My oldest daughter has had her own "plot" since she was about 3. I helped her with her planting back then, guiding where she should put the seeds. As she got older she wanted to do the planting by herself. This led to wild seed sowing and quite a lot of wasted space. We would find clumps of carrots and lettuce in one corner and completely bare spots in the other areas. She would be disappointed things weren't growing well, or wondered how they all ended up in a group.
Here she is with her original "whiskey barrel" garden.
Eventually the planter fell apart with old age, and she got to move up to one of the raised beds to use as her own vegetable garden. Every year she gets to choose what she wants to plant there. Her regular choices are sugar snap peas and several varieties of carrots. She likes to experiment with some new vegetables too each year.
The little gardener with her prized carrots a few years ago.
Now that she's 10 and understands instructions as well as being a math whiz, I tried to think of a way for her to use her math and gardening skills together. I thought this year I'd help her with her spacing a bit by measuring one foot by one foot squares. Not quite square foot gardening but more as a spatial guide for her. Hopefully this will also help her to grow more vegetables since she will be using the space more efficiently
She got right to work the other day planting and marking where she wanted her vegetables to grow. I could see her doing rough measurements and hear her doing a little division while figuring out how many seeds would fit in the one foot square spaces.
Another benefit aside from learning about planting, has been that she just loves eating the vegetables she grows. I think she prefers eating peas to candy. Well, that might be pushing it a little, but she really did learn to like new vegetables this way.