Re: Xbox 360 doesn't have enough memory to download Plants vs Zombies upgrade. Can't play without it.

Unfortunately it sounds like you have a 4gb hard drive, which by itself would be too small to be able to play Garden Warfare. Luckily we are able to use USB flash drives as hard drive space. Set up is explained here: http://support.xbox.com/en-CA/xbox-360/accessories/usb-flash-drive

After the flash drive is all set up and connected, when attempting to download the updates, there should be an option to change storage device; in which you select the flash drive.

Using this method, the USB drive must be in the Xbox in order to play Plants vs Zombies: Garden Warfare.