Test the almanac date, May 1st, against the moon phase date. i.e. plant some of your seeds/plants on May 1st, check them daily and take pictures to document when they germinate or start growing then plant some more of the same kinds of seeds in or near the same space, on the full moon May 21st and again document when/how they germinate or grow.
Try to water/fertilize equally as they grow so they have an equal chance to make it. Be sure to tag or label the two plantings so you can keep track.
Then take pictures of all the plants at weekly intervals through June just to compare growth or success rates.
Then for a fair comparison, you'll have to do this same routine for the next 5 years, too . . (justkidding!)
We want to see the pictures, for sure!
