Composts

[Eric Williams]

Just a thought on a rainy day. Nearly all of us have out own mix when it comes to growing cacti. Nearly all different but “ it works for me “. I wonder how many use the old what I call traditional mix of John Innes and grit. When I started growing over fifty years ago, nearly every book mentioned this mix. The only other change was for Ariocarpus. Thanks

[MatDz]

I was about to start (yet) another thread on potting mixes, but will leave a comment here because why not!

I really struggle recently to find a decent peat-free alternative to the good old JI (although JI also varied a lot between brands, SylvaGrow used to be fine, while Levington and Westland always had more rubbish than compost in the bag)! The last few ericaceous compost bags I bought were very "lumpy", and the sieve I used earlier for SG JI left barely anything for the plants...

Given this, I am considering switching to the "raw" materials I could use straight from the bag: fine grit, fine moler clay, (sterilised?) loam and some coco coir or other organic matter, which exactly is still TBD. I am just slightly worried about pH of such mix, which might land on the neutral to slightly alcaline end, so not ideal.

[Tony R]

... I wonder how many use the old what I call traditional mix of John Innes and grit. ...

I do! Perhaps showing my age too!
The majority of my plants are potted these days with Westland No.2 JI and RHS Potting Grit (bagged by Kelkay), ca. 2:1 to 1:1 mix depending on plant.

Current batches of Westland No.2 in the south-east are 'good' for me
Remember different parts of the country may get 'different' Westland product - I think - they are not all manufactured at one site, reflecting legacy companies, and to reduce transport costs, so are dependent upon local quality control and practices.

[DanielAdkins]

I was also using a mix of 2 parts horticultural grit to one part JI mainly. But now I can't find a good JI peat free replacement (run into many problems with the peat free JI). So I am now experimenting with a inorangic mix, which is showing very promising results at the moment.

[MikeT]

Current batches of Westland No.2 in the south-east are 'good' for me
Remember different parts of the country may get 'different' Westland product - I think - they are not all manufactured at one site, reflecting legacy companies, and to reduce transport costs, so are dependent upon local quality control and practices.

The Westland JI2 I bought last year in Sheffield was as good as any for several years. The same label stuff I bought earlier this year from the same garden centre was horrible: lumps of wood and chipboard, half composted plant remains, mixed with fine silty stuff that stains fingers (very different to the way 'normal' compost or soil does), bits of plastic (typical composted 'green' waste). I won't be buying Westland again.

I've now started to mix my own garden loam (not sterilised) with Sylvagrow (which has a few small bits of wood, but so far seems plastic free), grit and baked clay granule cat litter. Feels and looks good when mixed, I've yet to see how the plants respond.

[Diane]

A local garden centre stocks Growmoor compost which still contains peat (not Growmore!) so I tried a 10L handy pack. It’s lovely stuff! So I’ve now purchased a 35L bag, which I hope will be the same (unopened yet). It claims to be ‘reduced peat’, but the manufacturer also makes peat-free compost. It’s not a brand that seems to be commonly available, but if you see it, give it a go.

[Bonsai2]

I have been using the traditional JI2 or 3 plus 2-4mm RHS grit since I started with Cacti and succulents in 2018. In the last year or so I have found the quality of JI by a number of suppliers to be very poor and have found in the bags twigs, stones, live roots, conifer cuttings and glass. Now that peat has been banned some of the alternatives being offered contain wood chips or pairings which in my opinion are not suitable for cacti and succulents. Since the quality of JI has become poorer I have started to microwave the mixed substrate for 5 minutes before potting or repotting.

I have moved from Cactus to Mesembs and have 24 species. Roughly 50% are winter growers and of the 200 plants, I have now repotted almost 100 in pure 2-4 mm Pumice. After 4 months, I am pleased with the initial results and will further test for a year or so. I feed every month with Maxicrop Seaweed Fetiliser at 1/4 strength during their growing seasons. While Pumice is more expensive, it is reusable after washing which will cut down the costs when repotting.

[SimonT]

Most of the compost I use is now peat-free and this works fine for most of the plants I grow.

But I still use Westland JI plue grit/drainage for C&S although I'm testing some options to replace the JI with a peat- free version.
I'm just trying to swap the JI I currently use from Westland for the Westland peat-free equivalent.
I'm also trying Sylvagrow John Innes peat-free as a base in a similar way.

It takes so long to test changes to compost. It took me several years to compare two previous compost mixes.
Then for most of the plants I tested it didn't make much of a difference whichever compost I used.
However, for one species one set of test seedlings died off, while in the other most survived!
I'm not reading too much into this other than there is a need to do long-term tests first before moving everything over to a new formulation.
Otherwise bad stuff can happen even if it takes a few years to show up...

[topsy]

Might as well add to the comments.

I still use traditional JI3 + grit/sand, 60:40 for all my mesembs and many other succulents.
For the cacti we use JI3 plus, moler clay granules, extra food in the form of hoof, blood & bone, perlite, rock dust, and perhaps some vermiculite, proportions vary.
The brand of JI3 we use and a number of other branch members use is Clover, which at the moment is not peat free but that will end at the end of 2023.

The JI3 is so good and reliable that we do not have to sieve it as we have done in the past with other brands. If you can get it Erin is just as good. As this name might suggest it comes from N. Ireland as does the Clover brand.

Suzanne & Tony Mace

[MikeT]

I'm not reading too much into this other than there is a need to do long-term tests first before moving everything over to a new formulation.
Otherwise bad stuff can happen even if it takes a few years to show up...

We have a problem, though, because although the label on the bag might be the same, what's inside is a big change to a new formulation, whether we like it or not. The option of keeping to the same formula has been taken away from us.