biology! test for starch

this question is quite interesting.

potatoes store starch as a food storage for undesirable environment (eg, coldness and dryness in winter), while they consume the food storage when they grow into a new plant (eg, in spring time).

therefore, it's reasonable to think that starch content in autumn's potatoes is higher than those in spring.

you haven't mentioned the method employed to test the starch.
i assume you're adding iodine solution to extracts of crushed potatoes in water.
then, one would expect that the blue color for autumn's potatoes would be much deeper than that of spring's.

For the same species of potato, starch content in autumn harvested ones can be considered higher than spring harvested. However for different species, it may be the same cases. Spring harvested species could inherently contain higher starch than the autumn harvested one.