Nothing's come up yet. Here's why.

You sowed a fortnight ago. The tray is sitting there doing nothing, and you're starting to wonder whether the seeds were duds.

Nine times out of ten they aren't. Chilli seeds are slower and fussier than almost anything else you'll sow, and the usual culprit is temperature. Here's how to work out what's going on before you give up on the batch.

First, how long is actually normal

This is where most worry comes from. People expect chilli to behave like tomato or basil. It doesn't.

• Capsicum annuum (jalapeño, cayenne, most of the milder types): usually 7 to 14 days at the right temperature.
• Capsicum chinense (habanero, ghost, scorpion, most superhots): commonly 14 to 21 days, and 4 weeks is not unusual.
• Cold soil, any species: add another one to three weeks, if they come up at all.

So if you're at day 10 with a tray of superhots, you're not behind. You're on schedule. Give it another fortnight before you touch anything.

Cause 1: the soil is colder than you think

This is the big one, and it's behind most winter germination failures in New Zealand.

Chilli seed wants a soil temperature around 25 to 28°C, with the chinense types at the warmer end of that. Air temperature is not the same thing. A room that feels comfortable at 20°C will have a seed tray sitting several degrees cooler, and a tray on a windowsill can drop close to single figures overnight in July.

What matters is not the daytime peak. It's the overnight low. Seeds that warm up nicely at 2pm and then chill to 12°C by midnight will either stall or rot.

What to do: get the tray onto a heat mat, or into a hot water cupboard, or on top of the fridge. If you can, put a cheap probe thermometer into the mix and actually read it. Guessing is how people lose a whole sowing.

Cause 2: too much water

Overwatering runs a close second. Waterlogged mix pushes the air out of the soil, and seeds need oxygen to germinate. Sit them in a saturated tray and they'll rot rather than sprout.

It also sets you up for damping off, the fungal problem that fells seedlings at soil level just as they get going. It thrives in wet, compacted, poorly drained mix with not enough light or air movement.

What to do: aim for damp, not wet. Think of a wrung out cloth. Use a free draining seed mix, make sure the tray has drainage holes, and empty any saucer after watering. Cover the tray to hold humidity if you like, but lift the cover daily for a bit of air.

Cause 3: sown too deep

Chilli seed is small and doesn't have much energy in reserve. Bury it at 20mm and it may germinate but exhaust itself before it reaches the surface.

What to do: about 5 to 6mm deep. A light scatter of mix over the top is plenty. Firm it gently, don't compact it.

Cause 4: it dried out at the wrong moment

Once a seed takes up water and starts the germination process, drying out will kill it. This one is sneaky because the tray can look fine on the surface while the seed sits in dry mix underneath, and a heat mat dries a tray faster than you'd expect.

What to do: check daily once you've got heat under it. Consistent moisture matters more than a lot of moisture.

Cause 5: the seed is old, or was stored badly

Chilli seed keeps reasonably well. Two to three years in a cool, dry, dark place is fine, and well stored seed can go a good deal longer than that. What ruins it is warmth and humidity, so seed left in a hot car, a sunny shelf or a steamy kitchen drawer will fade fast.

What to do: if the seed is several seasons old and stored loose somewhere warm, sow more than you need and expect a lower strike rate. Store the rest in a sealed container somewhere cool and dark.

Cause 6: you're checking too often

Tempting, but digging around to see whether anything is happening disturbs the seed and dries the mix. Leave it alone. Chilli seed does not need light to germinate, only warmth and moisture, so there's nothing to check on until a green loop appears.

Still nothing after four weeks?

At that point it's fair to call it. Before you resow, work through this:

1. Do you know the soil temperature, or are you assuming it?
2. Was the mix consistently damp the whole time, or did it dry out or sit soggy?
3. How deep did you actually sow?
4. How old is the seed, and where has it been living?

Fix whichever one you can't answer confidently, then resow. Most people get a full tray on the second attempt purely from adding bottom heat.

When to get in touch

If you've had heat, steady moisture, shallow sowing and fresh seed, and still nothing after four to five weeks, something may genuinely be wrong with the batch. Send us an email and tell us what you sowed, when, what the soil temperature was and what mix you used. We'd rather sort it out than have you quietly write us off.

We test and pack our own seed, and we'd genuinely like to know if a line isn't performing.