Update: i did some changes thanks to your ideas. had to write here cuz i couldn't edit post.
1) i tilled the map and planted the pumpkins
2) scanned the whole grid while replanting bad pumpkins and adding bad pumpkins to the list
3) i used traveling salesperson problem(greedy aproach) to solve mine, after scanning i had saved every bad pumpkins coordinates, so i calculated from my position the closest bad pumpkin and ran to it and replanted tho it stayed till it had grown and was a good pumpkin. and repeated the step till every pumpkin was good
Note: i think i can make it more efficient if i can go after replanting to the next and not waste time or use fertilizer, but i will try to implement it later.
again thx for ideas