Axel Rudakubana, 18, refused to speak as he appeared briefly on Wednesday in Westminster Magistrates Court by video link from jail.
Rudakubana, who is also charged with murdering three girls and stabbing 10 other people on July 29, was charged on Tuesday with producing the poison ricin that was found in a search of his home, Merseyside Police said.
Police also found a document on his computer that included an al-Qaeda training manual titled: "Military Studies in the Jihad Against the Tyrants".
Ricin is derived from the castor bean plant and is one of the world's deadliest toxins.
Rudakubana had been charged in August with the stabbings in the community of Southport that police on Tuesday stressed had not been classed as a "terrorist incident" because the motive was not yet known.
Police issued the new charges of producing a poison and possessing a terrorism manual on Tuesday.
The stabbing occurred on the first week of summer holidays as about two dozen young girls danced to music by Swift at a community centre in the seaside town of Southport in northwest England..
Rudakubana was charged with three counts of murder in the deaths of Alice Dasilva Aguiar, nine, Elsie Dot Stancombe, seven, and Bebe King, six.
He was also charged with 10 counts of attempted murder for the eight children and two adults who were seriously wounded.
The stabbings fuelled far-right activists to stoke anger at immigrants and Muslims after social media falsely identified the suspect - then unnamed - as an asylum seeker who had recently arrived in Britain by boat.
Within hours of a community vigil to mourn the Southport victims, an unruly mob attacked a mosque near the dance studio and tossed bricks and beer bottles at law enforcement officers and set fire to a police van.
Rioting spread across England and Northern Ireland that lasted a week.
More than 1200 people were arrested for the disorder and hundreds have been jailed.
Rudakubana was born in Wales to Rwandan parents, police said later.
British media reported that he was raised Christian.
