Kindergartens are facilities that serve to create Gems by using machines called Injectors. On Earth, there are two Kindergarten facilities: the Prime Kindergarten in Facet Five and the Beta Kindergarten in Facet Nine. The Prime Kindergarten first appears in "On the Run" while the Beta Kindergarten first appears in "Beta", with the Homeworld Kindergarten being introduced in "Off Colors".
The Prime Kindergarten is a vast, foggy canyon with numerous holes carved out of the dark, dull purple rock faces; which are the "birthplaces" of many Gems. Injectors dot the landscape, some of which have fallen to the ground and been destroyed. The site has a single Warp Pad, which is decoratively surrounded by Gems similar to those on the Injectors. This was the first Kindergarten to be developed on Earth and has significantly better conditions than the Beta Kindergarten.
The Beta Kindergarten is first mentioned in the episode "It Could've Been Great". This is the second of the two Kindergartens built successfully on Earth (89 were planned at the beginning). The Beta Kindergarten is in a desert area where Gems emerged from red sandstone.
A Kindergarten is shown on the Gem Homeworld in the episodes "Off Colors" and "Lars' Head". This Kindergarten is the largest one seen so far, appearing to be orders of magnitude larger than other Kindergartens. It is similar in style and atmosphere to the Prime Kindergarten - both are surrounded by fog and contain many holes drilled into their walls. Unlike the Kindergartens on earth however, this one appears to have had every available space used in the creation of more Gems. Some of the spaces between the various holes have broken apart with age. The infrastructure of this Kindergarten suggests it ventures into Homeworld's hollowed-out interior. The Off Colors resided in this Kindergarten, using it as their place of hiding until being compromised.
The Prime Kindergarten appears to be the main reason why Gems invaded and colonized the Earth; to exploit its resources and produce more warriors via the Kindergarten. According to Peridot, the Prime Kindergarten produced Gems mainly of the Quartz variety (which can be seen here). It was once a flourishing center where Gems were grown and manufactured. If allowed to continue, it would destroy all life on Earth as the developing Gemstones would incubate in the Earth's crust and sap the life force from its surroundings to form itself. Rose Quartz saw the error in this, founding a faction of rebel Gems and leading an uprising that caused Homeworld to cease the production in the Kindergarten, driving them off the planet at the cost of being forever stranded on Earth.
Currently, the Prime Kindergarten exists as a ruined canyon. There is a single Warp Pad, which can lead to any Warp Pad on Earth. The Injectors are out of use, although it should be noted that if the Kindergarten were reactivated, then these could be turned on for the continuation of their previous project. However, Homeworld has different plans for the Kindergarten ever since their last project was scrapped due to the war with the Crystal Gems. Their uses for the Kindergarten mainly involve their experiments for a Gem geo-weapon as they use the location as incubation site for "The Cluster" and all its prototypes.
Some of the surviving Quartzes produced in the Prime Kindergarten were stationed at Pink Diamond's Zoo, with the jobs of guarding and maintaining the facility under the command of Holly Blue Agate and Blue Diamond. Each of these Quartzes share the same cheerful, jokester, and casual personality that Amethyst has, which might be because they all came from the same planet.
The smaller and less developed Kindergarten created on Earth, the Beta Kindergarten was created in Facet 9 halfway through the Rebellion to get more Quartz soldiers on the ground in order to compete with Rose Quartz's army, who could heal her soldiers. The Beta Kindergarten was rushed by Homeworld Gems, and because of that the facility was created under poor conditions, and led to quite a few of the Gems produced there being defective. Some examples of this are a Jasper who popped out skinny and a Carnelian who popped out short (like Amethyst).
Like the Quartzes of the Prime Kindergarten, some of the surviving Quartzes produced in the Beta Kindergarten were stationed at Pink Diamond's Zoo, with the jobs of guarding and maintaining the facility under the command of Holly Blue Agate and Blue Diamond. Even the defective Quartzes from the Beta Kindergarten were brought to the zoo rather than be shattered, as Blue Diamond wanted to keep them as reminders of Pink DIamond. These Quartzes also share the same cheerful, jokester, and casual personality that their Prime sisters have.
The Homeworld Kindergarten appears to be the main reason why the Gem Homeworld looks barren and devoid of life; by constanly exploiting their own resources to produce more Gems via the Kindergarten. According to Peridot, the constant use of the Kindergarten on Homeworld caused the planet to lose most of its resources, which led to the creation of Era 2 Gems (Gems that used less resources to produce and have less powers). It's shown in "Off Colors" to be massive, to the point of needing a cave system in order to navigate it. The Off Colors (group) used the tunnels as means to escape and hide from the Shattering Robonoids their entire lives, due of their defects and being force to isolate themselves as a means of protection. Fluorite mentions that the Off Colors have been hiding in the tunnels for eons, indicating that this Kindergarten has been out of use for a long time.
Amethyst introduces Steven to this location. She reveals that she was made there and that Gems used the place to create other "bad" Gems, or "parasites".
The Crystal Gems follow one of Peridot's Plug Robonoids to the Prime Kindergarten. They later cut Peridot's connection to the control room, at the cost of her discovering their existence of on Earth. Pearl mentions the Kindergarten has been inactive for 6,000 years and would destroy all life on Earth if reactivated.
The Crystal Gems go to the Prime Kindergarten to search for Peridot. They find her, but she quickly escapes. Upon further investigation, Garnet discovers that Peridot was not trying to reactivate it, but instead, she is checking on Cluster Gems, former Crystal Gems that Homeworld Gems shattered and forced to fuse, possibly as punishment for the Rebellion.
Peridot takes Steven to the Prime Kindergarten to give him more information about the Cluster, as well as referring to it as the "Prime" Kindergarten for the first time. She assumes, since he is a Quartz, that he was made there as well, only to learn about his hybrid status instead.
Peridot, Amethyst, and Steven retrieve a drill head from one of the Injectors in the Prime Kindergarten to use for their drill, which will allow them to reach the Cluster. Peridot also tells Amethyst about the many Quartzes made in this Kindergarten, and classifies her as a defective quartz.
Peridot shows Amethyst and Steven the Beta Kindergarten to cheer up Amethyst since the Beta Kindergarten is poorly made and thought out. They soon get to Jasper's Hole there, and it is revealed that Jasper was the only successful quartz made there. They soon encounter some corrupted Gems in cages and find Jasper holding them captive.
The majority of this episode takes place in the Beta Kindergarten. During a fight with Jasper, Amethyst and Steven fuse to form Smoky Quartz. While some corrupted Gems escape from their cages, Jasper fuses with one of the corrupted Gems, but they are defeated easily by Smoky Quartz. Jasper and the corrupted gem unfuse, and Jasper herself becomes corrupted as the result of her fusion. She is poofed by Peridot, and the group leaves the Kindergarten, returning to the barn.
The Crystal Gems look around the Beta Kindergarten to poof and bubble any leftover Corrupted Gems that were locked up by Jasper.After the trio fail to capture the Tongue Monster, Peridot laughs at how terrible they were at how they got outsmarted by a thing with bestial instincts. They eventually decide to let Peridot capture the gem herself, but she soon discovers that it is a lot harder than it looks. Many of her "Peri-plans" fail, and she gets frustrated. With the help of Steven, she eventually chases the gem off a cliff, and successfully poofs and bubbles the corrupted gem.
Buddy Buddwick begins to explore the marked areas Pearl had marked for him to stay away from, starting at the Sky Spire, the Lunar Sea Spire, the Communication Hub, and then the Prime Kindergarten. He draws down the holes made from formed Gems, and names the place, "The Many Hole'd Place" in his journal. Buddy feels a bit "off" about his journey until Amethyst comes onto the scene behind Buddwick. He shows Amethyst his accomplishments on the map, journeying to places unseen. However, from the looks of the Kindergarten, many people have been here, and since Amethyst's compatriots drew his map, he comes to realize he is merely a tourist rather than an explorer and adventurer and weeps over it. Amethyst suggests discovering the "Sand Castle" located in the arid environment known as The Desert. This brings back Buddwick's enthusiasm and begins his travel to the Sand Castle.
Holly Blue Agate tells Sapphire and the Gems to excuse the Amethyst guards at Pink Diamond's Zoo because they were made on Earth.
Amethyst reveals that each of the Quartzes stationed at Pink Diamond's Zoo were either made from the Prime or Beta Kindergarten on Earth.
After falling to the underground surface of Homeworld in the previous episode, Steven and Lars were lead into the Homeworld Kindergarten by the Rutile Twins, and met and learned about the Off Colors. When Shattering Robonoids infiltrate the tunnels, Steven and Lars help the Off Colors remain undetected by destroying the machines, which ultimately causes Lars' death.
Continuing off from "Off Colors", Steven resurrects Lars inside of the Homeworld Kindergarten and travels to Earth through his pocket dimension. Returning to the Homeworld Kindergarten, Lars discovers that he can't go through his own hair to get back to Earth, so the Off Colors decide to stay with him to find another way there, while Steven returns to Earth to retrieve help.
- "Kindergarten" means "children's garden" in German and it usually refers to a place of preschool education. In this case, it literally means a garden where children are grown.
- In "Know Your Fusion", Sardonyx makes a reference to the former, joking that "[Jasper] should've gone back to preschool!"
- The area was stricken barren of life by the incubated Gems around 6,000 years ago, as stated by Pearl in "Marble Madness".
- In "How Are Gems Made?", it is seen that Gems suck the life out of their surroundings, and so mass-production of Gems in the Kindergarten left the location in a lifeless state.
- It is unknown how many Gems were grown in the Kindergarten, and where most of them currently are.
- Amethyst was grown at the Prime Kindergarten but joined the Crystal Gems sometime after the Rebellion.
- Peridot has implied that the shards of Gems grown at the Kindergarten and shattered during the war were used in the making of the Cluster.
- In "Beta" it is revealed that Jasper was made in the Beta Kindergarten and her hole was the largest making her "the ultimate Quartz".
- A total of 28 Quartz soldiers made on Earth are shown to work at Pink Diamond's Zoo.
- The person-shaped holes on the sides of the Kindergarten, as well as the manner in which Amethyst slid into hers, appear to be inspired by the Junji Ito horror manga, The Enigma of Amigara Fault.
- Amethyst's hole is one of the few holes at ground level.
- This is because she emerged 500 years later than all the other Gems grown there.
- The Injectors resemble bacteriophages. This alludes to the fact that when a bacteriophage or just any virus invades another cell, the cell will just create more viruses until it is destroyed, much like how when a gem is inserted into the ground by the injector, the ground will become barren and lifeless.
- The body of the rig encases a structure that resembles an organic heart, which is attached to the head and feet via red and blue tubes resembling arteries and veins respectively.
- The Prime Kindergarten created Gems of the Quartz variety, as revealed in "Guide to the Crystal Gems" and indirectly mentioned in "When it Rains".
- Amethyst is a type of Quartz, and she was intended to be a (much larger) Gem warrior.
- Peridot assumed that Steven was created in the Kindergarten because his gem is a type of quartz.
- As revealed by Peridot in "Too Far", Gems that stay in the ground for too long have stunted height when fully grown. An example of this would be Amethyst.
- Peridot also reveals in this episode that the Injectors in the Prime Kindergarten have Era 1 drills, implying that there are more advanced versions of Injectors/Kindergartens.
- In "Beta", Peridot revealed some details that make a quality kindergarten/gem hole.
- The surfaces must be flat (curved surfaces result in Gems emerging sideways).
- The holes must have even spacing and consistent depth.
- The gem should leave a strong clean silhouette and not come out of the hole at an angle.
- Good quality holes have frictional rock melt. (Jasper's exit hole has frictional rock melt, therefore, turning red sandstone into glass.)
- The Beta Kindergarten seems to be located in the Grand Canyon.