Yes you need perlite,adding perlite does quite a few things that benifit weed plants.
Increased drainage.
Soil that gets too compact can kill the plant if you overwater,no oxygen is allowed into the inner root mass because the soil never truly dries up,adding a good quantity of perlite helps assure all soil recieves fresh oxygen every watering & dries between waterings.
Loose/fluffy soil.
Adding perlite helps make the soil mixture at it's best potential for maximum root development,root's grow much faster in soil that is loose & fluffy over compact soil.
Added oxygen.
Adding perlite in substantial amounts allows the soil to dry out much faster as saids above,the biggest benifit of quick drying soil is the need for more frequent waterings,every time you water the water delievers fresh oxygen to the root mass which makes the entire plant grow much faster,one of the largest factors why growing hydro is so much faster over soil is the severely increased oxygen delievery to the root mass,flkuffy soil helps close that gap.
Most off the shelf potting soil is pure shit as far as nutrients within the soil & should be amended before planting,here is the mix i use.
Potting soil...............40%.
Perlite.....................30%
Top soil...................20%
Masons sand............10%
Top soil is where the bulk share of the nutrients are contained within soil,adding top soil assures a well balanced supply of nutes,the masons sand increases the bulk of the soil without taking away any real volume in the pot,it also add's drastically to soil drainage & oxygen delievery,just be sure to use "masons sand" only,if you use beach sand or playground sand it will kill your plants from the high salt content.
It's worth the time & extra cash to amend your soil the right way as it increases growth in all areas durring the grow.