The Horticulture Code of Conduct is a mandatory industry code made by regulation under Competition and Consumer Act 2010. Section 51AD of that Act states that a person ‘must not, in trade or commerce, contravene an applicable industry code’. You can consult the current Code here: Horticulture Code

The Horticulture Code regulates the conduct of growers and traders of horticulture produce in Australia and provides a fair and equitable dispute resolution procedure for disputes that arise between them. 

Growers grow horticulture produce for sale to traders.

Traders are merchants who purchase horticultural produce from a grower or agents who sell horticulture produce on behalf of a grower.

Horticulture Produce is defined (in clause 7) to include:
     (a) unprocessed fruit;
     (b) unprocessed vegetables, including mushrooms and other edible fungi;
     (c)  unprocessed nuts;
     (d)  unprocessed herbs;
     (e)  other unprocessed edible plants.

But not nursery produce like trees, shrubs, propagating material or flowers or foliage.