A batch code connects material to its history. The matching tags in the picture represent that link; the colour alone is not a record. Write an actual identifier and keep the underlying dates, supplier details and operations.
Record which spawn lot went into which substrate batch, where the bags or beds were placed, when they were handled, and which harvest and dispatch lots came from them. If several crop batches enter one dispatch, record each contributing batch.
Worked example: two substrate lots share a room, but slow development occurs mainly in one lot. Keeping their identities allows you to compare preparation, inoculation and transport history. Mixing the records removes that opportunity. This example does not establish what caused the problem.