Our soil test showed that there is a marginal level of lead on our garden site - its not high enough to get freaked out about, but we still want to play it safe. Since lead accumulates in leaf and root tissues but not in the fruiting bodies of plants, we've decided to grow all of our leafy greens and root veggies in raised beds with imported compost from off site.
This means the area that we sheet mulched will be reserved for tomatoes, peas, beans, squash, and other fruiting plants. Maybe some berries?
Our sheet mulched area is in the sunniest part of the garden, so our roots and shoots will just have to make due with some part sun and dappled shade closer to the apple tree.
Kate, Ashley, and I met at the garden recently to take some measurements and brainstorm some ideas. Depending on how much materials and compost we can fit into our budget, we'll hopefully be able to set aside about 150 square feet of raised beds.
For more on lead in garden soils, go to
this link.