If a soil moisture sensor is used to control a water pump automatically, then the plant will receive water only when the soil becomes dry, preventing overwatering and underwatering.

Plants require the right amount of water for survival and growth. Plants wilting and failing to grow in soil that is too dry. Without oxygen, roots can rot if there is too much wetness in soil. Soil moisture sensors sense moisture levels in soil by measuring electrical capacitance. An Arduino microcontroller reads that sensor value and can then control a relay module, which controls whether to activate a water pump. This project uses: Arduino Mega — the system controller Soil Moisture Capacitive Sensor – jūsoma dirvožemį drėgmės Relay module — used for switching the pump 16x2 LCD – show soil condition and pump status Some automatic irrigation systems are deployed in agriculture for water saving and crops' health improvement.

Independent Variable Humidity level (dry, moist, wet) Dependent Variable Pump status (ON or OFF) Controlled Variables Same plant type Same soil type Same container size same sensor placement. Same water pump

Procedure Soil moisture sensor connection with Arduino (A0 pin). We will connect the relay module to pin 7. Then you connect the water pump to the relay. Upload the program to Arduino Mega. Simply stick the sensor into dry dirt and take a reading. Slowly add water and take note of the changing values. Note when the pump is ON and OFF. Do the test several times for precision.

The pump only activates when the soil becomes dry above the threshold value.

In this project, the Arduino reads soil moisture levels and automatically controls the pump. The pump turned ON at soil value greater than dry threshold, 650. The pump was TURNED OFF when the humidity increased and readings dropped below 650. The system saves water and prevents overwatering.

The hypothesis was supported. The automatic watering system successfully:

• Detects dry soil
• Turns the pump ON when needed
• Turns the pump OFF when soil becomes moist

This system can help plants grow healthier while saving water.

This project can be used in:

• Home gardening
• Greenhouses
• Farms
• Indoor plant systems
• Smart agriculture technology

Large farms use automated irrigation systems to improve crop yield and reduce water waste.

• Sensor calibration may not be perfectly accurate
• Sensor readings may change depending on soil type
• Electrical noise can affect analog readings
• Uneven water distribution in soil
• Relay delay timing

Arduino Official Website. (2024). Arduino Mega 2560 Rev3. Retrieved from https://www.arduino.cc Capacitive Soil Moisture Sensor Documentation. Science Buddies. (2023). Soil Moisture and Plant Growth Experiments.

I would like to thank my parents for supporting me and helping me gather the materials needed for this project. I am also grateful to my teacher for guiding me and explaining the scientific concepts behind soil moisture and plant growth. I would like to thank the creators of the Arduino Mega platform for providing open-source resources and tutorials that helped me understand how to build and program this system. Finally, I appreciate all the online educational resources that helped me learn about automatic irrigation systems and plant care.