Fred and Lamont are planting a garden for the first time, but they had a garden already two seasons prior when Grady was running the house in Fred's absence and they unknowingly grew marijuana in it.
The finding of oil under the Sanford's property is meaningless as it was very unlikely that they purchased the mineral rights when they purchased their home. Few homes are sold in areas of California where oil or water aquifers are present are sold with the mineral rights to the land.
Additionally, the relatively small plot of land that their junkyard is on would hardly be able to produce enough oil to make drilling profitable for anyone, much less an Arab sheik.
Additionally, the relatively small plot of land that their junkyard is on would hardly be able to produce enough oil to make drilling profitable for anyone, much less an Arab sheik.