It’s a couple things……..One big reason is that the seed bank hasn’t been disturbed. The other reason is Joe has put down a thick mat of straw that’s shaded out the soil surface. His seeds are in a good place for germination and the only holes in the straw are the ones Joe is making to plant the seed. When farmers press large fields of cereal rye and drill into them with a drill, it’s the little cutters on the drill that create these openings in the mat of hay for just the seed we planted to come through. When I do throw and mow……the mowing part scatters and piles the straw in an erratic pattern instead of a nice flat mat. That leaves me space between the straw pieces for the new seeds I just threw down to penetrate through before the hay settles down to the soil surface.

Don’t think it’ll stay weed free forever though. You’re just getting a head start. As soil temps warm more and more and the hay degrades….you’ll eventually have some grasses and weeds start penetrating through. You want to use the vegetables you’re planting to shade out the soil surface so that no new grasses and weeds can see sunlight. You want to plant things thick enough that you don’t have a bunch of empty space. You’re putting a canopy over the soil surface…..shading it out. This also keeps soil temps cooler and preserves moisture. You could scatter a little more hay in the gaps as the summer progresses if you want to.