Yes, each olla comes with its terracotta lid, which should be replaced after each filling to prevent evaporation and keep mosquitoes out.

Raw terracotta planting olla – natural irrigation pot for vegetable garden and planter

Raw olla close-up – clay porosity for slow water diffusion to the roots

Terracotta planting olla – passive irrigation for vegetable garden and potted plants

Raw olla in the vegetable garden – autonomous watering during the holidays

Olla to plant out in unglazed terracotta

18,90 €

Size	Price	Price per L	vs 15 cl
15 cl	18,90 €	126,00 €	—
30 cl	20,90 €	69,67 €	−45 %
50 cl	26,90 €	53,80 €	−57 %

This unglazed terracotta olla, made in Alsace, is planted directly into a pot or planter, lid included: water seeps through the wall as the compost dries out. Available in 15, 30, and 50 cl, from orchid pots to balcony planters.

Olla irrigation

Size : 15 cl

15 cl

30 cl

50 cl

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The summary

The three sizes: 15, 30 or 50 cl, from 15 to 18 cm tall.
Which pot it suits: the 15 cl for an orchid, the 50 cl for a planter.
The reservoir: 24 to 36 hours of diffusion from a full olla.
The material: Alsatian clay left bare, with no glaze or additive.
What you receive: the olla and its terracotta lid.
Before installation: soak overnight in a basin of water.

Bare terracotta water reservoir, to plant in a pot or planter

The Agrotonome raw terracotta olla is a clay reservoir made from Alsace clay, with no glaze or additive, which you bury in the compost of a pot or planter. It comes in 15, 30 and 50 cl, from the smallest for an orchid to the largest for a planter, and its reserve is released over 24 to 36 hours.

An olla is a small terracotta reservoir that you bury in the compost alongside your plant and fill from the top. This model is left unglazed, and it comes in 15, 30 and 50 cl, lid included, suitable for an indoor pot as well as a planter.

🏺 A completely bare wall

Water does not leave through a hole: it seeps through the pores left in the clay during firing. The rate of seepage depends partly on the water level inside the olla and, above all, on soil tension, that is, the force with which drying compost draws and holds water. The drier your compost, the more water it pulls through the clay; once moist, it takes almost none. The clay in this model comes from an Alsatian quarry and contains no chemical additives. Left unglazed over its full height, it also loses a little moisture to the air above the compost surface, and a mulch around the neck limits that loss.

🪴 Which size for which pot

You'll choose the capacity less on the plant's water needs than on the space available in your pot, since the olla needs to be buried almost entirely without crushing the roots. Allow for its height, 15 to 18 cm, plus a few centimetres of growing medium beneath the tip. The moistened zone around an olla is roughly twice its diameter, so about 16 cm for the 15 cl model and 24 cm for the 50 cl. A 30 cl olla with a 10 cm diameter is therefore well suited to a pot around twenty centimetres across.

15 cl, Ø 8 cm

Orchids, small pots, and houseplants. When full, it diffuses over approximately 24 hours.

30 cl, Ø 10 cm

Indoor plants and window boxes. Its reservoir lasts approximately 24 to 36 hours.

50 cl, Ø 12 cm

Balcony planters, with approximately 36 hours of diffusion per fill.

Several ollas

In a long planter, place one olla every 25 cm or so to cover the full length.

Line an orchid pot with sphagnum moss

The 15 cl size is designed with orchids in mind, as their bark grow medium leaves a great deal of air around the clay. If you press sphagnum moss against the wall of the olla, you give it continuous moist contact with the roots. This moss holds up to 20 times its own weight in water and rehydrates within a few hours before use. The olla then releases water into the sphagnum, which redistributes it between the pieces of bark.

Plant the olla before the plant, never into the rootball

An olla pushed forcibly into an already-planted pot will sever any roots it meets, and the clay tip can snap clean against a thick root. Fit it at repotting time, placed against the root ball rather than through it. In a pot already in position, dig a hole with a dibber at the edge, where the roots are finest, and never force the clay.

🛁 The first fill

Before the first use, soak the olla overnight in a basin of water. Clay that is fully saturated then releases moisture for longer, especially when the reservoir is small. Bury it in your pot, leaving the upper section protruding, this must remain accessible for refilling, then firm the compost around it by hand: it is this contact that allows water to pass from the clay into the soil. Fill it, replace the lid, and water the surface of the pot normally on that first day. A young plant or a cutting will only benefit from the olla once its roots have reached the wall, which can take up to a month: continue watering from the surface in the meantime. The guide watering your plants with an olla walks through each of these steps in detail.

🌿 The plants that benefit from it

Plants that like consistently moist compost benefit most from an olla. Indoors, these include ferns, calatheas and marantas, pileas, syngoniums, philodendrons, and pothos, as well as cyclamen and begonia. On a balcony, the olla suits fuchsias, busy lizzies, and hydrangeas in containers, as well as fruiting vegetables in planters such as tomatoes or peppers. Succulents and Mediterranean herbs, thyme, rosemary, and lavender, prefer to dry out thoroughly between waterings, so keep them well away from the olla. The guide everything you need to know about ollas traces the history of this technique.

Technical specifications

The essentials

Capacities: 15, 30 and 50 clThe choice comes down to the space in the pot more than the plant itself.
Dimensions: Ø 8 x 15 cm to Ø 12 x 18 cm30 cl: Ø 10 x 16 cm. Approximately 10% variation between individual pieces.
Diffusion duration: 24 to 36 hoursFor a full olla, from the 15 cl to the 50 cl, at the first filling.
Material: Raw terracotta, unglazedClay from an Alsatian quarry, with no chemical additives.
Weight: 0,25, 0,65 and 1,1 kgFor the 15, 30 and 50 cl sizes.
Winter: Frost-resistantIt can stay in place in an outdoor planter.

To budget for separately

A bowl of water: One night's soakingBefore first use, to saturate the clay.
White vinegar: For descalingWhen diffusion becomes noticeably slower.

In the box

1 raw terracotta olla, in the chosen capacity
1 terracotta lid

Capacities, dimensions, weights, diffusion times, clay origin and frost resistance: manufacturer's data, recorded on 07/10/2026. Moistened zone: indicative figures from the agricultural extension services of the Universities of Arizona and North Dakota.

Estimate your
delivery time

Terracotta item, fragile, packed accordingly. Unpack it carefully and check the wall before planting. Exact shipping costs and final delivery times are shown in the basket once your address has been entered.

Frequently asked questions

8 questions

6 key questions, 8 in the detailed view

What size should I choose for my pot?

How often does it need refilling?

Is the lid included?

Does it need to be soaked before first use?

How do I go away for a few days without watering?

It drains more and more slowly – why?

Can it be left outside over winter?

Can you add fertiliser to the olla?

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Olla to plant out in unglazed terracotta

The summary