If you look a the USA, not as a single country but as 48 countries on the same island, you'd see the same thing.
No state is able to produce 100% of its local food needs. There is a massive amount of import/export going on. So many different climates are in the USA that a particular type of food can be produce year round BUT it will be produced in different areas of the USA depending on the season.
Cuba's pretty much stuck with one major climate and less seasonal changes in the weather than the USA. So instead of being able to grow ... (im just making stuff up as an example)... spinach on the west side of the island for the first 6 months with production shifting to the east side of the island for the next 6 months as the seasons change and spinach gets to be a product that would be in constant production AND available for more of the year. But with less seasonal change/variation in Cuba, their hypothetical spinach farmers might only have one, 6 month period every year to produce all the spinach they could plant, harvest, and deliver to customers.
After that, the farmers have to wait until next year (the next spinach growing season) to try to make more spinach. And until then, there will be a shortage of spinach as the crops from the only period where Cuban spinach farmers could do their thing are exhausted due to spoilage and consumption.
If you look a the USA, not as a single country but as 48 countries on the same island, you'd see the same thing.
No state is able to produce 100% of its local food needs. There is a massive amount of import/export going on. So many different climates are in the USA that a particular type of food can be produce year round BUT it will be produced in different areas of the USA depending on the season.
Cuba's pretty much stuck with one major climate and less seasonal changes in the weather than the USA. So instead of being able to grow ... (im just making stuff up as an example)... spinach on the west side of the island for the first 6 months with production shifting to the east side of the island for the next 6 months as the seasons change and spinach gets to be a product that would be in constant production AND available for more of the year. But with less seasonal change/variation in Cuba, their hypothetical spinach farmers might only have one, 6 month period every year to produce all the spinach they could plant, harvest, and deliver to customers.
After that, the farmers have to wait until next year (the next spinach growing season) to try to make more spinach. And until then, there will be a shortage of spinach as the crops from the only period where Cuban spinach farmers could do their thing are exhausted due to spoilage and consumption.