According to the website, there should have been a listing of about 150 plants with an indication of what the moisture meter should read. Watering should be done before the plants reach their wilting point and that is easy to see on herbaceous plants because they clearly look wilted, harder to tell on an evergreen. Meter readings in the 3-4 range suggest the wilting point. If you no longer have the sheet, perhaps contacting F-M would get you a copy. Sandy soils will dry out sooner than clayey soils and soils higher in organic matter will hold more water than other soil types.
