I don't know what plants to farm for the drops, i already got the wheat thins from baker's wheat, but what are the others and what do they drop? also E cuz achievement.
From the wiki, there are 7 upgrades that can drop from harvesting mature plants. They are:
- Elderwort: 1% chance of Elderwort biscuits - +2% cookie production and grandma production
- Bakeberry: 1.5% chance of Bakeberry cookies - +2% cookie production
- Duketater: 0.5% chance of Duketater cookies - +10% cookie production
- Green rot: 0.5% chance of Green yeast digestives - +1% golden cookie gains, effect duration, and frequency; also +3% random drops
- Baker's wheat: 0.1% chance of Wheat slims - +1% cookie production
- Drowsyfern: 1% chance of Fern tea - +3% cps while the game is closed
- Ichorpuff: 0.5% chance of Ichor syrup - +7% cps while the game is closed, sugar lumps mature 7 minutes sooner
Of these, the most important to get first is probably Green yeast digestives because it increases the chance of all other drops by 3%. You can also use the Mind Over Matter aura to increase the chances of obtaining these random drops by 25% (multiplicatively, not additively).