Omar's children - pictured here Mariam, five, Acha, three, and Fane, six - sometimes help him to tend to the family's goats, or pitch in at harvest time.
Omar is illiterate, and cannot speak French, the official language of Chad.
"I would like my children to learn to read and write and to learn French as well," he says.
"But there is not enough money to pay for schooling. I think my children will have to follow me and become gardeners."