There is often a need to fill holes in wood before staining. One of our viewers asked, how do you get the filler to take the stain evenly with the wood alongside it?
The old trick of glue and sawdust is a sure stain problem, the glue will not take stain at all. Plastic wood is also a very poor choice.
The best effort is a non-waterproof (so that the stain can soak in) filler that is as close as possible to the original wood colour before staining. Many wood puttys are now pre-stained. Don't go for the final look but rather to match the original un-stained wood. Always test first on scrap: let the filler dry completely, stain and apply the final finish before judging if it works or not.
If you are repairing a piece and need to fill in a hole, then you want filler that is as close as possible to the final look. Remember to test with a clear finish over the filler before deciding if it matches or not.