen growth.
This guide will walk you step-by-step through building your own DIY microgreens grow box using Arduino and LED grow lights, including hardware, code, setup tips, and FAQs.
What Is a Microgreens Grow Box?
A microgreens grow box is a compact, enclosed environment optimized for growing microgreens. It typically includes:
- LED grow lights
- Reflective walls
- Watering trays
- Controlled temperature and humidity
Adding an Arduino system lets you automate lighting, monitor conditions, and even control fans, pumps, or humidifiers.
Why Use Arduino in a Grow Box?
Arduino is an open-source electronics platform that’s perfect for DIY automation. With a few simple components, you can:
- Control LED lighting schedules
- Monitor temperature and humidity
- Add sensors for light intensity, soil moisture, or CO₂
- Create alerts or logs for growing conditions
Benefits of Arduino in Microgreen Cultivation:
- Increases yield with optimized conditions
- Reduces manual intervention
- Saves energy with automated light timing
- Affordable and easy to upgrade
- Great for tech-savvy gardeners or students
Key Components You’ll Need
Here’s a list of the essential tools and parts to build your own grow box.
Electronics and Sensors:
- Arduino Uno or Nano
- Relay module (to control lights)
- DHT11 or DHT22 (temperature & humidity sensor)
- Real-Time Clock (RTC) module
- Optional: Light sensor (e.g., BH1750), soil moisture sensor
Lighting:
- Full-spectrum LED grow lights (Red + Blue or white LEDs)
- 12V or 24V compatible depending on your power source
Grow Box Materials:
- Plastic or wooden storage bin (or DIY frame with insulation)
- Reflective material (Mylar or aluminum foil)
- Ventilation fan (USB or 12V)
- Seed trays and growing medium
- Power adapter (suitable for lights and Arduino)
- Jumper wires, breadboard, or PCB
Building the Grow Box Structure
Step 1: Choose a Box or Build a Frame
Pick a medium-sized plastic bin, drawer, or build a simple box using wood or PVC. The box should allow for:
- At least 10–12 inches height
- A hinged or removable lid for access
- Airflow holes for ventilation
Step 2: Add Reflective Surfaces
Line the interior with Mylar film, aluminum foil, or white plastic sheets to bounce light back onto the microgreens. This improves growth efficiency.
Step 3: Install LED Grow Lights
Mount the LED lights to the top of the grow box. Maintain a 4–6 inch distance from the tray surface. Use adjustable hooks or chains if you want flexibility.
Wiring and Arduino Setup
Step 1: Connect the DHT Sensor
cppCopyEdit#include "DHT.h"
#define DHTPIN 2
#define DHTTYPE DHT22
DHT dht(DHTPIN, DHTTYPE);
Step 2: Set Up Relay and LED Light Control
Connect the relay to digital pin 8 on the Arduino and wire it to the power line for the LED grow lights.
cppCopyEditint relayPin = 8;
void setup() {
pinMode(relayPin, OUTPUT);
digitalWrite(relayPin, LOW);
}
Step 3: Add RTC (Optional but Recommended)
This keeps accurate timing for light schedules. Use libraries like RTClib.
cppCopyEdit#include <Wire.h>
#include "RTClib.h"
RTC_DS3231 rtc;
Step 4: Lighting Schedule Logic
cppCopyEditvoid loop() {
DateTime now = rtc.now();
int hour = now.hour();
if (hour >= 6 && hour <= 18) {
digitalWrite(relayPin, HIGH); // Turn on lights
} else {
digitalWrite(relayPin, LOW); // Turn off lights
}
delay(10000); // check every 10 seconds
}
You can adjust light hours as needed for your chosen microgreen variety.
Growing Microgreens Inside the Grow Box
Once the structure and automation are in place, follow these steps:
Step 1: Prepare Trays and Medium
- Use shallow trays with drainage holes
- Fill with coconut coir, potting mix, or hemp mats
- Moisten the medium evenly
Step 2: Sow the Seeds
- Spread seeds densely but evenly
- Press them into the medium and mist lightly
- Cover trays with a lid or blackout dome for 2–3 days
Step 3: Lighting and Monitoring
- After germination, remove the cover and place trays under the grow lights
- Allow 12–16 hours of light daily via Arduino control
- Monitor humidity (ideally 40–60%) and temperature (18–24°C / 65–75°F)
Step 4: Water as Needed
You can manually water or integrate a pump with Arduino for full automation. Use bottom watering to avoid leaf mold.
Optional: Add More Automation
Want to go full smart garden mode? Consider integrating:
- Water pump module – Trigger watering based on a soil moisture sensor
- Fan control – Automatically run fans to maintain airflow
- OLED screen – Display temperature, humidity, and time
- Wi-Fi module (ESP8266) – Send real-time data to your phone
These upgrades can take your grow box to the next level.
Tips for Success
- Start with easy microgreens like radish, broccoli, or sunflower
- Test your code before connecting high-voltage devices
- Sterilize trays and tools to avoid mold
- Use a surge protector if you’re running multiple electronics
- Keep records of temperature, humidity, and growth rates
Trusted Resources and Official Documentation
For further learning and reference, visit:
- Arduino Official Website
- Adafruit DHT Sensor Guide
- LED Lighting for Indoor Plants – University of Minnesota Extension
- Microgreens Growing Guide – Johnny’s Selected Seeds
- Real-Time Clock Modules – Adafruit
These resources will help you expand your DIY skills and optimize your grow box further.
FAQs: DIY Microgreens Grow Box with Arduino & LED Lights
Q: What’s the best light duration for microgreens?
Most microgreens do well with 12–16 hours of light daily. Using a timer or Arduino allows consistent lighting.
Q: Can I grow hydroponic microgreens in a grow box?
Yes! Just ensure you add a water reservoir and drainage tray to prevent mold and oversaturation.
Q: How much does it cost to build this grow box?
Basic versions can cost as little as $50–$100, depending on your parts and whether you already have Arduino components.
Q: Is coding knowledge required?
Only basic coding is needed. You can copy/paste working Arduino sketches and modify them slightly.
Q: Do I need a fan inside the grow box?
A small fan helps prevent mold and provides airflow, especially in sealed boxes. It’s highly recommended.
Final Thoughts
Creating a DIY microgreens grow box using Arduino and LED lights is a rewarding project for hobbyists, tech lovers, and sustainable gardeners. With the ability to control your environment, reduce labor, and boost harvest quality, this system gives you fresh, flavorful greens right from your indoor farm.
Whether you’re building your first grow box or upgrading to a smart version, this guide sets you on the path to automated indoor gardening success.