I have been away from crappie fishing for a few years (had a saltwater addiction which has been cured by moving from Coastal NC to Richmond area) but I got back into crappies past November. I don't look at the calendar to find best timing for crappie spawn. Water temperature is more important but water temp is hard to monitor from the windows of my house or windshield of my vehicle. I look at the Spring flowers instead.
In Piedmont NC a low of fishermen looking from Spring spawn crappie look for the Dogwoods to bloom, but that misses a couple prime weeks. I get my gear ready when the green part of daffodils is out and just ready to open the yellow flowers. When the flower open get out on the water. Prime spawn seems to be when the wild purple plum trees bloom. I saw one just today. Fished a Richmond area reservoir yesterday and caught 6 keepers in about 2 hours (trouble with trolling motor, I should have done better) and they were all males in 10FOW or less. The females should be in the same area within a day or two.

I hope this helps.

Anybody have any other ideas on how to "time" the spawn?