One grain of wheat produces a plant with — on average — 5 heads. And each head can develop 20 kernels. Consequently, my original 30 wheat grains will give me an initial harvest of 30 X 5 X 20 = 3,000 grain kernels.
When I then go on to plant these new wheat berries, for my second harvest I’ll get 3,000 X 5 X 20 = 300,000 kernels. Which I then plant. After my third harvests the original 30 berries will have turned into 30 million berries! I figure I can restart civilization, in just a couple of years, from the grain I carry around in my vial necklaces.
It’s all gonna work out. No sweat.