you should invest in buliding a small "veg box and seperate the two, you will need new supplies but it will be worth it in the end. i built a 3' x 8' x 5' tunnel last year ( i will add pics) and it costed me arou $200 - $300 for every thing. half of one of the 8 plants covered the cost. Its deffinatly worth doing it right and reusing the system over and over. for the light you should use tarps or something of the sort to reflect the light to the ground.