To me, it would depend on how long the lease is for.  A few years, i would try to do it with the full time job.  If it were to keep me locked in for 5 or more, I would probably let the full time job go.  Saying this, in 5 years you may have enough that you can expand your own operation with other leases, or maybe a deal to purchase some more ground.  A lot can change in 5 years time.  Also, could you make it through a break even year on your wife's income?  In my shoes with my full time job is working for my dad and I also have my own ground, I would jump right on it.  But your situation is maybe different.