Blue Apron Holdings plans to start selling its meal kits in stores later this year, part of an effort to reach more customers as growth stalls.The New York-based pioneer of boxed meals still is very focused on its core online subscription model. But it’s also considering selling single kits on its website and is in “active conversations with a variety of retailers” to put its meals on store shelves in 2018, said Louise Ward, a spokeswoman.Blue Apron’s current offerings consist of weekly deliveries of two to four recipes for as many as four people.Blue Apron has struggled since going public last year, with its shares battered by Amazon.com’s push into the grocery industry and concerns about the subscription meal-kit model.