The ecomony''s lousy. Costs are up. Incomes are down. Gardening has many benefits. Sense of peace, connection to nature, sense of accomplishment, source of pesticide-free food, something to do on Sunday morning as the neighbors drive to church.... But if we don't watch ourselves, we can buy great plants, hardscaping, watering systems, packaged compost, and wind up with what amounts to $20.00 to…