Turnip

Unlocks once you've harvested 150 Carrot, 110 Corn, 70 Onion and 50 Potato in all; unlocking it is then free.

A seed costs 9 spare parts and grows for 5m 24s (4m 19s on fertilized soil), needing water 4 times on the way: it stops growing until it's watered. It gives 8 harvests, growing back from scratch after each one.

Each harvest is one Turnip and 7 spare parts: 56 from one seed, 47 more than it cost, over 43m 12s of growing. In a Biofuel Converter each one is worth 6 biofuel.

A Reaper chip can improve its grow time, watering, harvests, biofuel or earnings.