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.ads-software.com.
The difference between the two types of WordPress (WordPress.com and www.ads-software.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!