It might the middle of winter, it might be the middle of summer, any time of year is good for thinking about gardening. Each season of the year comes with something you could be doing in your garden.
Homesteading is a lifestyle of self-sufficiency. It is characterized by sustainable agriculture, home food preservation, and more. Gardening is just one element of homesteading.
You don't have to have a large plot of land for gardening, you can be very successful with container gardening. There are some plants, tomatoes for instance, that do amazing in containers.