I have extra Sweet Peat left after topdressing the lawn. We bought several Hardy Hibiscus. The area where we want to plant them has rock hard clay. I was going to dig down and amend, but then I realized that when it rains, I'll have big bowl of amended soil soup! So, I built a frame from 2 X 8's and filled it with Sweet Peat. I noticed that the Sweet Peat was "steaming" when I dug into the pile and the filled raised bed is actually warm to the touch. The compost is still "hot".
So, what do you think? Can I plant directly in this stuff? Should I amend the Sweet Peat with some of that clay? Use some peat moss? See a movie? I sure don't want to fry my new Hibiscus plants!
By the way, I recently subscribed to this site. I've been skulking around for a couple years learning a lot from all of you and finally subscribed so I can join the fun.
(Heavy Sigh), After sleeping on it I realized my question was one of desperate hope. I know I can't plant directly in that "hot" Sweet Peat. I guess I was hoping for someone to tell me some easy way to fix my situation.
After reading up more on Hibiscus, I realized there's more reasons to not use straight mulch. I need some soil in there to provide a good foundation for the roots, retain some moisture, and provide minerals that the plants need.
So, I'm going to remove the Sweet Peat, and bring in some good quality garden soil to plant in. Then, I'll put an inch or two of the Sweet Peat back on top.
How long can it stay hot? If it is actively composting, it ought to finish and then cool down pretty fast. If necessary, give it some nitrogen to speed it up. How soon do you have to get the plants into the gorund?
Personally, after it cooled, I would add clay and sand to the peat, both building the bed up and excavating it down 2-6". Just be sure to cut a drainage ditch from the lowest point in the new bed to a lower point in your yard.
Clay provides a "buffer" to absorb, hold and release dissolved minerals. Without clay, fertilizer would wash out as fast as the water does. Especially in a raised bed, you can afford some fine soil components since the raised part is bound to drain well.
Who the heck cooked up the term sweet peat? Just what is sweet peat? What is the tested PH of your sweet peat? Does it have any NPK or other organic facts on the label?
I would just naturally tend to think that 25% peat mixed with the top six to eight inches would be about right. I would use a small amount of low number organic fertilizer like 4-2-4 and then mulch heavily after planting. Water to keep the soil damp until the plants are well established.