GROW BAG CONTENTS
The contents of growbags change from time to time depending on the availability of products. You need to check each time you buy one! This is especially important as more recycled composts are used.
Many of you will have purchased grow bags. But do you know what is inside them? In these times of peat conservation and enthusiasm for organic gardening, it is interesting to find out. Some of the well-known proprietary products (eg Levington, Westland, J Arthur Bower, etc.) might be labelled with the contents. But what about B & Q or Homebase? .
I find that the peat free bags dry out much more quickly than the peat based types. There is a huge range of other composts, including the multipurpose and John Innes types. Many of them consist of various mixtures of peat, composted bark, loam, water storage crystals, perlite , nutrients etc. The use of composted waste seems to be minimal. The contents listed below were obtained from the manufacturers, but they are changed regularly, so it is probable that these will not apply when you next purchase bags. It is only a guide to what I found at the time.
Homebase ' 85% peat, 15% composted bark. A slightly coarser grade of peat is used as this allows better drainage and air movement. A high potassium fertiliser is used (no quantities specified) as potassium plays an important part in flower and fruit production, especially tomatoes'
'Homebase peat free. '90% composted bark, 10% sterilised loam. Due to the nature of the bark, this compost is slightly more open in structure, and the loam acts as a fertiliser buffer' (I don't know what that means. I would be interested to hear from anyone who does).
B&Q bags are described as having at least 20% alternative sustainable ingredients (?), and, presumably, 80% peat (with a policy of long term reduction). Nutrients are also added. The 'enriched peat free' grow bags (they don't seem to be available in Abingdon) are only described as having 'slow release plant food'.