Crystal Growth Accelerators will allow you to grow seeds at a very accelerated rate (this is mod pack dependent). Puting 4 of these around each other with a hole in the middle for water is more than enough:
A 5th one can be added below the water but this is not needed. If you rotate the accelerators on the sides, you can make the wiring a lot neater. These accelerators will need to be powered via ME Glass Cables (smart cables can also be used) and a power source. Once power is connected the accelerators will pulse purple, these accelerators will constantly draw power, these should be turned off when not in use. A simple solution would be using an ME Toggle or inverted toggle bus:
Throwing seeds into the water (that is surrounded by accelerators) and waiting a short while will eventually lead to the crystals being fully grown. You can check these crystals by jumping in the pool.
These crystals will not despawn when fully grown and the accelerator will keep draining power. These crystals are synthetic and can not be ground up and made into more seeds. You will double your crystals by turning them into seeds and growing them, this will help early game.