How to prepare soil for blueberries
Hi! I am preparing 10" raised beds to include blueberries, and I have a 50:50 mixture of topsoil and leafgro that I thought I would use to fill the beds. The underlying soil was tilled to about 6". I also have a boatload of hemlock pine mulch sitting around that I could use if I need to. My Univ.Del. Soil Test Report says my soil's pH is 5.2, and index values are: P = 6; K = 46; Mg = 74; Ca = 40. In lbs/acre, my B = 0.4; Mn = 98.6; Zn = 3.3; and SO4-S = 19.8. I have 1.6% organic matter. My questions are: 1) Should I mix my existing soil with my topsoil/compost mixture or is it better to layer the topsoil on top of the existing ? 2) What nutrients should I add to the soil? Phosporus? Iron? 3) should I grow a cover crop this fall or maybe mulch with my pine chips?
If you have already purchased a 50:50 mix of topsoil and compost, we recommend mixing it into your existing soil rather than layering it on top. If you haven't purchased the mixture yet, we recommend just adding compost. Blueberries need a lot of organic matter to grow well and compost will provide this. We don't recommend planting a cover crop, since it will take time for it to die back/decompose in the spring when you want to be planting your new blueberry bushes. Mulch the soil with the pine chips for this winter and then pull back the mulch when you are ready to plant.
The following page on our website has information about growing blueberries. https://extension.umd.edu/growit/fruit-profiles/blueberries We don't recommend applying sulfur now, since your pH is good. In the first year after planting, you don't need to add any supplemental fertilizer. In year two, apply ammonium sulfate when the plants are in bloom and then three weeks later.