The only time I have sprayed was when I first started the plot, and I will spot spray when needed. There is basically always something growing, and I just add the seed into what is growing. Basically to start with I would just spray this spring, and again late June, plant your brassicas early July, then toss winter rye and clover seed into the standing brassicas, then as the brassicas die off the winter rye grows in? Then come spring, the clover, and winter rye really take off, then the rye will die off early June, then I seed the brassicas into the winter rye and knock the winter rye over with a drag to cover the seed, then repeat again in the fall. The clover I would assume would continue to grow throughout the year. I had only planted the clover in my plot on year one.