Pregnancy and postpartum maternal nutrition is a major driver influencing maternal and child health. In rural Ghana, teenage mothers are confronted with distinct nutritional challenges that stem from poverty, lack of autonomy, and poor food handling and storage facilities. Post-harvest consumption behaviors of fruits and vegetables among teenage mothers in Mamprugu-Moaduri, West Mamprusi, and East Mamprusi districts and their impact on mothers’ nutrition were investigated in this study. A prospective longitudinal mixed-methods design was used with quantitative surveys, as well as qualitative interviews and focus group discussions. Three hundred teenage mothers aged 13–19 years were chosen for the study based on multi-stage sampling. Results showed high dependence on locally obtained fresh fruit and vegetables during peak seasons with modest storage capacities. Wild sources, including shea fruit and baobab leaves, supplemented diets but were consumed on a seasonal basis. Also, handling practices for fruits were dominated by immediate consumption, and 66.5% and 74.2% of fruits and vegetables were consumed within the same day, respectively. Better storage protocols (e.g., drying or refrigeration) were less common (<9%), but were associated with higher dietary diversity scores (p < 0.05). Improved storage practices were positively associated with education level (χ² = 12.4, p < 0.01). Qualitative studies revealed economic constraints, cultural beliefs, and infrastructural hurdles as hindrances to fruit and vegetable consumption. This study fills in the gaps in the literature by focusing on teenage mothers, a group that is rarely examined in maternal nutrition literature. In deprived rural settings, findings highlight the necessity of context-appropriate interventions, such as increased storage technologies, nutritional education, and livelihood support to improve dietary diversity and maternal health outcomes in these rural districts.