A gap of about 1 1 2 to 2 inches between slats is the happy medium that allows the mattress to breathe while providing enough support to keep you comfortable.
Best wood for mattress support.
You can even get creative.
This includes cherry mahogany and pine.
A mattress foundation or bed frame is the support system you use to hold up your mattress.
This most likely will be an inexpensive construction grade of softwood such as pine larch douglas fir or spruce.
Plywood gives sturdier support for your mattress all throughout the night.
Basic wood types for slats most do it yourselfers building a platform bed for their queen mattress will go the local lumberyard or home center and pick up slats in whatever standard lumber species is available.
Plus it works well with any type of mattress like latex spring and memory foam.
The idea here is to provide that most optimal of support for all types such as hybrids spring and memory foam mattresses in full.
Softwoods are not usually used to make slats as they bend and bow and are not as resistant to pressure or weight.
A box spring is the most popular type but there are other types of foundations like platform beds and slatted frmaes that you can place your mattress on to raise the height of the bed and protect your mattress to get the most out of its lifespan.
Any wood that is easy to work with and relatively strong will do.