That comes out to March 31, 2019. The game will even be cross buy compatible, so if you've already got Stardew Valley on your PS4 you just have to log in to the PlayStation Store and download it to your Vita. After announcing earlier this year it will remove the device from the PlayStation Plus program, it's been confirmed today the company plans to end production of physical Vita games for the USA and Europe at the end of the fiscal year.
Sony set a deadline of June 28, 2018 for all product code requests, with a February 15, 2019 cutoff for final purchase orders.
Sony themselves demonstrated that when they announced they drop the PlayStation Vita from the PlayStation Plus programme. While this means there won't be any new physical games being made for PS Vita in the West, Japan will likely continue theirs for a while longer.
Anyone who has played Stardew Valley on the Nintendo Switch can attest to how perfectly suited the game is to a portable gaming platform.
Kotaku first brought word of this new development, and a Sony spokesperson has since confirmed to the publication that PS Vita card production is coming to an end. During the handheld consoles first week of sales, Sony shifted 500,000 units in Japan and the USA combined. The digital storefront for Vita games will remain online for the time being.
Many credit Sony's decision to only support it's own memory cards which were pricey and had to be bought separately as well as the rise of mobile gaming on phones and tablets for the handheld's demise.