Fishing seems later then past years

My wife and I made our annual trip to the Williamsburg area from 3-20 - 3-24 from our Pa home. First stop was in Fredericksburg Va fishing the Rappahannock for shad. Nothing and no one else caught one on Sunday. I fished Beaver Dam Swamp reservoir Sunday PM and Monday around lunch in the upper area. No crappie but there were some small bluegills caught. I tried at Rock-A-Hock on the Chick ( off of the floating pier) and caught some ring perch but no crappie. I did not see anyone catching any in boats in my area either. I did talk to one fishermen who caught some a few days prior in the dock pier area down stream. I fished Little creek park also for a hour. Nothing and the lake is draw down about 6 plus feet.
We enjoyed the nice weather and did some sight seeing so it was a nice trip despite the lack of fish caught. The water seemed cold and the foliage seemed to not be in full swing-bloom as in past years so I can understand my lack fish.

YOu may be right. I had a fair day on the last full moon on the NWR, catching a few in the 11-12 inch range, which is big there, but they were all males.

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?

Having real problems finding them in my local lake near Charlottesville. Hammered them when they were deep and stacked up in winter, but they moved once waters started to get up past mid-40's and have not been able to find them for over a month. 5 trips with either a skunk or just 1 or 2. Fished every inch of the lake, as well as a friend in another boat, it's like they are gone. Have been expecting them to show up on staging areas but no pattern yet other than they are no longer deep. Water temps have been slow to rise due to cold nights and limited sun, hope that changes soon.

Good point CproDave. I work as a fly-fishing guide and do seminars and schools on fly fishing and one question I get regularly is do fly hatches correspond to vegetation growth.
I believe that is true but there are exceptions.
A good example on crappie migration would be on Beaver Dam reservoir near Gloucester Va .If we get a warming spell in February the crappie can migrate to the upper end of the lake in the stream area. Then a normal ( cold spell) comes back and they move out. I was there last week and no one caught a crappie in that area. However one fishermen told me they killed them the previous Sunday. A few years ago I did well one day in early March and went back 2 days later. Same results as the weather turned to a sever cold spell and they moved out of the water do to the drop in water temps.
In mayfly hatches I have seen the same thing. One day they are popping everywhere then a weather change and the hatch is hardy noticeable. Also some insects like Bluewing olives prefer overcast drizzly days. On sunny days none can be found but you might see black stone flys early in the year. Mother nature is very interesting to me.