Hi @myrdodisen,
You can limit the number of posts that display on your home page (and therefore the number of possible rows) via its Writing Settings here:
https://wordpress.com/settings/writing/ssrkvarmland.wordpress.com
Increase/decrease the number next to “Blog Posts” on that page.
There isn’t a way to have a set a number of rows across devices. You could set a number of posts that’s a multiple of two, three, and four to create consistency across all devices, however.
As an extra note: I noticed that your site is hosted over at WordPress.com while this forum is intended for folk who are hosted elsewhere and running on the free software available here at www.remarpro.com.
The difference between the two types of WordPress (WordPress.com and www.remarpro.com) is an understandable and common point of confusion. If you’re unsure of the differences, then this guide gives a good overview.
As your site is hosted over at WordPress.com, the forums there are the best place for to get support. If you have any extra questions then please start a new thread on the Themes forum:
https://en.forums.wordpress.com/forum/themes
Thanks!