An experiment to determine weed spectrum, weed seedling numbers, temperature and nutrient changes in manure heaped for one to five months was undertaken over two seasons. Weed seedling numbers in manure heaped for one to five months decreased significantly by 65–70%. The weed spectrum comprised 17 broadleaf weed species of which Amaranthus hybridus, Leucas martinicensis and Nicandra physalodes were most prevalent. There were six grasses with Eleusine indica and Cynodon dactylon being dominant. Temperature increased from 20 °C in the unheaped manure to averages of 34 and 42 °C in manure heaped for three and five months respectively in the two seasons. In both seasons nitrogen and potassium became more available as the period of manure heaping increased while phosphorus decreased. It was concluded that heaping manure for three months significantly reduces weed seed viability and enhances the availability of some nutrients.