I often get asked "what's wrong with using softwoods for furniture making?" and the quick answer is .. well, it really depends on what you are making. You see, the term softwoods generally refer to woods that come from needle-bearing trees, whereas 

Watch it on Youtube: https://youtu.be/Y87hFgZI0MU

Hardwoods generally come from broadleaf trees. But these names do not always indicate the actual hardness of woods. Some softwoods are actually HARDER than hardwoods, and conversely, some hardwoods are actually SOFTER that than softwoods, so there is more to it ... 

Softwoods are generally used for building construction, and for that, they are ideal, easy to work with, and are plenty strong for their purpose. Hardwoods are selected for furniture making and similar things like floor because of the wear and tear they undergo over time. Building furniture from softwoods is OK for some things like tables for example because they don't undergo specific wear and tear like chairs, sofas, and the like. Another issue with some softwoods like Fir and Spruce is the sap that is contained in them.  Unless these woods are heat kiln-dried, some of these woods retain what is called "pitch pockets" and if the wood is only air-dried these pitch pockets can start to leak out of the wood through tiny cracks, and they can weep pitch for years and years. Imagine sitting in a chair and when you get up you feel a tiny "pull" on your clothing and then you see that there is a sticky wood pitch on your clothes from the wood. THAT is one of the other main reasons softwoods are not used for furniture. 
I the wood is properly heat kiln dried the pitch 'should' be crystalized and stable inside the wood (but not always).

Softwood Construction Grade VS Select Grade

So, aside from the strength issues of softer woods and their tendency to not withstand hard wear and tear, they can also spontaneously produce pitch pockets as in the picture below. In building construction, neither of these issues is a problem.

Softwoods still have plenty of woodworking abilities, they can still be used for select woodworking projects and things like shelving, woodworking jigs, boxes, storage, and tons of good uses. 

When you go to the lumber store, you will often see stacks of softwood like 2x4s, 2x6s, 4x4s, 1x4, 1x6, and so on. These stacks might be all the wood like Fir or Spruce or the could be a mix of softwoods referred to as "SPF"  Spruce, Pine, Fir and the stack of lumber could be a combination of all of these woods, there are no set rules on what goes into a stack of lumber, it depends on the lumber yard and how what they purchase. If you don't know ... ASK.

Softwood Left Construction Grade Right Select Grade169 4

I have already dealt with Pine in a previous article and video you can check that link out at the bottom of the article.

Here is Spruce, Pine, Fir ...

Softwood Left Construction Grade

There is not a huge difference between Spruce and Fir, particularly when you are talking about the Construction Grade versions. You see, you can also purchase their versions in a much higher grade of wood often called "Select". The Select is the best grade of softwood you can purchase, and it's often as expensive and good hardwoods. It is usually straight grain, no knots, kiln-dried, stable, moisture content of 10% or less, and quite a hardwood, almost as hard as many hardwoods. 
Construction Grade, on the other hand, will often be partially kiln-dried, expect a moisture content of at least 24% (too wet for many projects) but this can vary so you will need to check the moisture content. It will have nots, cracks, some warped boards, not the straights or the pretties grain and some will only be suitable for painting.

Below,  is Spruce Construction Grade on the LEFT and Select Fir on the RIGHT 

Softwood Left Construction Grade Right Select Grade

So ... can you use softwoods?  Absolutely, you just need to be a bit more selective about what you use it for, how you will finish, and most importantly, what will be the moisture content you will be working with. This is where being a "woodworker" really starts when you are selecting specific woods for a defined project and you are learning all the highlights and features about the wood and how best to use it and finish it. 

I often purchase extra construction-grade SPF even though it's too wet to use, and just leave it in my basement to slowly dry out over the next few months, then I have it use when I need it. I don't have a ton of it, but always a few pieces of 1x6 that I have hand-picked from the pile of lumber. 

 Check out the Working With Pine article HERE