do i need ventilation

im doing a grow out of a homemade box and i was wondering to save money if i could leave the opening open alittle so that fresh air would enter and hot air would escape enough for it to be the proper temp

What lights do you plan to use? This will greatly impact the heat levels.

Try grab some PC fans. these should be adequate for the time being at least!

GOod luck!

i plan on using cfls

i found one of those duel fans laying around and it has an exhaust setting could i use that

I am speaking from 100% experience when I say that "saving money" on a 1st time grow usually means adding headaches! Walmsrt has a cheapo fan for $6. I did not have a fan on my first grow and had to use pipe cleaners to prop my plants. Now on my 2nd grow my 2 week old plants have stems as thick as pencils!

Kimi

Kimi is wise

I added a big box fan (on low) for my babies and the roots are really liking it. a CFL grow without a fan to strengthen the stem will result in some weak stems.