Planting
-------------------------------------------------------------------------------------------------
Now that you've gotten soil and seeds (hopefully), you'll want to plant them. Simply click on an empty plot, place the desired soil on the left side of the menu that pops up and place the desired seed on the right side.
As a recap of what each of the soils do,
Thanalan Soil: Significantly increases the chances of intercrossing taking place. Grade 3 is reported to have around a 90% success rate.*
La Noscean Soil: Increases the chances of harvesting HQ crops. This does not work for "deluxe" seeds (e.g. Dalamud Popoto, Star Anise, Glazenut, Chocobo Feed, etc.) because HQ versions of these items do not exist.**
Shroud Soil: Increases the chances of higher yield. Shroud soil doubles normal yield, so you will get 24 for normal crops, 10 for deluxe cooking materials (e.g. Dalamud Popoto, Star Anise), and 18 for chocobo feed (e.g. Krakka Root). It also increases seed yield in the off-chance that it successfully intercrosses without Thanalan Soil. However, this does not work for seeds that yield 1, so you will still receive 1 glazenut, 1 jute, etc.
* Not thoroughly tested, just rough estimates based on a limited number of observations.
** You may verify the non-existence of HQ versions of these items in the official item database.
It is important that you plant them in an alternating and circular fashion (example shown in the image below). There is strong evidence that intercrossing is determined upon planting the seed so you do not want to plant a seed next to nothing if you can avoid it.
So for example, let's say you want to cross honey lemon and prickly pineapple. This is the order in which you should plant them:
1 - Honey Lemon
2 - Prickly Pineapple
3 - Honey Lemon
4 - Prickly Pineapple
5 - Honey Lemon
6 - Prickly Pineapple
7 - Honey Lemon
8 - Prickly Pineapple
* An optional technique you can use is to plant the cheaper of the two seeds you want to cross (also with cheap soil), plant your next seed normally, remove the cheap seed, and then finish the rest normally. This makes it possible to have up to 8 seeds per bed but it comes at the sacrifice of one seed + soil.
Fertilising and Tending
Plants can be fertilised once every earth hour using Fishmeal to speed up growth by one hour. You'll want to do this as frequently as humanly possible.
Tending keeps the plants from dying. You can tend as many times as you want at any time without negative consequences, but you'll want to do this at least once every 24 hours.
Harvesting
When plants are ready to be harvested, they will grow to max size and sparkle.
Once plants are fully grown, you will no longer be able to fertilise or tend them. This means that the plants
will die if left unharvested for 24 hours. Harvest them as soon as possible!