Leave it as is in FFOF . It may burn upfront ( strain specific) but plant WILL ACCLIMATE to it in time as long as you do not add unnecessary amendments to that host soil . Very little watering is required upfront - as you do not want to cause a damp off situation that will kill it.
When i plant a seed into straight FFOF , i tend to scoop out a center plug area and fill that with HF or another MILD mix .... think sandbox for seedling start so seedling can begin growth without being overpowered in beginning of growth.
FFOF will feed a plant up to 6 weeks on water alone. It is that ammended right out of bag. So your “ feeding “ is covered already. Target 6.5 ph in watering and let it do its thing.
As a natter of FACT , FFOF can be your “ nute “ for entire grow ... all you do is top dress at certain intervals to keep it recharged as it becomes exhausted over time. Top dress new FFOF and water in ..... stupid simple.