John Innes composts

[Paul D]

Over the last few years I've used various proprietary so-called "John Innes" composts as a base for mixing substrate for cacti. I settled on J. Arthur Bowers, which I found was reasonable, with a good loam component. They've stopped making it.
I tried Levington, which I found full of bits- rocks, bits of coir, etc., and I've just received some from Bord na Mona, which as far as I can see seems to be mostly peat and sand with fertiliser added.
None of it seems to be following the original John Innes recipes, and I know this has been discussed on this forum in the past. When I was involved with the Cruickshank Gardens in Aberdeen the head gardener used to make up his own John Innes mixes. So, I thought, maybe it's time I was doing that too. If you can't find what you want, make it yourself. I figured that combining the Bord na Mona stuff with 50:50 garden loam will give me a good base.
The John Innes component only forms about 25% of my cactus mix- so it's not too critical, but I prefer a loam-based compost. I have plenty of good loam in the garden, but will need to screen it, and sterilise it before mixing. Does anyone here use a sterliser? If so, which one, and is it steam based or hot element based?
Does anyone else make their own John Innes composts? Or do you have a tried and tested proprietary make that you recommend?

[Liz M]

I have become increasingly disillusioned with John Innes composts. The best I have come across is Westland's John Innes because it is well sieved and not full of bits and flows well. It has a higher proportion of peat than I would wish, from 40-70% it says on the bag but it always seems to contain a high proportion of peat. In despair I started making my own mix, this contains John Innes no 2,1 part, grit, 2 parts and home made loam, 1 part, (from rotted down turf) plus Tesco's catlitter,1 part, when I have it instead of one of the parts of grit. This provides a free draining and free flowing mix, so that it drops off the roots when I re-pot the plant. I also use half-strength fertiliser about four times in the year when watering. I feel that the home made loam provides a lot of nutriments that could be lacking due to the high proportion of drainage ingredients, plus the peat which provides next to nothing. My plants look healthy and where possible I put them outside to get the best possible light. Cacti mostly stay in the greenhouse, unless large enough and strong enough to grow well in our 'summers'. It seems that succulents don't really need that much nutriment, good light and drainage seem much more essential.

[Peter]

The best John Innes composts that I've used is the Keith Singleton's range. Keith's business is based in Carlisle. He delivers to garden centres as far south as Manchester but I don't know how far into Scotland he goes. I have spoken to him and he told me that he does not want to develop this side of his activities because he wants to maintain his quality levels. He said that he will deliver pallet loads to wherever in the country if people wish. My plants romp away when repotted in a compost based on his J.I.no3.

My backup product is Westland which as Liz states, is quite good. Bowers, in my opinion was awful. Since Westland bought Sinclair, the Bowers firm, the range of Bowers composts has been repackaged and is available in relatively small packs at my local garden centre. It may possibly now be the Westland product but as it says Bowers on the bags I won't be trying it.

[DaveW]

Bord na Mona is an Irish peat company that supplied peat for many uses, including mainly for burning in Irish power stations, though seemingly that is being phased out and it will just supply for horticultural use in future.

https://en.wikipedia.org/wiki/Bord_na_M%C3%B3na

As said in the past, there is no such thing as "peat free" John Innes composts, any that remove peat are really new formulations nothing to do with the original JI mixes and really ought have a new name since they are misrepresenting the product. If you used genuine JI compost in the past, but now don't like using peat, then the modern substitutes are a very variable lot, even containing semi rotted garden rubbish to replace peat.

Whilst semi rotted garden waste would continue to rot when used on our wet gardens I am not sure it will continue to do so in composts of pots of cacti and succulents in greenhouses which are allowed to dry out regularly, therefore the bacterial action to rot it may not be so active? In those cases peat mixes are more inert, as would be coir mixes.

Note there should be no textural difference between JI 1,2 & 3 other than the amount of fertilizer added, so whichever you use it will make no difference to how the mixture drains. According to the JI formula's for JI 1,2 & 3 Liz they should contain 25% peat by volume.

For those that want to mix their own, the JI recipes are here.

http://www.gardeningdata.co.uk/soil/joh ... _innes.php

The fertiliser in most commercial mixes has now been replaced with a general purpose one instead of the ingredients in the original recipes above.

[Diane]

My choice is Westland too - same reasons as Liz has said. Homebase's own brand is also quite good, which is my back-up if I can't get Westland.

[Terry S.]

I favour Clover JI compost, another product from an Irish peat producer. It doesn't seem to be widely available but luckily my local allotment society stocks it (and 4mm granite grit too). I also use Clover multipurpose for my streptocarpus and the improvement when repotting from better known multipurpose brands (reduced peat or peat-free) was very noticeable. I had problems with losing roots on plants or even killing them completely when using a particular batch of Westland JI and that put me off that brand.

Dave comments on commercially composted garden waste. I would not expect this to be only partially composted; it is normally composted rather quickly at higher temperatures than are usually achieved in home-composting bins. One consequence of the high temperature process is that it becomes alkaline whereas this doesn't happen with home-produced compost.

[cactuspip]

I have been a Westland devotee for some time now. I still find I need to sieve out the detritus that comes with the peat content, but what is left is really quite good. I find this applies to the seed and cutting J I equally with the no2 and no3. I wouldn't touch Levingtons with the proverbial barge pole. The last bag I bought of that looked just like their regular Multipurpose compost. I took it back and got a refund.
It made my day when I did a google search and found Homebase stock Westlands fairly locally.

[DaveW]

I bought some Ericaceous compost Terry and most of it was semi rotted garden waste, even some blackened privet leaves could still be seen in it. I think some of these garden waste recycling plants work on time limits in order to accommodate new material rather than if the process is 100% finished.

[Keith L]

If you have a B&M locally which has what they optimistically call a garden centre they have Westlands JI at a much better price than the "Everyday low price" claimed by the new Homebase owners - from memory less than £3.50 for a 30 litre bag.

Regards

Keith

[Keith H]

I like the B&Q own brand John Innes, I don't think I have ever found any bits of plastic or other rubbish it it just the odd small stone or two.