Lawn Mower is the fifth item unlocked in the Gardening Supplies store. The Gardening Supplies store is unlocked at Level 14, the fifth commercial building to be unlocked.
Lawn Mowers can be produced in 564 minutes(9 hours, 24 minutes) in 3 stages without using the Global Trade HQ or a Speed-Up Token. Based on this production time, the simoleons/minute is 1.48. (High-tech Factories and 3-star shops were used for these calculations.)