The number of events is overwhelming, so it is not possible to get everything into What Grows On in RI with the resources I have. Here are major aggregating sites annotated for your information.
Earth Day Event Listings 2003
RI Cemetery Weeks (April-May) - This listing has more than 100 events all over the state, mainly walks and cleanups. Rhode Island cemeteries are very interesting historically. Because RI was not founded as a religious colony, burials were not necessarily in church yards, so there are thousands of burial places.
https://preservation.ri.gov/ricw
RI Statewide Cleanups - Keep Blackstone Valley Beautiful
https://www.keepblackstonevalleybeautiful.com/site/rhode-island-statewid...
This doesn't have as much as I'd expect, but there is a walk scheduled to pick up litter in Central Falls on the 20th
Cleanups April 15 or 16 in Pawtucket, North Providence, Woonsocket, Narragansett, East Providence, and Westerly - see https://litterfree.ri.gov/events
Ri DEM Earth Month Events page (there are 5 pages with events going beyond April through Nov 28
Eastern RI Conservation District (Aquidneck Island (Portsmouth, Middletown, Newport), Bristol, Barrington, Tiverton
https://www.easternriconservation.org/earthmonth
Litter-Free Rhody
Cleanups listing - 3 pages
https://litterfree.ri.gov/events
Clean Ocean Access Signup page (Aquidneck Island)
https://www.cleanoceanaccess.org/upcoming-events/
Cozy Rhody Litter Cleanups (Olneyville - Providence)
https://www.meetup.com/Cozy-Rhody-Litter-Cleanup/
Save the Bay Shoreline Cleanups
https://volunteer.savebay.org/shoreline-cleanups/
Woonasquatucket River Watershed Council Earth Month and Clean Days
(Providence, Johnston, North Providence, Smithfield)
https://wrwc.org/events/
List of RI Cleanup Groups - This list has some of the "usual suspects" but it also has smaller groups that don't get a lot of publicity - East Providence, West Greenwich, Lincoln, Westerly, Richmond,South Kingstown, Middletown
https://litterfree.ri.gov/green-links-resources/clean-groups-rhode-island
EventBrite List of RI Earth Day events (some are irrelevant)
https://www.eventbrite.com/d/ri--providence/earth-day/
RIRRC - Shredding, E-waste, Eco-Depots, Dehumidifier takeback
https://www.rirrc.org/announcements/events
Providence Earth Day (actually April-May calendar)
https://www.providenceri.gov/earthday/
Not sure if all of these are open to public: Salve Regina Earth Month events
https://today.salve.edu/celebrate-salve-reginas-earth-month-with-variety...
