I read somewhere that you can't grow more than 100 lollipops a second. Is this true? If so, how many lollipops do I have to plant in order to get 100 a second?
After you beat the final boss, you unlock the ability to create "bugs" in the game using the Developper's Computer (that is not a typo). However, these bugs cost millions of lollipops to use. This is no issue at this point in the game. One of the so called bugs removes the 100 (300 with horn) cap. So if you invested beyond the 17,401 lollipops into your farm, it'll produce more, up to 10,000 lollipops per second. However, at this point in the game, this is just for laughs as the so called "bugs" can be used to gain 1,000's of trillions of lollipops and candies. (This particular bug costs 10 million lollipops)
If you're looking for the legitimate way to get 100 lp/s you can do that, but it will take some time;
One you've managed to plant around 17,000 Lollipops in your farm, you'll achieve 100 Lp/s.
You can increase your maximum Lp/s by getting the Horn O' Plenty by killing the Cow King on the Cow level. But that's a looooong way away.
Once you've unlocked the Developpers Computer, you can "hack" more unlocks getting up to 10,000 Lp/s. With 30,000 Lp/s via the Horn o' Plenty.
Open the Developer Tools (Right click, select Inspect Element) Go to Console. Type in the following.
X being the amount you want, and you'll see it will instantly change your set amount of lollipops to X
If you're looking to set your candies per second, that's easy too;
Hopefully this helps!