No, all cucumbers are not imported. The US grows in season produce. During off season or low crop yields, we get food from Mexico & Canada. Southern states supply northern states but usually only east & west regions. So Florida supplies cucumbers to the east half, California to the west. Other states do grow them like Texas & Arizona. But we get a lot from Mexico, like a shit ton from Mexico, they make a lot of money from that supply line. That's just cucumbers.
It's very similar with other produce. Canada supplies a lot of hot house tomatos of all types and mini sweet peppers.
The interesting thing is, we export a lot of white corn to Mexico and there is no tariff on that export. Dumb donnie is literally punishing Americans while selling our exports for less than what we would pay. This is why we have NAFTA, for fairness and cooperation.
Have you tried carrots? They can grow in negative 8 degrees Celsius (around 19 degrees freedom units)
I think broccoli and Brussels sprouts also do well.
When it comes to cucumbers, however, growing a ton, and pickling them is perfect for using all year round, and pickling is also way easier than I first thought.
I've never tried this but how about one of those small DIY greenhouses? Apparently they're pretty easy to make. I'm not sure how cold it gets at your latitude but with a greenhouse you could manage to lower your zone a level. Maybe enough for those carrots.
Worst case I guess is just grow winter crops during the summer. Half a year of cheaper food is better than nothing.
I like growing vegetables and flowers. It is the only think keeping me sane living in the city.
I know some do not, but the tariffs are happening, so best you can do is adapt, though honestly I would suggest it even if the tariffs were cancelled. It saves money, is good for the environment and your mental health.