If you were to decide to live on a spaceship for the rest of your life, how would you farm?
But what would the most effective way to farm on board this spaceship be?
Farming in space is actually quite similar to farming on Earth, but with only a few differences.
In space, farming is usually done without the typical use of sunlight. I suppose you could use sunlight if you wanted to have a window to the sun in your farming room, but it would be much more likely that you would shine LEDs on the plants to deliver the appropriate amount of light. This constant light would enable plants to grow slightly more quickly than on Earth, where they have ~12 hours of darkness per day.
Plants also have a hard time growing in the correct direction in space because, on Earth, they use gravity to determine which direction is up and which direction is down. If you have a big enough spaceship, you could spin it to generate some gravity (you do not need one full g). Otherwise, you could do what they do on the ISS and place the seeds in "plant pillows" that encourage the plants to grow in the correct direction.
Once you solve those problems, now all you need are the standard things that plants need: soil, water, nutrients, etc.
EDIT: Upon doing some research in response to a comment, I have found that not all plants grow better in constant sunlight. Some plants need periods of darkness each day (the length of which varies from species to species) for optimal growth.
Sources: https://www.nasa.gov/content/veggie-plant-growth-system-activated-on-international-space-station
If you are living permanently on a spaceship, do you have gravity?
There could be spin sections to provide a stable deck. At the large end, perhaps an O'Neill cylinder. Many fictional settings have some sort of artificial gravity. Completely against physics as we know it.
Soil or hydroponics?
It is possible to grow plants without soil, like hydroponics or aeroponics. Using that saves mass, which will be important for space travel.
Any livestock?
A farm could include rabbit hutches, or fish tanks. Or the spacers look for a balanced vegetarian diet.
What about waste?
A closed ecological system could provide air in addition to food, and take care of biological waste.
So the farm on the ship could be much like one on Earth, if you want it that way and if the designers have payload to waste. More likely, it will be an industrial-looking food production facilitiy.
Whether connected as a separate cylinder from the living spaces or as a separate station nearby, you would want to build a place to do the farming. You would not really want to do it in the same place as the humans are living for various reasons.
Plants will not have the same temperature, gravity, atmosphere, and daylight requirements as the people. In particular, if you develop vegetable crops that can grow year round (like cabbages from the arctic circle that are accustomed to 24 hour days in the growing season), you will then want to keep these plants in full sun at optimal temperature (likely around 30 C) permanently. 30 C, and full 24-hour sunlight might not be the best conditions for people.
Since you would presumably develop low-gravity plant variants, your primary concern would be shaping a habitat so that it faced the sun (or got reflected sunlight) 24/7 to maximize growth per space. Space is your primary constraint; fertilizer and water are cheap compared to space stations. It is worth your effort to make optimal growing conditions to get 6 harvests per year to save space.
These conditions would probably not be great for animals, so the spacer would likely be a vegetarian. You would lean hard on beans and other pulses to meet protein requirements. Hope you like tofu!
Building vertically and trying aeroponics would probably not be useful. Since you are making your own station, you can design its geometry. Your geometry should involve the most area with applied sunlight possible, and that area should have gravity applied tangential to it, as on Earth. Plants will need some sort of gravity for their pressure based internal mechanics to work. Then you can grow Earth plants, slightly modified for space on this area. Aeroponics is great in theory, but there does not exist highly productive aeroponic breeds of corn, soybeans, lentils, potatoes, whatever else you want to eat. There do exist highly productive varieties of those plants for use in soil, so you should go with that.
So, in conclusion, develop a specialized farming station to grow your food at optimal conditions. This will give you the most food per area/volume while you are in space.
I would go three ways:
I did not specify the kind of high fat plants because I lack the expertise when it comes to what would work. But there are an abundance of plants that produce oil. Soy, Rapeseed, Helianthus for example.
Here is an called Why Martian Settlers Will Eat Potatoes, Insects, Algae and Mushrooms. It is about food that could feed settlers on mars. They suggest potatoes instead of oil-plants but the rest is more or less what I suggested.
