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Cultivation (growing techniques): JOHN INNIS COMPOST

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Started by: David Hoare

Go to latest contribution by Elizabeth Maddock, 21 November 2007, 16:00. Go to bottom of this page.

Contribution from David Hoare 14 October 2007, 18:29top / bottom of page

Alpine growers in Kent have been lucky, as we have had a good supply of top quality JICompost (Tunstall brand) untill now, they have stopped mixing it themeselves and are buying it in from Somerset. I have just opened a bag and it is BLACK as your HAT!! It has very little grit in it and it binds together a bit. Has anybody in the South West used this compost,Is it any good. I do not know the make Pehaps its time to get Trading Standard's to look at the make up of JI Compost around the country

Contribution from Val Lee 18 October 2007, 23:42top / bottom of page

Hi David, sorry the SWest has been slow to respond. I haven't used the compost from Somerset but suspect it will be made with the dreaded sedge peat - In my experience no good for alpines!!! I chatted with one or two members of the Exeter Group this evening and hope they will add their bit about the local compost. In devon we have Wessex JI, which is very variable, I use Arthur Bowers Ji 2 & 3 recommended by Gardening Which this Spring and so far it has been OK Its about 3.75 down here. I would beware of the black stuff for high alpines!!!! Good luck, Val

Contribution from Lorraine Birchall 21 October 2007, 20:05top / bottom of page

If you contact Tunstalls they should be able to obtain details from the compost manufacturers details of its constituents.


As Val Lee said the dark colour of the compost indicates that sedge peat could well be included within the mix. This is a fine grade peat/material which would serve to impede its drainage.

From our experience of trying to find the right composts for growing alpines and South African bulbs we have contacted several manufacturers, including Sinclair, Roffey and Petalshell, all who have beenmore than helpful in providing full details of the compost, including bulk constituents, nutrient status, pH and 'air-filled porosity'(AFP). The AFP being important to know as the greater the AFP the better the drainage.

Sorry about all the different boxes - I am new to this and have already lost the first text I wrote by putting in too many paragraphs ! Must try harder !!

Contribution from David Hoare 21 October 2007, 21:55top / bottom of page

Thank you for your thoughts on the Black Stuff.I suspect the best way to go is to mix it myself, If you can get some good steralized loam. Has anybody got a good recipe or should I ask Nigella !!!.I only grow Saxifraga & Primula Allionii,so nothing to fancy. Best Wishes David

Contribution from Chris Birchall 22 October 2007, 18:23top / bottom of page

David, your next problem will be getting a supply of good loam ! One of the reasons why some commercial growers don't use loam based composts is that they are unable to obtain a consistent supply of good quality loam (one of the other reasons is weight)

Contribution from David Hoare 05 November 2007, 17:42top / bottom of page
Found good JI2

I have at last found a very good JI2 @ 2-21p a bag in Surrey, near Gatwick Airport about 75min drive from Lyminge. If you tap in for full details The firm's name is Sporting Surface Supplies Ltd. (Hurstridge) They also produce top dressing loams for Cricket pitches etc, so they have good supplies of good loam.They sent a sample through the post to me, which looked and smelt just right. So the Black Stuff will go on the garden and mix in with my chalky soil. Best Wishes DAVID

Contribution from Elizabeth Maddock 21 November 2007, 16:00top / bottom of page
JI compost

I use JI compost merely as a base, usually No 2. I add as needed, leaf mould, grit, grit sand and powdered lime. This enables me to adjust the compost to suit the plant. For Primula Allionii, I would take the proportions as, 1 part JH 2, 1 part grit, 1 part leaf mould and a small sprinkle of powdered lime (in the form of tufa dust). I find primulas thrive on plenty of leaf mould

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