Pretty much as redundant in Japanese as it is in English. The festivity the artist is referring to is more commonly known as Jinjitsu. I suspect it was written this way as a pun: the seventh day of the month is pronounced as "nanoka", just the same as Rumia's famous catchphrase

The first of the Gosekku, it's a day to eat nanakusa gayu and pray for a year of good health!

Nanakusa gayu: a type of rice porridge made with seven seasonal herbs

Today, even Rumia will eat nanakusa gayu without meat!

Is... that so—? (Wants meat)

It is said that nanakusa gayu should be made with only the seven seasonal herbs, without meat, fish, or anything of the sort!