Blue light is generally recommended for growth of foliage, and red light for fruiting/flowering.

Any plant, maybe with some rare exceptions, will grow under either blue or red alone, but blue will generally give them the most opportunity to produce foliage and growth, if compared to an equivalent amount of red light; lumen for lumen

Your trees being so young, I think would benefit the most from blue light, just as youve set up.

Thanks for the advice, Cherokee.