Interesting for sure. I have not done much research on this topic, but I do have questions at this point.
1. First, I seem to think that for those who has tried, many say Wow! should have done this earlier, and many say it makes no difference after trying.
2. Why is that so many plants next to metal structures with massive electromagnetic energy fields are not benefited? like near power transmission towels, microwave transmission antennas, etc.
3. I have many metal construction and electrical installations (solar panel system) in my garden, I have not seem any difference in plant growth, that including a 24 hour LED lighting system and an electric fence system which has a high voltage field.
4. Does using copper for the antenna make a difference? As far as I know, to electrons as long as a material is conductive, they don't care. That includes plants, they are electrically conductive. That's how thunder lightning can blow a tree apart, and that's why for some radios, you get better reception if you touch the antenna.
5. If the plants are electrically conductive, they can form what's known as Faraday cage and cut out a lot of "energy" from reaching that tiny antenna under the leaves.
6. This year, I am shocked by how productive my garden have been. Given the fact that all element for my garden is the same as all previous years, the one thing that's changed big time is the weather. Hot and rained every other day. I would not believe any thing I have done can explain this "miracle" .
When Alternate current (AC) was introduced, Thomas Edison insisted DC current was better, when frequency modulation (FM) was invented, many feel that amplitude modulation (AM) was better. They were all wrong. So I will remain open minded.
dcarch