It will be written on the bottle!
But seriously, most fertilizers are better off used at half strength.
I also prefer to give fertilizers more often too, so, as an example, if it says once a week (at full strength), I have found plants much prefer 3 half doses over two weeks, that way they get a half dose every 5 days rather than a full strength dose every 7 days. This can also be prudent as it will almost guarantee that you won't burn your plants, especially useful when trying a new product for the first time. You will easily be able to tell what effect one half dose does, but giving it on its own and not mixed with your usual fertilizers will give you the most accurate feedback. By doing this, it will tell you if your plant can take more, or if it is too much, but far better to be too much at half strength than to be too much at full strength! Always tread lightly when trying out a new product for the first time.
It is very easy to give more the next time if half strength is not enough, but very, very hard to rescue a plant that has been damaged/burnt with a full strength dose of a previously untested and new type of fertilizer that you have introduced into your line up.
Also, you could always click on "nutrients" or "search diaries" on this site, to find out much more info regarding this, or almost every other product associated with cannabis cultivation.
Hope this helps, Organoman.