Step 1: harvest until you get a weed or vermin (on the ground, not on crops)
Step 2: without leaving the farm, queue for a pet pvp battle. Upon finishing the battle you should see another vine spawn on the same spot (harder to notice with vermin, just dig one up and see if there are more under it)
Repeat step 2 as many times as you want (repeated it 4 times myself= had 5 vines on 1 bit of soil)
Step 3: get rid of the vermin/vines in the bugged patch of soil
Step 4: harvest remaining crops, they now should yield 1 crop extra for every time you repeated step 2 (as in you can harvest them 1 time extra for every step 2) the bonus crops (beyond the 1st) end up standing on random ground conditions.
Harvested 5 full stacks of herbs, including 1 golden lotus stack this way today.
Enjoy your harvest