• Gardening Patch (Cooking) or a Greenhouse (Farming)
  
  
  
  
• Seed of your choice
  
  
  
  
• Potable Water(Cooking) or Ice (Farming)

Place down a Patch. Put a Seed (Green for Roots, Brown for Plants) in it by selecting it then left clicking on the Patch.
Left click bottles of Potable Water onto the Patch to water the plant. You have to do this twice for it to fully grow.
In about a day the plant will grow and you can harvest it for 2 of its fruit (Roots or Plants) and a Seed to replant.
You need to get 2 more Artefacts to research Farming which will make it a lot easier.

When Farming is researched combine a Garden Patch, a Habitat Module and 2 Conduits in a Construction Yard to craft a Greenhouse.
Also in the Construction Yard make a Water Supply. One Water Supply holds 200 units of Water. (Just under 7 Ice) You can then get free water during storms by making Rain Collectors for 3 Metal Plates each. During every storm they produce about 3 Potable Water each, so I recommend making a couple of them as storms are a bit rare.
Plants ready for harvest:

Now, you can just live off of just water, but it is better to use the water to farm Crops.
3.5 Potable Water = 87.5 Hunger restored.
That can also make 2 Plants. 1.5 Plants = Plant Slop which is 80 Hunger restored.
1 Plant = 53.333 Hunger, 2 Plants = 106.666 Hunger
Farming Plants is roughly 20% better than just drinking water!
With Roots: (May be wrong, I think Roots take 100 Water to grow)
1.75 Potable Water = 1 Root
2.75 Potable Water = 1 Root Stew
1 Root Stew = 140 Hunger Restored.
As you can see, roots are a very good food source, not even taking Hearty Meals (240!) into account!