With the addition of the Farming creation in Skyrim AE the way that potions are used in the game completely changed. No longer did you have a mere handful of plots used to grow ingredients at the houses introduced with Hearthfire, but instead have the ability to mass produce ingredients and as such potions and poisons as well.
Hearthfire allows you to add a garden with 11 plots and a greenhouse with 18 plots for a total of 29 plots. While this isn't too different from the 44 plots in the Farming creation, the difference comes from the fact that your farmhands provide you with an additional ingredient from each plot. In addition to this the Steward at the farm regularly provides you with an income. This is particularly useful in the early game as it quickly allows you to accumilate enough gold for training skills. The farm is also a very easy to acquire and cheap to upgrade building in terms of the material needed to consruct all the upgrades.
Not all ingredients can be planted in the plots of fertile soil at the farm and of the ingredients that can be planted the ingredients harvested varies. The ingredients that can be planted and the barvest quantities remain the same as the plots in gardens and greenhouses added by Hearthfire. The alchemy ingredients are shown below:
I originally went to the Farm from Whiterun and by heading west but with me playing the game on Legendary difficulty I found that the number of encounters could be problematic. An alternative route is to take a carriage from Whiterun to Markarth.
Take the road east to Reachwater Rock, which is a particularly good location for ingredients as it has good number of fungi that are regularly needed in my builds. Pop into the cave if you need some ingredients and then continue eastward. There's usually an encounter of a Wolf or a Skeever at low levels. After this you reach will reach a Shrine of Dibella near a bridge. Head over the bridge and take a left towards Old Hroldan and continue past it on the path. You'll pass an iron ore vein and come to a camp where you usually meet either a Wolf or a Skeever at low player levels. Continue on the path past Soljund's Sinkhole and then once at the top of the hill sneak the rest of the way until you can see the Rorikstead town icon on your compass and then head directly there. Then take the road south east and you will eventually see the farm on your left.
To fully upgrade the farm you need a minimal amount of Hearthfire materials and some Iron Ingots. The list of materials needed are shown below:
The total number of ingots needed to craft the materials and build the upgrades are therefore 9 x Iron Ingots and 1 x Corrundum Ingot. I usually get the 5 x straw from the Riverwood Trader before moving on with the main quest to Whiterun.
I usually use Faendal from Riverwood as he's very easy to get as a follower and he is a bow user which helps if a dragon appears near the farm when doing your ingredient collections. To get him as a follower talk to Sven you is usually in the Tavern and ask You and Fanedal both like the same girl? Then pick either of the next dialog choices. Go to the Riverwood trader and talk to Camilla stating Sven wanted to trick you into believing this letter was from Faendal. Then go talk to Faendal and he will be available as a follower. Take him to the farm and talk to him to make him a steward. I usually part ways with him as a follower at this point and he will stay at the farm.
In terms of the building upgrades you have the option to add a library and display room or a childs bedroom. If you add the childs bedroom then the option to add a library is never available. However if you add the library first then you can change this to a childs bedroom at a later stage.
I recommend adding the library as it allows you to add a shrine with the blessing that you want. This also includes the shines introduced by Dragonborn DLC. Choose carefully as you cannot remove a shrine once selected unless you use console commands. With you regularly returning to the farm, to harvest ingredients and collect the profits, you can easily refresh your blessing.
At the stables outside Markarth their is a character called Banning who will sell you a dog called Vigilance. If you take Vigilance to the farm and into the farmhouse, there is a dialog option to tell them to guard the farm. There's a few wolves that spawn in the area so this can be useful to keep your livestock alive.