As has been said, adding some MPC to the mix can lighten it which is especially suitable for many perennials.
Normally perennials will be repotted into fresh compost each year … trees and shrubs are likely to be repotted less … my practice over the years has been to use Levingtons JI No 3 more or less ‘as is’ for trees and shrubs … if they require a more freedraining medium (such as for figs, bay, rosemary etc) I add a proportion of fairly coarse horticultural grit.
I might add a proportion of leaf mould if I have some, particularly for ‘understory’ woodland trees and shrubs such as Corylus avellana and similar.
Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.
Another thing about MPC is that it breaks down into finer and finer particles quite quickly, and before long it’s almost dust … this means that it loses its moisture retentive properties, along with the aeration, and then roots become starved of moisture and oxygen.
But then what is the point of mixing it with anything on a long term container ? (Not trying to start any kind of argument by the way, just trying to understand )
That is a good question actually. We know it breaks down to almost nothing, but when added to soil, at the start of that process it makes the soil nice and open and amenable to root growth. At the end of the process most of it has disappeared but the remnants stay in the soil as humus, which is beneficial. It's a different matter when it is used as the sole potting medium, in the long term. (But for short term use e.g. bedding and potting on, it's great!)
"What is hateful to you, do not do to your neighbour".
Most things in MPC, particularly peat, are in a state that can be easily broken down and absorbed as nutrition by plants. I'd say 90% of what is there in MPC is easily broken down and absorbed easily and very fast The plants take it all up very fast and the 10% or so that is left is like a bit of moss. The plants have nothing to "hold onto" with their roots.
Whereas soil has lots of things in various stages of decomposition. The content can decompose only very slowly, and there are other things in it that do not decompose. It's a mix of various different things that are slowly decomposing a tiny bit at a time over a long time. So, the roots have something to hold onto for years. And to this we add nutrition as a slow release fertilizer.
However, mixing in a bit of MPC to it gives the plants that early boost needed to get established. That is why it is good to mix a bit of MPC in.
Peat is "in a state that is easily broken down and absorbed by plants," is what I wrote. What peat easily decomposes and breaks down into are the components that are easily absorbed as nutrients by plants. Read before you leap.
Other materials in normal soil are in a state that decompose and break down over a much longer time.
I think this thread should be stickied so people who are unsure about compost, as there are so many different types could refer to it. Unless theres something similar on the internet though its hard to know what is trustworthy.
Unfortunately, we don't have that system on this forum @Ynnead. I know they have it on other gardening forums though. It would be useful for quite a lot of threads - tomatoes, sweet peas, lawns etc
It's a place where beautiful isn't enough of a word....
I live in west central Scotland - not where that photo is...
Peat (and things like composted bark etc) don't really provide nutrients, even as they break down. However they are good at holding onto nutrients in a form that roots can access. I won't go into detail on it but we covered this at college many years ago, it's called 'cation exchange capacity' or CEC. Clay is also high CEC, sandy soil is low CEC.
"What is hateful to you, do not do to your neighbour".
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Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.
That is a good question actually. We know it breaks down to almost nothing, but when added to soil, at the start of that process it makes the soil nice and open and amenable to root growth. At the end of the process most of it has disappeared but the remnants stay in the soil as humus, which is beneficial. It's a different matter when it is used as the sole potting medium, in the long term. (But for short term use e.g. bedding and potting on, it's great!)
Whereas soil has lots of things in various stages of decomposition. The content can decompose only very slowly, and there are other things in it that do not decompose. It's a mix of various different things that are slowly decomposing a tiny bit at a time over a long time. So, the roots have something to hold onto for years.
And to this we add nutrition as a slow release fertilizer.
However, mixing in a bit of MPC to it gives the plants that early boost needed to get established. That is why it is good to mix a bit of MPC in.
only stuff that is water-soluble can be absorbed by the roots.
Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.
What peat easily decomposes and breaks down into are the components that are easily absorbed as nutrients by plants.
Read before you leap.
Other materials in normal soil are in a state that decompose and break down over a much longer time.
I live in west central Scotland - not where that photo is...