Good choice using the parsley as a choice for the experiment. They tend to rebound well after the stress of transplanting. Even when stepped on, parsley usually keeps growing. Tomatoes and peas I think would work well in an experiment too.
In bonsai, I know some people grow tree stems through a buried washer (similar to your magnet shapes with small hole). Over time it constricts the taproot off slowly, and forces new roots to from a radial pattern from above. This makes the trunk fatter and arguably a healthier tree.
My gut instinct tells me the more magnets on the soil surface, the more you are also forming a mulch layer protecting the soil from heat/cold, moisture loss, and especially damage from burrowing bugs that only lay eggs under damp, organic surfaces. Slugs probably don't like crawling on the magnets with its sharp corners. Perhaps the magnetic waves deter bugs in the same way charged copper wires do.
I would love to see you grow some plants over areas you dowsed as possibly harmful, and compare with areas with good energy. Tree seedlings, if you have any already growing nearby, would be easy to monitor for evidence of long term increasing differences.
Yes, basil was too slow and tomatoes would be better at this time of year. Getting a bit hot already for the peas.
Amazing! Will look in to this.
Could be related to a certain extent. Though this does not explain how the large magnet was able to hold M1 upright on that first day when all the others went droopy.
This is becoming more and more evident over time when I plant rows. Always in the same areas the plants don't do well. Will see if I can get pics to demonstrate this.
I have seven small apricot plants from a local tree which were planted last year, currently around 10cms. These could work...