We grow a seasonal garden, much larger than most people I know, about 3 acres and we don't keep tedious records or really optimize it but it seems like it would fall far short of being enough food to live off of.
The hardest part is growing enough protein, which is why livestock is sort of a necessity for subsistence living unless you live someplace with accessible and abundant fish or game. One past solution was collectively owned and worked acreage devoted to beans, milk or similar, though I suppose it could be argued that leads us back here, eventually, once someone gets the idea to sell the surplus of that. (It did once, already)
TL;DR Check out "Four-season Gardening" by Elliot Coleman for interesting ideas on expanding your growing season without adding electricity
https://www.waldeneffect.org/blog/Calories_per_acre_for_vari...
https://www.quora.com/What-crop-including-tree-crops-produce...
Most peoples' gardens aren't exclusively growing staple crops, so some land would need to be set aside for nutritional completeness. Calories/acre isn't a complete picture; root vegetables require less processing than grains. In a "collapse of supply chains" situation, that needs to be included.
If you're using them to supplement sunlight, the electricity required depends on your local climate, efficiency of your lights, etc. I've found that the most readily available data on that is from marijuana enthusiasts, amusingly.