Olla Irrigation With a Desi Matka: Buried Clay Pot Watering
Olla irrigation is the oldest drip system there is: bury an unglazed clay matka up to its neck beside your plants, keep it filled, and water seeps slowly through the clay into the soil around the roots. In a Multan or Lahore summer it can turn a bed that needs watering twice a day into one you top up every couple of days.
Quick facts
- Pot: plain unglazed clay matka or ghara, 5 to 15 litres
- Must: no glaze, no paint, drainage hole sealed
- Depth: buried with only the neck, about an inch, above soil
- Spacing: one matka for roughly a metre of bed, planted around on all sides
- Refill: every 2 to 4 days in summer, weekly in winter; check, don’t guess
- Best crops: gourds, tomato, brinjal, chillies, bhindi
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How does a buried clay pot water plants?
Unglazed terracotta is full of tiny pores. When the soil around the pot dries, it pulls water out through those pores; when the soil is damp, the pull slows down. So the matka feeds roots at roughly the rate they drink, which is why it wastes so little. North Dakota State University Extension notes that glazed or plastic pots will not work at all, because nothing can pass through them.
Roots soon find the pot and wrap around it. Within a few weeks you will see the plants nearest the matka grow faster and wilt later on hot afternoons than plants watered from the top.
Which matka should you buy?
- Unglazed, unpainted, plain red or buff clay. Sprinkle water on it: it should darken and soak in within seconds. If water beads up, it is glazed or sealed.
- Thin walled and evenly fired. Tap it; a clear ring means no hidden crack.
- Size by bed. A 5 to 7 litre pot suits a large tub or small bed; a 10 to 15 litre ghara suits a ground bed of gourds.
- A lid. A clay saucer or a flat stone stops evaporation, mosquitoes and lizards.
How do you make an olla at home?
- If your matka has a drainage hole, plug it. Press a flat stone or tile piece over the hole inside and seal around it with a little cement or silicone, letting it harden for a day.
- Fill the pot with water and leave it on a dry floor for a few hours. A damp patch spreading evenly across the outside means it works; a jet or drip means a crack.
- Dig a hole in the bed a little wider than the pot.
- Set the matka in so only its neck, about an inch, stands above the soil. Backfill and firm the soil all round so clay touches earth everywhere.
- Fill to the brim and cover with the lid.
- Sow seeds or set seedlings 15 to 30 cm from the pot wall on all sides.
The two pot trick
If you only have small flower pots, join two of the same size mouth to mouth with silicone, seal one drainage hole and use the other as the filling hole. The result is a mini olla that fits a 30 to 40 litre tub. Cover the filling hole with a coin or pebble.
How far apart should ollas be?
A matka wets a ring of soil around it, and the size of that ring depends on your soil: wider in clay or loam, narrower in sandy soil. Extension sources do not give a fixed figure, so use this as a starting rule and adjust: in a typical Punjab loam bed, place one medium matka for about every metre of bed, and plant around it on four sides. In sandy Bahawalpur or Thar soils, place them closer. Dig a test hole a hand’s width away from the pot after a week: if the soil is damp at root depth, your spacing works.
Which crops suit matka irrigation?
| Plant | Maybe | Skip |
|---|---|---|
| Lauki, tori, karela, kheera: big thirsty vines | Leafy greens, which thrive but need the pot’s top up | Carrots and mooli right against the pot (forked roots) |
| Tomato, brinjal, chillies, bhindi | Young fruit plants for the first two years | Desert plants and succulents |
| Melons in summer beds | Herbs like basil and mint | Rosemary, lavender, which hate damp roots |
How often do you refill an olla?
There is no fixed schedule, because it depends on heat, soil and how big the plants are. Check daily for the first week and note how far the level drops. In May and June heat, with mature gourds around it, a medium matka may empty in two days. In the monsoon, the soil is wet and it barely drops. In winter, a weekly fill is often enough.
- Seedling stage: also water the surface lightly for the first two weeks, until roots reach the pot.
- Heatwave days at 45C: refill daily and mulch the bed thickly.
- Frost nights: fill in the morning, not at night. A full pot can crack if water freezes, though that is rare on the plains.
How much water does it really save?
Ollas cut loss mainly by watering below the surface, where the sun and wind cannot steal it, and by not wetting paths and weeds. How much you save depends on your soil, mulch and habits, so we won’t give a percentage. Most gardeners notice it in fewer refills and fewer wilted afternoons. Compare with our guide to watering pots by season if you grow in containers.
What goes wrong, and how do you fix it?
- Pot stops seeping: pores clogged with salts or algae. Dig it up after the season, scrub with a brush and soak in water with a little vinegar.
- White crust on the outside: salts from hard water. Use rainwater or stored water where you can.
- Roots inside the pot: a cracked pot. Replace it.
- Mosquito larvae: the lid was off. Always cover it.
The matka compost method uses clay pots in a different way, for kitchen scraps. More vegetable bed ideas are in Kitchen Garden.
An open matka of standing water breeds dengue mosquitoes within a week, so keep every pot covered with a lid that sits flush. Buried pot necks are a trip hazard: mark them with a ring of bricks if children play in the garden. Never put fertiliser, pesticides or soap in the pot water; it goes straight to the roots and can scorch them, and children may drink from it. Cracked clay edges are sharp; handle with gloves.
Olla irrigation: your questions
What is olla irrigation?
It is watering with a buried unglazed clay pot. Water seeps through the clay walls into dry soil around plant roots.
Can I use any clay pot as an olla?
Only unglazed, unpainted clay. Glazed, painted or plastic pots don’t let water pass through.
How do I seal the hole at the bottom of a matka?
Press a flat stone or tile over the hole from inside and seal around it with cement or silicone. Let it set hard before filling.
How far apart should ollas be placed?
As a start, one medium pot per metre of bed in loam, closer in sandy soil. Dig a test hole to check the soil is damp between pots.
How often do you fill an olla?
Every two to four days in summer and about weekly in winter, but check the level rather than following a calendar.
Which plants grow best with ollas?
Thirsty vegetables like gourds, tomato, brinjal, chillies, bhindi and melons. Drought loving herbs and succulents dislike it.
Does a buried pot attract mosquitoes?
Only if left uncovered. A flush lid keeps mosquitoes from breeding.
Can I use an olla in a grow bag or pot?
Yes, a small one or a two pot olla fits a 30 litre container or larger.
Do I still need to water the surface?
Only while seeds and seedlings are young. Once roots reach the pot, it does most of the work.