I was looking for a nice Minecraft challenge today, and I decided to return and tackle an Ocean Monument that Joop, Phisagram, and I found a few months back. I’d started an approach to the monument via an underground tunnel back then, and and so I had considerable success today avoiding the bulk of the Guardians by continuing the tunnel and then working my way upwards from below.

Ocean Monument Garden, looking toward the monument-arch Greenhouse,” animated GIF by @GumbyBlockhead
Although my traditional approach makes use of gravel for removing the water from the rooms, I was fortunate enough to run into a chamber of sponges early on, and that made things all the easier. Although I had started mining the Sea Lanterns to begin with, once I found the sponges it was a lot easier to move more quickly and leave the lanterns in place and so a good number of them remain where they were originally located.
Once the main cavity was cleared of water and the chamber walls were broken down, I tackled the arch area, thinking that the existing structure would make for a nice greenhouse. The first crop planted was the wheat in the greenhouse under the arch.
The main section of the garden features a large fields of each of watermelons, pumpkins, carrots, potatoes, and beets. To ensure good plant growth, I installed a lot of torches within the monument and also opened up the ceiling to sunlight by enclosing the top portion of the monument in glass. Once the gardens were planted, I took some time to light up the exterior as well with some sea lanterns from a previous monument.
The end result looks beautiful from the nearby tower.
Here is a shot from another angle, showing the Ocean Monument, and the Gumby Tower located on the nearby isle. Joop’s Bountiful Tree is visible beside the tower.
I once spent the better part of a week clearing out an ocean monument with the intent of building a Guardian Grinder. Sadly the project was on a server that is no longer online, and so I only have screen captures of the progression. I’ll have to return and attempt that project on GumbyCraft, knowing that the world won’t be suddenly up and disappearing on me.