does anybody use this, or could someone tell me if it is worth trying pls. http://www.npk.ltd.uk/superslag2.htm
http://www.ebay.co.uk/itm/2-5kg-Basic-Slag-Fertilizer-/150464400644?pt=UK_Home_Garden_Garden_Plants_Fertiliser_CV&hash=item2308608d04
http://www.ebay.co.uk/itm/2-5kg-Basic-Slag-Fertilizer-/150464400644?pt=UK_Home_Garden_Garden_Plants_Fertiliser_CV&hash=item2308608d04