Green is the color the farming half of the technology tree runs on, and it is the one people run short of without ever working out where it comes from. There are three sources and only one of them keeps giving.
The short version: studying pays the most and pays once, writing scrolls pays forever, and everything else is small change.
Studying is the biggest source and you only get it once
Two hundred and twenty one things in the game can be studied for green, and between them they hold 
6,470. That is the largest pool of green in the game by a wide margin, and every point of it is one time only.
So the 
Study Table is a budget rather than an engine. Spend it on the things you will not easily get again and leave the ones you can make more of, because a studied item is worth nothing to study twice.
Fish are the best green in the game per item
Twenty two fish can be studied and they carry 915 between them, which works out at forty two green a fish. Nothing else averages close: cooked dishes come to twenty five, seeds and crops to eighteen.
They are also the only large green source you can go and get more of. The better ones pay sixty each, an 
Eel among them, and since fishing spots do not run down you can keep catching study material rather than spending something finite.
A cooked dish is worth studying too, but the fish that went into it was worth more on its own and you cannot study both. Put one of each species through the table first and cook the rest.
Scrolls are the only infinite green, and one is worth four of the others
Five potion scrolls are written at the 
Writing Desk, and all five cost exactly the same: one 
Ink, one 
Clean Paper and one 
Faith, six seconds a scroll. What they pay is not the same at all.
A Healing Potion Scroll returns 10. An Energy Potion Scroll returns 10 and 
5. A Speed Potion Scroll returns 
5 5 10, and a Grow Potion Scroll 5 5 5.
A 
Krotowuha Scroll returns 20 20 20 for the same ink, paper and faith the others take. That is sixty points against the fifteen a Grow Potion Scroll gives you, from an identical shelf of materials and the same six seconds.
It wants Book writing nine, which is the only reason to write anything else, and the moment you reach it there is no argument left.
That makes scroll writing the green engine of a long save. Studying runs out, fish run through the table once each, and the scroll keeps paying as long as you can make paper and ink and hold faith.
You need less than you think
The whole technology tree, all two hundred and thirty six nodes of it, costs 5,129. A hundred and eleven of those nodes want green and the dearest of them is a hundred and seventy five.
Set that against the 6,470 sitting in the study list and the arithmetic comes out kindly: studying alone covers the entire green half of the tree with room to spare. Green is not a material you have to farm, it is one you have to avoid wasting.
Red is the color that bites, which is worth knowing before you spend an evening writing scrolls for green you already had. The scroll is how you get green faster or after the studies are gone, not how you get enough of it.
Everything else is small change
A hundred and eighty eight recipes pay green when you craft them, from one point up to ten, and most sit at the low end. 
Chocolate is the best of the ordinary ones at 10 a batch, which is respectable next to a scroll and comes with fifty energy attached.
Clearing scenery pays too, at one point a bush or tree across about a hundred and sixty objects. That is two hundred and forty five green for the whole map, spent permanently, so it is a by-product of wanting the space rather than a reason to clear anything.
Putting up a building pays a handful as well. Thirteen of the placements give green, most of them five, which is worth knowing only because it arrives free with something you were building anyway.
Graveyard Keeper 2 green points FAQ
How do you get green points in Graveyard Keeper 2?
Three ways. Studying items at the Study Table pays the most and pays once, writing potion scrolls at the Writing Desk pays forever, and crafting or clearing scenery pays a little. Studying holds 6,470 green in total across 221 items.
What is the fastest way to farm green points?
Write Krotowuha Scrolls. One ink, one clean paper and one faith returns 20 red, 20 green and 20 blue every six seconds, and it is repeatable. The other four potion scrolls cost the same and pay between 10 and 20 points in total.
What should I study for green points?
Fish first. Twenty two of them can be studied for 915 green between them, which is 42 a fish against 25 for a cooked dish and 18 for a seed. Fishing also renews, so studying fish spends nothing you cannot replace.
Do green points run out?
The studying does. Every item pays once and there are 6,470 green in the whole pool, so that part of the game has an end. Scroll writing and crafting do not run out.
Why is the Krotowuha Scroll better than the others?
Because all five potion scrolls take the same three materials and the same six seconds, and only the payout differs. Krotowuha returns sixty points across the three colors where a Grow Potion Scroll returns fifteen. It needs Book writing nine.
Does clearing bushes give green points?
One point each, and about 160 objects on the map give it, so 245 green for stripping everything. They never grow back, so treat it as a by-product of wanting the space.
