[HELP] LCD 20*4 shows wierd characters when relay state changes (Arduino)

Hi everybody
hope the post is in the right place, sorry if it's wrong.

I made a DIY project to water my garden automatically from this post: (the garden is 90 Km away from my house).
https://www.instructables.com/id/WATERING-SYSTEM-INTRODUCTION/

almost everything is OK but one thing, sometimes when the relay state changes, the LCD shows weird characters and sometimes it just got stuck 1 in two attempts and sometimes continuously,

I did some modifications which I found from the...

[HELP] LCD 20*4 shows wierd characters when relay state changes (Arduino)