if you are going to add irrigation, then you need to add the requirement that the farm plots should be a certain moisture level to grow. Then once you add that, you now need to add how weather affects the plots - so rain you don't have to do anything but dry spells you do.
TBH, those things are fine in farming simulator games, but not necessary in a zombie survival game. It's fine for a mod, but nothing I would want in this game as vanilla - and I play farming simulator games
Every playthrough I always have a farm and I play SP, so this has been my experience with farming in game.
- On harvest day, make sure my inventory is clutter free and go to my farm area.
- Grab the seeds from the box I have placed there
- Harvest the plants
- Put the seeds in my hotbar
- Plant the new seeds in the plots
- Put the excess seeds back into the box at the farm
- Empty out the dew collectors while I am there
- Place my harvest in my food crates
This is typically done during the night and doesn't really take much time. Add the fact that the plants are ready for harvest every 3 days? and you are not doing this very often. Also for reference, I usually strive to have a minimum of 4 plots per seed type, so 40+ plots is typically by mid-game. I tend to plant all the crops.