04/06/2026
An olla is an unglazed terracotta pot buried in the vegetable bed with its neck above the soil surface. Water seeps through the porous walls directly into the root zone — no evaporation, no runoff, no watering can. The terracotta regulates itself: water moves faster through the walls when surrounding soil is dry, and slows when the soil is already moist.
A 5-litre pot irrigates a circle of roughly 50 cm around it. Three pots spaced about a metre apart can keep a full raised bed watered for four to five days in summer without any further intervention.
Setting one up takes ten minutes:
Find an unglazed terracotta pot, 20 to 25 cm in diameter — glazed pots do not work as the glaze blocks the pores. Block the drainage hole with a wine bottle cork and food-safe silicone sealant. Bury the pot to its neck, approximately 20 cm from the stems of tomatoes, courgettes, or salad crops. Fill with water and cover the opening with a flat stone or terracotta saucer to reduce evaporation from the top.
Within a few weeks, roots grow directly toward the pot and cluster around it. In dry spells, when the soil surface is bone dry, the olla continues diffusing water silently into the active root zone.
For kitchen gardens where watering frequency is the main obstacle to growing more, this is one of the most practical low-cost interventions available. 🌿💧🍅