Steven's Conservatory is a location that first appeared in Steven Universe: The Movie.
This crystal-domed conservatory contains a second, galaxy-capable Warp Pad and Steven's own Diamond control panel similar to the one in Pink Diamond's Moon Base. The conservatory also functions as a sunroom and greenhouse, containing multiple potted rose and hibiscus bushes, gardening tools, a bench, a bean bag chair, and a bed for Lion.
After refusing the Diamonds' offer to stay on Homeworld, Steven warps back to the Conservatory, where Connie is waiting for him. Steven can be seen using the control panel before the two exit the room. Later on, he follows Spinel to the Conservatory only to see her crying over the fact that Steven have abandoned her. After Spinel's memories are recovered, they come back through the Conservatory before going outside to fix everything happened.
Noticing Pink Diamond's Zoo floating outside, Steven goes to the Conservatory where he greets Jay-Ten and Wy-Six through the communication panel. The Conservatory makes another appearance at the end of the episode, when Steven catches up to the Rose Quartzes right before they leave, and meets Amethyst after her trip to the Zoo.
Steven's Conservatory now has become home for many plants, including Cactus Steven, after he leaves Little Homeschool. Cactus Steven spend most of his time growing up here, however, the room is destroyed in an attempt of Cactus Steven to get outside to find Steven.
He walks in it when he exits the bathroom