Best method - shapes, layers link Excel data

[sos4visio]

We are new to using Visio 2010. We also use Excel 2010. We operate a greenhouse and need to track planting data within the planting beds. The beds get replanted year-around based on the seasonal crop. Each bed is assigned a unique ID and that is the sheet tab name in Excel.

So we have 10 beds per row and 7 rows, so 70 beds within the greenhouse. We know how to link the planting data (bed id, date planted, crop, etc)to a bed (shape) for the first planting. Once that crop is harvested we plant a new crop of something else. So our question is:

Do we create layers within a shape and link new, subsequent planting date to that layer?  Or can we only link data to a shape, and therefore we would have to add a new bed (shape) on top of the original bed and layer that way?

We were hoping we could distinguish the layers (or stacked shapes) by seasonal color that would change automatically based on the planting date field. So if we planted a crop on 4/1/11, that shape would be Green for Spring. After 6/21 it would be Red for Summer, etc....

We do not know how best to develop this process. Please advise. Thank you.