name - The registry name of the item or block you wish to use as a medium. This can be from Minecraft itself (minecraft:glowstone) or other mods (galacticraft:meteoric_iron_ore)
growthModifier- Every 10 ticks or so, the grow bed will roll a random number between 0 and 100. If this number is below the growthModifier value, the plant is forced to perform an extra tick (not a guaranteed growth, just an extra chance at growth).
waterUsage - How much water this medium consumes from the grow bed every ~10 ticks
boostModifier - If you have specific plants set in the plants array, this modifier will be added to the growthModifier when rolling. E.g. You have added terracotta as a medium and put carrots in the plants array. If your growthModifier is 10 and your boostModifier is 6, the chance of a successful roll is roughly 16% when growing carrots on a bed with terracotta as its growth medium.
plants - A comma-seperated list of plants which the above boostModifier applies to. Only plants in this list will receive the benefits of the boostModifier.
Custom Bulbs
color - The color of the bulb. Can be set to 0 (white), 1 (red), 2 (green), 3 (blue) and 4 (purple).
All other fields are the same as the custom growth media above, except the waterUsage is replaced with energyUsage.
Custom Fluids
name - The name of the fluid. For example "nitrogen", "hydrogen".