I doesn't look bad to me. It is new floor, so it doesn't have the patina of aged wood.

Pine does not stain evenly. Let it settle and maybe buff it. Over time it will look better.

Thanks, @houssaon. How does it change over time? Does it get lighter or darker or just kind of even out? It would be helpful to know what to expect.

I’m no help with your flooring problem but just had to say your original flooring is so, so beautiful.

Pine HATES taking a stain! Like HATES it. As in, "The floor looks like it has the measles" type of hate.

Here's my two cents on the issue:

1. Be VERY CAREFUL when doing a 'buff and coat' over an old floor like this. You *might have shellac as the finish (super old fashioned type of finish = bug-produced resin secreted by the lac bug (no I'm not kidding). It is then dissolved in alcohol to produce a 'finish'. Shellac resin ranges from light honey to deep mahogany. This is probably why your floors have deeper colouring than traditional polyurethane. Be VERY CAREFUL with this old finish. Very very careful. If you apply the wrong product to the old shellac (assuming that's what it is) you run a HUGE risk of ruining what you've got. If you like it, leave it alone.

2. Do NOT stain the new pine. Just use an old fashioned oil based finish on it (three coats) and then let it 'off-gas' for 30+ days. Once it has fully cured the ambering will begin. Or, if you are determined to have your floors match as close as possible, you may have to pay the piper and get in an OLD FASHIONED FINISHER who KNOWS how to create/work with shellac (the original stuff). The refinisher can then mix up the right colour for your new floors.

In other words you are better off leaving your floors alone. No new polyurethane on old flooring and no stain on new flooring.

Your original floors has a stain on it. You will need to stain the new to match the old. Stain layering will be your best option. Apply a dye coat, then layer it with a stain. The sanding needs to be done better. Pine is porous, sand it to 180 grit if, you need to. It will absorb the stain and poly, no problem. The fine sand...I've said too much.

Thank you, @G & S Floor Service. I actually came across this image of yours when I was researching how to resolve this problem. That floor is beautiful. Could you recommend a dye and stain combo that would work for my floors?

Thank you, @SJ McCarthy. I read about shellac after I saw your comment. I'm going to test the original floors with some denatured alcohol to see if they have a shellac finish.

Those floors was finished with Bona Provincial And Bona traffic hd satin. It needs the fine sanding as I mentioned earlier. It helps to eliminate the bl...,the flooring is antique pumpkin pine.

Your original floors looks like hard pine. The new floor that was installed is eastern white pine. Both will stain differently.

@G & S Floor Service, I was told the original floors are Eastern White Pine, so that is what we bought for the new areas. The house is in Northwest Connecticut.

My understanding is that pumpkin pine is a name for the Eastern White Pine that has developed the orange patina over time. Is that correct? What is the best way to imitate that patina on new pine?

Yes, that is correct. Pumpkin pine is 100 year old white pine.

The best way to imitate the patina is to use layer stains and finishes. You will need a combination of stain and pigments. A light base stain color, then different shades of pigments (Mixol) would need to be worked in here and there. Pigment would need to be added to top coats also. It becomes artwork and a PITA if, you do not have the patience.

Matching what you have, keep it simple. Dye the floor with General finishes "light brown" dye. Then go over it with either golden oak or early america oil stain and top it off with oil base poly.

IMO there is no way new pine floors will ever be the same as old pine floors they are actually even in many ways different wood. This will require a really good floor refinisher and a lot of hard work to get even close to what you have . Patina is by its nature time .

Keep it even simpler and find some cool retro patterned Lino

New growth vs old growth wood. You need to find a salvage Co that sells salvaged pine flooring. Your contractor simply laid down modern pine wood which doesn't act or look like the old growth that is there. New floor is soft and takes a dent easy?

Look for local wood salvage Co and flooring expert who can finish to match. You dont have that person right now.

@Brian Gannon, I discussed the floors with my contractor before he bought the material, and he assured me he could make the new pine look very similar to the old pine. I wasn't expected a perfect match (I am an old house lover, so I'm very familiar with the superiority of old growth wood), but I trusted that he was telling me the truth. I have refinished many floors in my life, but I have never done this type of pine, so I didn't realize how problematic it was. I certainly would have gotten reclaimed wood if I had known, but I think that's out of the question budget-wise at this point.

I would paint that floor. You will still have the texture of the wood floor; a painted wood floor is a time honored tradition in older homes and it won’t look like you are trying to match something you can’t!

...

Budget friendly too!

It is also the perfect finish of new flooring that is fighting a match...i think staining is the best way to go..(maybe start with a orange/ brown shade)... the new floors almost look patterned with all the colorations...so just getting them darker would be a start in the right direction...as a last resort ....painting is an authentic option..(that I personally love)...but any color or even a pattern should be considered...after getting the wood surface a darker color you will have the also authentic option of sanding a little to give the “worn/old floor” look...all of your options will call for an artistic as well as colorist schooled worker...try lookin at HOUZZ photos...”old painted floors” for ideas

Lynartist.. nice examples.. HOUZZ search not helpful

The squares can also be done with alternate wood squares ..not all paint

You will find more examples on Pinterest btydrvn! If the adjoining room has a painted floor in a diamond pattern it will look more intentional. Nobody will know this is a new floor that has been added. Right now it looks very obvious as the wood is quite different and I don’t think any amount of stain will make it match!

Here you go

Here you go or wait for the screams about painting wood 🙄.....

IMO a apinted floor even in a bedroom wears very quickly and I would say to that idea. But maybe for now do some flooring that can be layed over top of what you have like a loose lay lino and then when money frees up you can get the proper work done to make it match.

Here you goi had one that lasted for years!

I know.....We are all getting too predictable!...never mind the whole point is for the paint to look worn...

🤷🏼‍♀️

Yup, that what gives it its charm!

Thanks, @Business_Name_Placeholder! I like the look of painted floors too. I will think about that for some of the rooms with new pine