A seed in darkness should not grow. If the Serene Seasons mod is in use, a seed in Winter, for example, should not grow. Perhaps this is as easy as testing if the seed can actually grow before adding a growth tick.

Should bonemeal work? If I use a watering can from another mod, should this increase the speed at which it grows?

Just a few thoughts 👌

Part of the benefits of a botany pot is that it allows some of these conditions to by bypassed. This is also consistent with reality, as it is winter in northern Canada and I have a few crops such as green onions growing in low light conditions.

I do want to add growth conditions to the crop which will allow things such as light level, biome, dimension, and altitude to be restrictions, however those are planned features and things I don't plan to add into the base/vanilla crops of the mod.

It's also not as simple as just checking if the plant can actually be planted. The mod uses it's JSON defined system which has all of the properties predefined. The benefits of this approach far outweigh the limitations it has. Especially when it comes to performance and giving modpacks the capability to customize the mod.

Bone meal does work. Although this is another condition I would like to add to the mod, and will be implementing for certain vanilla crops such as cactus and chorus fruits. The mod has config support for defining new fertilizers, however watering cans are a unique mechanic that don't fit the category of fertilizers. Like all the other stuff, support is planned.

Thank you for the detailed response. Am definitely looking forward to see what you come up with 👌