Sea grass is a non-solid plant-based block generated in all types of oceans except frozen ones. They have a two-block tall variant called tall seagrass which is just as common as regular ones. Both tall and regular seagrass have an animation that makes them look like they are moving with the water currents.
Small and tall seagrass blocks (via screenshot)
Seagrass is naturally generated in both tall and small forms in all ocean biomes except the frozen ocean. They are quite common around kelp and other underwater vegetation. It is also generated in rivers as well and can be found growing on gravel blocks. Players can harvest seagrass with the help of shears but use any other tool and the seagrass block will break and drop nothing.
Players can grow seagrass by using bone meal on any non-transparent block that is underwater and there must be at least 2 water blocks above the block you choose to you bone meal on. Another source of seagrass is turtles as when a turtle is killed it can drop between 0 and 2 units of seagrass although this number can be increased with the use of a tool enchanted with Looting.
Seagrass found underwater growing next to some kelp (via screenshot)
Seagrass is a non-solid block that can be used for a variety of things: breeding, composting, and feeding turtles.
Seagrass is most commonly used for breeding turtles and by feeding seagrass to two mature turtles players can breed them. Once a baby turtle has spawned you can feed it seagrass to accelerate its growth and once it becomes an adult it will drop a scute.
Turtles being bred with the use of seagrass (via screenshot)
Seagrass is not the most efficient item to compost with, it only has a 30% chance of increasing the compost level by 1 whenever a unit is placed in the composter.
Seagrass is a non-solid block that is only found underwater in oceans, lakes, and rivers. They do not spawn in frozen variants of the above-mentioned water bodies. They have a variety of uses most common of which is breeding and growing turtles.
A. Seagrass can be grown by players by simply using bone meal on non-transparent blocks underwater.
A. To harvest seagrass you will need a pair of shears, by right-clicking the seagrass you will be able to harvest it.
A. Seagrass can be found in most underwater biomes except the frozen ones.