We put out fertilizer with ATV spreader, come right back and spread seed with same spreader and then drag, and the leave field. No reason you can't spread all with same spreader, just don't mix seed and fertilizer together, spread separate. Been doing this ten years on 22 green fields and no problem. We use triple 13 mixed with slow release nitrogen. Fertilizer comes mixed that way. Only use high end seed, contains rape, clover, radish and other small seed.