Irrigation designers generally do not target smallholders for drip irrigation and their standard low-cost kits are often ill suited to smallholders' diverse and evolving requirements. Incremental farmer-led innovation of drip irrigation may be more suitable for small-scale farmers. This chapter describes the different farmer-led adaptations of drip irrigation systems in greenhouse horticulture in the Algerian Sahara, in particular, locally built water towers to regulate pressure and facilitate the organisation of water turns, and micro-fertigation units catering to individual greenhouses. These adaptations have gradually been improved through re-engineering, and disseminated through networks of users and innovation intermediaries. This "innovation factory" not only produces technical innovations, but also local actors capable of adapting technology to new situations.