OFFSET: stay in range

Hello,


I need a chart which predicts when a product is ready for harvest.

production date + amount of grow days = Production output date

For this I use the OFFSET function

The issue is, as I have to use a negative number to reference the growth date in the past, I get results out of the range C3:H5.
Screenshot_1.png


How do I limit the OFFSET function to the range C3:H5?


Any help is greatly appreciated.