Parliament passed a law legalising recreational marijuana on Tuesday but it still needs to be implemented.
The law was expected to go into effect on 1 July, but the bill was delayed by Senate revisions.
The provinces then asked for extra time to plan how to regulate the sale of marijuana to the public.
"I think we all agree that it's important to get this right and not rushed," Mr Trudeau told press Wednesday afternoon.
The bill still needs royal assent from the governor general, which is likely to happen soon.
The federal law makes the sale and recreational use legal, but how it will be sold is up to provincial governments.
Adults over the age of 18 will be able to possess up to 30 grams (1 oz) of dried cannabis in public. But most provinces have raised the minimum age to 19, often in accordance with the legal drinking age.
The bill is not without its critics.
The Senate had asked for 40 amendments to the original bill, including one that would have allowed provinces to ban home cultivation. The government rejected that amendment and 12 others, and the Senate ultimately conceded.
The bill that passed allows for people to grow up to four plants at home for personal use. Two provinces, Quebec and Manitoba, still intend to outlaw home cultivation.
Justice Minister Jody Wilson Raybould told media on Wednesday that it was not the intent of the federal government to challenge provincial laws regarding home marijuana growth, but that the issue could wind up in the courts if an individual were to present a legal challenge.
Conservative Senator Larry Smith chastised the government for "failing to educate" children about the dangers of cannabis use ahead of legalisation.
"As a teacher, the Prime Minister should know that education doesn't happen overnight," Mr Smith said in a statement.
Others have criticised the government for continuing to enforce prohibition until the law comes into force and have asked to grant amnesty to those convicted of minor drug infractions between now and 17 October.
But Mr Trudeau said it was "illogical" to start talking about amnesty and pardons before the law is changed.
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