Due to no punctuation (not complaining but explaining) I am not sure where your question starts and ends exactly, but I will answer, somewhat.
Normally when the shards crash that means one of two things, a revert or they do not save after the crash point, this in turn should mean that plants should not grow any more than they had up until the shard crashed until the shard comes back online, once the shard is back online they would continue to grow normally. The plant growth cycle is at server maintenance? If so they would have grown normally at server up, then you tend to them then if the system crashes it will either be saved that you tended to them or it will not save at which point you will have to tend to them again once the server is back up and before the normal maintance time.
Not sure if this helped at all, but I hope it did. o.o