Finding pine needles beneath a tree does not mean you have found ready-made potting compost. Fresh needles, partly decomposed litter and well-rotted material have different textures and uses.
Identify what you have collected before adding it to a container. A recipe referring to finished pine needle compost should not be read as an instruction to fill a pot with fresh needles.
Check the source and condition
Collect only where you have permission and avoid material whose history makes it unsuitable. Look for litter, contamination and unwanted plant material rather than judging solely by colour.
If you prepare leaf mould or compost, follow an appropriate process and allow the material to develop before deciding how it fits into a growing mix. Do not assume every batch will behave identically.
Record the amount used alongside the other ingredients. If a pot later drains poorly or dries unexpectedly, the recipe becomes part of the investigation. Choose the mix for the identified plant and container. A familiar natural ingredient is not, by itself, evidence that the finished root environment will be suitable.
The RHS leafmould guide distinguishes well-rotted material used in growing mixes from younger material used as mulch. It also notes that conifer needles break down slowly. Fresh needles should not be substituted for finished leafmould in a recipe.
Related reading: Pine Needle Compost: Preparation, Uses and Soil Mixes.