I keep hearing about things I want to grow being cold hardy to zone 5, but I live in zone 4, will I still be able to grow those plants?
Sometimes you can. The winter hardiness zones is an approximation and meant to guide you in which plants to select, however it's broad sweeping. Each area will have microoclimates that are +/- 1 or two full zones depending on circumstances.
A south facing slope will be warmer, and so will the ground on the souther face of your house or other building.
Northern facing slopes, the north side of your house as well as dips and valleys in the ground where cold air can flow to and settle will be also be colder.
So if you have a north slope, and or the south face of your house and the ground in front of it is in full sun during the winter months, you may have good luck with plants that are zoned warmer than your zone.
Oftentimes, many trees and shrubs you can select have a colder hardy variety you can select that will produce similar results to its warmer cousin. It may not be exactly the same taste or texture but if that's what you have to work with, then use what you have.