Squashes and pumpkins are a favoured vegetables among the karanga people. Such is the love for pumpkins in Zimbabwe that one of the best known folk songs celebrates this love in “huya uone kutapira kwaite manhanga” (come taste the sweetness of pumpkins). But for all their sweetness, pumpkins only ripen in the field. In the pot is where they are converted to a delicious edible form whereas in the field they would rot if they are not removed. Hence our elders used this metaphor in commenting about talents or fortune that goes to people who are unable to use them.
The proverb is used a comment indirectly on the failure of someone to make use of the gifts, talents or fortunes they have at their disposal. It’s use can also be stretched to challenge or encourage others to assist the one who cannot use his talents (similarly to going to the field to bring the pumpkin to the pot).