We have small gaps between a few planks. This is a result of houseplant plastic trays that have leaked water. All plants that once lived in our living and dining rooms have met an untimely death. There is no stain, just a few small gaps that I feel could be filled with some type of wood filler and stained to match the test of the floor. Am I correct or way off base here?
If the gaps are very small, less that 1/8″, I would just leave them alone.
All wood floors will develop gaps in time, and this just adds to their character. But if it really bothers you can fill them with a colored latex putty. Try the products at www.leevalley.com (prod. # 80K86.10). Be sure to choose a color only just a tad darker than the wood floor. You can mix these colors if you wish. But be sure to wipe off the excess right away with a wet cloth, then a dry one, else it will leave a dry dull smear on the wood. You could also use a non drying colored wax beaumontage, and wipe this off with odorless mineral spirits. Again at Lee Valley prod. # 53Z01.41.
The latex putty is easier and safer to use, but it will dry hard. You can use an artists brush to apply some floor finish to the filler after it has dried overnight. But if the boards are loose, or move seasonally this filler will crack and fall out. The non drying colored putty cannot be finished with a polyurethane, but will remain flexible for years.