P&K need to be something that you have at good levels in the soil ahead of time if possible. Both of those take a little while to become available to the plant after you add them and you would really like for good levels to be available to your seedlings. I think P may take the longest but don’t hold me to that. At planting you ideally might just add a little bit of nitrogen…..it’s not good to put heavy N loads on brand new seedling sprouts and not necessary either….there’s no developed plants to be able to utilize heavy amounts of N….that will take a few weeks…..Heavier N applications really need to come a few weeks after planting when the field starts to become more established and plants are a little more mature. You just don’t want your field to be completely N deficient at planting. If you’re no-tilling and you’ve got a good reserve of OM built up and maybe you had some legumes growin…..then you’ve probably got enough organic N in the soil to get seedlings off and running just fine.

…….or just add 250 lbs of 17-17-17 at planting time.