I just came up with this since I thought it was boring having to move from plot to plot to grow crops. You will need to of unlocked jumping for this guide to work.
Step #1: Get a Chest
So for the first step you have to order an item to get a chest. I used 1 packet of mushroom seeds for this.
You then have to walk into the chest and move it outside in front of the plots for farming. Right in front of the middle ones is ideal.
Step #2: Jump on Chest and Farm
Now you have placed the chest you can jump on top of it and you will be able to reach every crop JUST. This means you can just use your mouse (if you are using mouse + keyboard) and grow and harvest without moving.