For Karthigai Deepam, most Tamil homes light their agal vilakku with nallennai (wood-pressed sesame oil) for the rows of lamps, and keep pure ghee (nei) for the main lamp at the pooja shelf. If you want a ready blend, a deepam oil made from sesame, iluppai (mahua), castor and neem oils gives a steady flame across many lamps.
Karthigai Deepam falls on 24 November this year, and the lamps usually go up on the evening before, the day itself and the day after. Here is how to choose the oil, how much to plan for, and a few things families learn the hard way.
Which oil for which lamp
Nallennai (gingelly / sesame oil): the everyday choice
Nallennai (நல்லெண்ணெய்) is the oil most Tamil households use for daily lamps and for the Karthigai rows of agal. A wood-pressed oil that has not been refined or bleached burns with a calm, yellow flame and a light sesame smell. Our wood-pressed nallennai comes in 500ml, 1L, 2L and 5L, so you can use the same bottle for the kitchen and the lamps.
Nei (ghee): for the main lamp
Many families light a ghee lamp (nei deepam) at the pooja room or in front of the kolam at the doorstep. Ghee burns slowly and with very little smoke. It costs more, so most people keep it for one or two special lamps rather than all of them. Thinai Ghee is available in 250ml and 500ml.
Deepam oil blends
Temple-style lamp oils mix several oils. Thinai Deepam Oil blends cold-pressed sesame, iluppai (mahua), castor and neem oils, and is made only for lamps, not for cooking. It is handy if you light many lamps and want one bottle that is set aside for pooja.
Vilakkennai (castor oil) and coconut oil
Castor oil is called vilakkennai in Tamil because it was once the common lamp oil. It is thick, so it needs a good cotton wick. In Kerala homes coconut oil is the usual lamp oil. Both work; the choice is mostly family custom.
Tips for lighting agal vilakku
- Soak the wicks. Dip cotton wicks in the oil for a few minutes before placing them, so they light at once and do not char.
- Fill about two-thirds. A brimming agal spills when you carry it. Top up halfway through the evening instead.
- Light a test lamp first. On the first evening, see how long one agal lasts with your wick and oil. That tells you how much oil to keep ready for the next two days.
- Keep ghee and oil lamps separate. Many families do not mix ghee and oil in the same lamp; use separate agals.
- Mind the flame. Place lamps on a plate or tray, away from curtains, sarees, dry leaves and children's reach, and never leave a lit row unattended.
Lamp oil vs cooking oil
Use a separate bottle of oil for lamps. Pouring from your cooking bottle with oily hands or a used wick nearby spoils the oil you eat. If you want to know what wood pressing changes in the oil itself, read wood pressed oil vs refined oil, and for ghee, A2 cow ghee vs regular ghee.
Everything for the festival, from nallennai to ghee, is in our wood-pressed oils collection, and lamp and pooja items are in Pooja Products. Order by the third week of November so it reaches you before the lamps go up.
Frequently asked questions
Which oil is best for Karthigai Deepam?
Nallennai (sesame oil) is the most common choice for the rows of agal vilakku, and ghee is often used for the main pooja lamp. A deepam oil blend also works well if you light many lamps.
Can I use ghee in all the lamps?
Yes, but it costs more, so most families keep ghee for one or two special lamps and use sesame oil for the rest.
Can I use cooking oil for vilakku?
You can use the same type of oil, but keep a separate bottle for lamps so your cooking oil stays clean.
What is vilakkennai?
Vilakkennai is the Tamil name for castor oil, so called because it was once the common lamp oil. It is thick and needs a good cotton wick.
When is Karthigai Deepam in 2026?
Karthigai Deepam falls on 24 November 2026. Check your family calendar, as the lamp-lighting days can vary by a day.