Saturday, July 27th was a great day at the Sunflower+ Project StL site – not only for the great weather, but for the results that we were able to observe. The results were a bit unexpected, but as you will see below, a positive sign that electro-horticulture works in a field environment.
Upon arrival we immediately noticed that there was a single row of sunflowers that stood head and shoulders above all of the other sunflowers in the field. By this I mean that they were almost a solid foot above the rest. But things weren’t exactly as they seemed… I forgot that there were multiple types of plantings that took place in the spring.
Planting Dates Review
The first planting took place on April 27th at Kraut Farms <link> in the greenhouse. Seedlings were planted there because we didn’t know if the ground was too toxic to plant on or not and we wanted to get the seeds going in.a more safe soil environment. The 2nd reason was weather as we wanted to avoid any late frosts that would thwart everything.
So on May 18th, the day of the award ceremony, we planted everything: first the seedlings, then a couple of rows of directly-sowed seeds. A row was done just outside of the electrification area with 1-2 seeds in each hole and another row was done about 15 feet away or so with clusters of 5-10 seeds in each hole.
When we arrived, a saw the following:
The first thing that I noticed was that we had a row of sunflowers that stood on average about a foot taller than the rest of them. The second thing I noticed was that the rest of the field had gone to seed and the flowers were all wilted. Here’s another view:
The tallest row is different not only for its height, but also its age, it’s worth noting that aside from being younger, the plants are from the same batch of seeds and are effectively the same. By this logic, the fact that the younger plants are taller than the older plants is significant, as one would expect the opposite to be true.
In the other row of flowering sunflowers, the one about 15 feet away, is also doing well. These are predictably the same height as their older siblings, but thinner and with smaller flowers (because there are multiple plants competing for the same resources).
Later on I noticed something strange… that the plants that were situated between the electrodes were reduced in height based on the distance from the positive electrodes. I expected that the entire region would be at the same height – did I use too low of a voltage such that by the time the field reached the other plants that the field was too low to have an effect?
On the other hand, we had a row that was clearly much taller then the rest. Take a look at the following diagram to get a better feel of what the effects were:
Since a gradient can be seen from taller to shorter across the electrified regions, the fact that the directly-sowed row was 2 rows away means that it received a dose less than the max field strength. Furthermore, the tall plants are from a different planting group, younger ones that were sowed from seed about 3 weeks later than most of the rest of the plot. Based on this observation, I believe this means that they probably did not grow to their maximum height. At the same time I think the greatest growth must have occurred at the time of germination since it is the main difference between the same electric field being incident on both sets of plants.
So here’s a summary of the observed effects (at least for this type of sunflower):
Electrified seedlings aren’t affected as much as electrified seeds
Electrified seedlings experience growth in proportion to electric field strength
For 1.5-3V, the field strength diminishes quickly over a short distance (none of the clustered sunflowers seem to be taller than normal)
Plants outside of the electrified area can also be affected
Now even though the transplanted seedlings weren’t affected by larger growth, maybe they were affected in other ways that we couldn’t observe, e.g. being better in staving off certain diseases or something along those lines?? For a full set of physiological responses, more testing would be needed.
Aside from growth, other physiological observations were the same between both sets of plants: 1) the leaves seemed to be at the same level of greenness & 2) all leaves had speckles over most of them, telling me that electrification did not improve insect resistance in this case.
It’s not over yet, we ran into Richard Reilly and in addition to telling us some interesting revelations that he heard from the horticulturalist, he said that we were likely to continue to let things grow till September. So for the next month or so, maybe we’ll see more growth and/or other effects.