Peat free compost as mulch

markrosssmithXZAbLwpt · May 2023

In the show last week Arit had a segment on peat free compost, during which I think she clarified how peat free compost shouldn't be used as a mulch, and implicitly saying that thinks like soil improver, bark etc should be used instead. The statement was prefaced by the context of supply and demand for peat free compost when the ban on peat arrives next year. But when the above was stated, the reason was not explicitly clear - is it because of the peat ban that mulching with peat free compost would be considered wasteful relative to the early higher demand for it? (Seems obvious) Or something else more technical?

Fairygirl · May 2023

I've not seen it, but my guess would be that it certainly would be wasteful, and also very very expensive compared to other products, but commercial composts also have additional food which isn't always needed. However, that wouldn't necessarily mean it couldn't be used, in the same way you could have used compost containing peat as a mulch. It would just be a waste as well, when it could be better used for plants that require extra nutrition. Those in pots for example, or for growing on annuals etc.

Butterfly66 · May 2023

Using any fresh purpose compost as a mulch is a waste as it’s not adding anything to the soil. It’s not adding enough substance to improve soil structure and the level of nutrients/fertiliser is negligible for any long term benefit.

Soil improver, composted manure, home-made compost etc is what you want as they are adding organic matter which will improve the structure of your soil which in turn improves its ability to retain/release nutrients and water to your plants.

Bark will take longer to break down than the above but when it does will have the same benefits

markrosssmithXZAbLwpt · May 2023

All makes sense, and similar to my own understanding. Thanks.
Mulched one border last year with some heavily discounted peat free compost and will see what happens with it this year. New to gardening and haven't yet tried the obvious alternatives (bark etc).

Dovefromabove · May 2023

I have never ever considered using bagged bought compost as a mulch. Far too expensive.

I use homemade either garden compost, well rotted manure, bought bagged ‘soil improver, or composted bark. Cheaper and improves the structure of the soil, which is what my garden needs.

Fairygirl · May 2023

I would disagree with that comment re home made rather than commercial - the main difference between commercial compost and home made is the added nutrition. It's also done at a higher temp so less chance of weed seeds which is a bonus, but other than that, it's made of the same stuff - ie plant material, or should be.
The biggest problem recently with many commercial composts is that they aren't always as good/consistent as they should be, due to some 'extras' appearing in it, whereas with your own, you know exactly what's going in it.

Home made compost would do nothing for soil structure either if it was that different from commercial stuff.

Nothing really wrong with using some of the crappy compost that's for sale as a mulch @markrosssmithXZAbLwpt, if you don't have your own, and you can get it cheaply enough. Some of them are useless for anything else anyway!

JennyJ · May 2023

I think the difference between homemade compost, bagged composted bark etc and potting compost is getting smaller, now that potting composts are made from things like bark, woodchip and green waste. The main differences will be the added fertiliser, possibly sand and/or loam (the latter if it says something like "with added John Innes" (which bugs me because JI isn't an ingredient, it's a formula for mixing potting compost), and it should have been composted down further (but I think in a lot of cases it isn't).

So "pure" organic matter is a better mulch, as everyone has already said. Spent compost that's been growing your tomatoes, bedding plants etc for a season is better used as a mulch than thrown away though, and you could use peat-free compost as mulch (particularly the cheaper kinds, or if you've got some that turned out to be rubbish for raising plants in) but it's not really the best choice..

Busy-Lizzie · May 2023

I have been using bought peat free compost as a mulch and it has worked well. I bought this house in France a bit over 2 years ago so I didn't have homemade compost. The soil is clay. For each bed I made I dug in lots of compost before planting. I went to OH's cottage in Norfolk in January as he was to have a hip replacement, he's UK resident unlike me. Before we left I thickly mulched my flower and rose beds with bought compost, mostly peat free, from the garden bit of the hypermarché. It wasn't very expensive, £2 - £4 a bag 40L. I have just come back to France and I'm pleased with the result. My plants have grown well and there are far fewer weeds than I expected. I don't see why it can't be used for mulching.

I also have a large shrub bed. I mulched that after I made it with bark chippings. They were double the price of the compost. Last autumn I was able to much with wood chippings as the EDF had cut down a lot of branches for their cables and I had some tree surgeons in to do some pruning. They had a huge chipper and they left me a pile of chippings.

I have read that roses don't like to be mulched with bark chippings.

Busy-Lizzie · May 2023

By the way, what is soil improver? I haven't seen in here in France. Seed compost is rare here too. We have cheap compost, expensive compost, peaty, peat free and ericaceous. The ingredients are all written on the bags which is something I haven't seen in the UK. I have never found anything but compost in the bags. On this site I have read of people finding glass, plastic etc in their compost.

Fairygirl · May 2023

It's usually manure @Busy-Lizzie, or a mix. There's a chicken manure which I used a very long time ago called 6X, which was very good. You don't need much either, for a whole bed.

JennyJ · May 2023

The glass, plastic etc is (I think) from composted green waste that hasn't been well-enough screened. I assume it gets in there because people have put it into their green waste bins.

It would be great to see the ingredients on bags of compost.

Soil improver can be composted green waste, bark, wood chip, manure etc or maybe a mixture (although manure is usually labelled as manure, presumably so that vegans can avoid it if they prefer to). In the UK garden centres and DIY places sell it bagged, for example https://www.diy.com/departments/goodhome-peat-free-beds-borders-soil-improver-50l/5063022070302_BQ.prd (not an endorsement by the way, just the first example I found).

Peat free compost as mulch

Posts