Mattress Forum

How old and soft is the box spring? A lot of the newer boxsprings don't really have much in the way of springs, so they actually could work pretty well.  An old one that has more in the way of springs and is broken in a lot, might not be the best.  Generally, latex is suppose to go on a pretty firm base (like the slats).  You can put a piece of plywoood over an old one (reduces breathing from the bottom though).  If you don't, then maybe you will have to go a bit firmer in the latex to offset the softer box spring (probably not the ideal solution though).
 

In buying a box springs, though, remember that not all of them are really box springs anymore. Many of the new ones are just boxes, made from wood with no "spring". (The spring isn't usually a "spring" either, rather it is usually a metal wire of thick gauge that serves to put some "give" under the mattress while also keep it flat.)