Vacuum in the manifold drops as engine demand increases. If you use ported vacuum you always have a vacuum signal. If you want to make adjustments it can be done using the advance pot on the distributor when you use ported vacuum.
The decreasing or waning phases are when the moon shrinks from the full moon down to the new moon (darkness). As the moon wanes during the 3rd and 4th quarters, this is a good time to prune plants, as the water table is diminishing and so less sap will flow out of the cut ends.
National Garden Month on April, 2017: What things should I be doing in the garden this month? April, 2017 is National Garden Month 2017. Step Forward National Garden Month. You may consider putting a 'green' cover crop on the garden for now and turn it in in the spring. This will help your soil and feed future plants. If you cannot wait, this is the time to plant bulbs for spring and summer color.