The time is now that your third party opposition parties will be looking for signatures on the streets. According to a new post in Ballot Access News by Richard Winger, “New York City holds partisan primaries for city office on September 12, 2017. Petitioning for candidates to get on a primary ballot runs from June 6 through July 13”. Some smaller parties have to act soon according to that post:

• The Independence Party leadership already chose its favored candidate for Mayor on January 5, 2017. That choice is Paul Massey, a Republican who also plans to run in the Republican primary.
• The Conservative Party leadership chose its favored candidate for Mayor on May 17. That candidate is Nicole Malliotakis, who is also running in the Republican Party primary.
• The Reform Party leadership chose Sal Albanese for Mayor, earlier this month. He is a Democrat who plans to run in the Democratic primary.

Ballotpedia is an amazing website for information on ballot access for third parties too. Check out this key information for New York State:

In order to get on the ballot in New York, a candidate for state or federal office must meet a variety of complex, state-specific filing requirements and deadlines. These regulations, known as ballot access laws, determine whether a candidate or party will appear on an election ballot. These laws are set at the state level. A candidate must prepare to meet ballot access requirements well in advance of primaries, caucuses, and the general election.

According to the NYC government website:

Primary Elections are held so that voters registered with a qualified political party may select their party’s nominees to the general election for partisan offices. Because a primary is a party election, only voters registered with one of the parties qualified to conduct a primary in New York City may vote in their party’s primary.

General Elections are held to elect candidates to public offices. For partisan offices, nominees from the party primary elections appear on the ballot, along with independent candidates.

Also, see this video from Democracy Now: