Thomas Ford, who was 15 months old, was on a walk with his father and a sister when he picked a blackberry off a bush.
The boy, who had eaten them before, choked and was taken to hospital, where he died three days later.
His mother Serena Ford, from Stalham, Norfolk, said her family had been going through a "living nightmare" since it happened on 27 September.
"It's like you're in a bubble," she told the BBC. "Everyone else is just getting on with their lives, but we're stuck thinking 'are we going to wake up from it?'"
Mrs Ford, who also has two young daughters, said: "Having the girls has been great support and we've been supporting each other, but now I want to make people aware and if something good can come from this then it can only be a good thing."
Updates on this story and more from Norfolk
She said her husband Robert was walking their family dogs with Thomas and five-year-old Olivia when they stopped to pick some blackberries.
The 31-year-old nurse, who first told her story to the Eastern Daily Press, said they would often pick them and that Thomas had eaten them in the past without any problems.
This time, however, he began to choke.
Thomas's father could not see anything in his son's mouth.
When Olivia called her mother, she immediately dashed down the road to join them.
By the time she arrived, though, her son was already unconscious.
They tried CPR until the air ambulance arrived, but staff at Cambridge's Addenbrooke's Hospital were unable to save him.
"I didn't think you could choke on a blackberry, as soft as it is," Mrs Ford said. "But there is a potential risk in everything.
"I don't want people to be paranoid, I want children to be children and explore, but parents need to be more mindful of things they wouldn't necessarily think are harmful."
A mother whose toddler choked to death on a blackberry has warned of the dangers of infants eating whole fruit.