What is the ruling on selling fertilizers?

Two types of fertilizers are distinguished:

1. Fertilizer resulting from the processing and transformation of impurities (najasat): This type is permissible to use, sell, and buy. 2. Fertilizer that contains the essence of an impurity without transformation: Its use is permissible, though disliked (makrooh), due to necessity. Shafi'i and Hanafi schools: Its use is permissible, though disliked. Maliki school: They permit the use of something that has become impure (mutanajis), but not that which is inherently impure (najis). Thus, they permit watering plants with water mixed with impurities.

Regarding the sale of impure fertilizers:

Hanafis: They permit the sale of animal dung (sarqeen) and droppings (ba'r) (which are inherently impure) for benefit, but do not permit the sale of human excrement (adhirat al-adami) unless it is mixed with soil and the soil predominates. Shafi'is and Hanbalis: They do not permit the sale of anything inherently impure. Malikis: Their opinions differ, but the relied-upon view is that the sale of manure (zibl) is permissible due to necessity, but not human excrement.

The preponderant view is that the sale of impure fertilizers is permissible due to necessity and widespread affliction (umum al-balwa), even if their essence has not transformed.