I followed Toby Hemenway's instructions in his book Gaia's Garden for sheet mulching. I live in a drought area with about 11 inches of rain per year and I wanted to create beds that needed less water, I didn't have enough wood for a hugelkultur bed. I used the same materials as Tody describes but instead of the 8-12 inches of hay, I used straw, and only about 2-3 inches and on the top I also used straw. I used straw instead of hay because I thought straw was dead and it wouldn't germinate seeds. It's been about a week and a half and now straw is growing in between my plants.
On another bed, I followed his instructions exactly and used 8 inches of hay in the middle layer and then straw on top. I hope this one turns out better. But, I'm afraid the straw or hay is going to germinate too!
On closer inspection of the straw, I found seeds in there. My little plants are very happy, but now what do I do with all the grass growing in between? I was thinking of putting cardboard on top and cutting holes for the plants and then putting wood mulch. (because now I am scared of straw/hay)
Where did I go wrong?
http://tobyhemenway.com/resources/how-to-the-ultimate-bomb-proof-sheet-mulch/