Get Bright Orange Pampass Grass, Bulrush, or Poppie Seeds.
Have a Water trough from a player vendor and a water pitcher from a NPC Tavern worker. 40 water doses from a regular pitcher. Refill from the trough.
Have kegs of Greater Poison and a source to get or make more. You
will go through a lot. Also have Greater Cure in quantity, and a keg of Greater Heal and Greater Strength. Having an Alchemist would be a good thing.
Get Plant pots from a Provisioner NPC. You can fill them with dirt from a road or other dirt source by double-clicking the pot, then the source.
For growing at your house:
Arrange and lock down the dirt filled plant pots. The dirt in them will be hard.
Double-clicking on a pot will bring up a plant tending window. There will be a red hypen by the water pitcher icon in the upper right corner. With the filled water pitcher in your backpack, click the pitcher icon once to add a dose of water changing the red hypen to a yellow hypen. Click the pitcher icon again to apply a second water dose and the hypen will vanish. The mouse cursor over the pot will now show it holding soft dirt, ready to plant a seed in. Double-click your stack of seeds and then the pot to plant a seed in it. It will show a zero in the upper left corner of the plant tending window.
The next day, after the maintenence period, the plant tending window will show a 1 in the upper left corner and the plant will not need tending.
The following day, and through the next 15 days, you will have to tend the plant with water, Poison, and Cure potions.
You have to do this every day or the plants will get sick. A yellow hypen by the water pitcher icon means it requires one water dose, a red hypen means two doses. If the icon on the left side of the tending window across from the poison bottle icon shows a yellow plus sign, add one poison by clicking on the poison bottle icon. If the plus sign is red, apply two poison. If the icon across from the cure potion bottle icon shows a plus sign, it works the same way applying cure potions.
Overdosing a plant with water or potions will make it sick.
A plants health is shown at the bottom of the tending window. Vibrant & Healthy are good. Wilted ot Dying is bad. If the plant shows wilted or dying, or if you have overdosed it , add health and strength potions by clicking the appropiate icon on the right side of the tending window.
At stage 7 (shown in the upper left corner of the tending window) you should see a plant in the pot. The number stops going up at stage 9 and clicking the flower in the upper left corner should show you a window with two 0/8's beside the center and right side middle icons. The center is number of resources the plant has grown, the right one is the number of seeds it has grown. When the numbers are at 7/8 you can skip tending the plant and harvest the following day at 8/8. With a plant that is healthy all through the process, it is 17 days between planting and a full harvest.
The biggest pain to plant growing is working up the reagent vendors to carrying 999 of each needed reagent and buying them all. I consider it the trial-by-fire of plant growing.
There is a backpack method for growing plants that has the benefit of your plants not getting sick if you can't play one day. The plants only do a growth check when the character logs in, and only does a growth step if it's been more than 23 hours since the last growth step. Tending is the same other than it's more hassle in a cluttered pack of plants. If you use the CC and have UOA, the 'Use Once Agent' is a sanity saver when backpack plant growing.
If your on Chessie I'll provide you with seeds, starting kegs of potions, the water trough, and one of the neat new endless decanters for watering plants.