Hey, I don't know if you will still read or not. I think, in the movie, it definitely over simplified the situation. Technically speaking, he could have a shot to try grow the potato. But the chance is very low. Firstly, the main problem is loss of air pressure. The microorganism and even the potatos are killed not just the low temperature but the low air pressure. This can cause the cells being exploded or dried due to water evaporization caused by suddent loss of air pressure. Secondly, assume he kept some potatos in a secured place where it mainained the air pressure, and these potatos are not cleaned very well and they carries some soil microorganisms, then, Mark will need to find ways to re-culture these microorganisms. Unfortunately, he can't just use the microorganism from his fecal because the human gut microorganism is not suitable for plant growth. To re-culture the soil microorganism, it is triky and takes time, and Mark can evaluate if it worth it.

In sum, it really depends when the airlock blew off, mark kept some potats in a secured container that can hold its air pressure.

In the book it's explained that Mark uses a combo of human waste to compost and some earth microbes/bacteria that he had brought with him. When the airlock blew and the Hab decompressed it not only killed the potatoes so he didn't really have any available to grow but he also thought it had killed all the microbes. He could reproduce some with his own waste but there wouldn't be the same variety as he no longer had the rest of the crew waste and the Earth soil microbes which were important.

I'm 90% sure in the book that Mark later realises that some of these microbes actually did survive the decompression and started reproducing again but it probably wouldn't have been that helpful given the timeline of starving vs growing potatoes and again I'm fairly certain he couldn't grow the potatoes anymore because they got instantly freeze dried. The potatoes were actually the opposite of rotten as the Martian atmosphere would likely be a great way to preserve the potatoes.