Not so much growing supplies as there are cannabis products like vape juices, dry herb vapes, creams, and plenty people convincing you to buy into their next best cannabis business.
Plenty of stalls with a large variety of products, you'll definitely discover something you've never seen before, even just out of curiosity.
The best part of previous expos for me was the contact sessions with some notable individuals in the community that give their 2c regarding certain aspects of the cannabis industry. Anyone from Schindlers will be good.
They didn't let anyone smoke any actual cannabis within the confines of the expo, not even in the huge smoking area that they had setup. This had upset a lot of rastas and even got themselves kicked out at one point.
Last suggestion would be to not go at around lunch time, it was kak busy with people walking shoulder to shoulder. Either go in the morning, chow lunch at 1pm, then go back if you want to see anything more, this tactic proved useful.