You have probably already considered the vegetables needed for your family and how growing plants in a greenhouse and help you meet your goal.
But, have you considered how to heat your greenhouse? The heating cost can be very expensive and could take you a few years to regain that expense. However, if you provide your own heat source with wood, windpower or solar you will be in control of your expenses up front.
I, fortunatly, live in an area with lots of woods and I cut my own wood for heating my greenhouse. I have installed a wood stove centrally located and it radiates the heat throughtout my greenhouse.
Now, I do understand that you don't here a lot about heating a greenhouse with wood. And it does create an arid environment that must be supplemented with moisture. I always keep a large pan of water on top of my wood stove with gives me that little extra moisture.
And, I only have to build a fire during the nights and cloudy days when the temperature will drop below 60 degrees Farhenheit.
I only grow cool season crops in the winter months. Cool season crops include: beets, beans, broccoli, brussels sprouts, cabbage cauliflower, collards, kale, kohlrabi, lettuce, parsley, parsnips, peas, radishes, mustard, spinach, and turnips.
You will have to decide which of these plants you will be growing in a greenhouse.
The length of time of growing plants, depends on if you live in the North or deep South. It could be as little as 60 days to as long as 100 days.
It is also a good idea to stagger your sowing of seeds to ensure a constant supply of vegetables. Most people stagger their plants every 10 to 14 days. But you must realize that as temperature change from warmer to cooler the moisture also changes and the growth rates of your vegetables change.
It is always best to be a prepared as much as possible, and there is a steep learning curve when it comes to your greenhouse. But, you won't exceed if you don't try. Get out ther and get started and plant those seeds and care for them.
It does take careful obervation, but you can do it!