Abstract: In a method for prohibiting the growth of roots in the outlets of a drip irrigation hose, water under pressure is supplied to the hose for drip irrigation of the soil. A soil retainable, water transportable substance such as clay is introduced into the hose upstream of the outlets to form in the vicinity of the outlets localized regions containing the substance. The soil-retaining substance is also capable of absorbing a selected root-inhibiting, water-transportable substance. The selected root-inhibiting substance is introduced into the hose upstream of the outlets to distribute such root-inhibiting substance to the localized regions for absorption by the soil-retainable substance.