As a general rule, chilli seeds need a temperature of 23-30 degrees Celsius (73-86 degrees Fahrenheit) to germinate. Place your seeds in a spot with consistent warmth (e.g. on a heated mat) for a period of 2-5 days, until they swell or sprout. If you don’t have a propagator, use polythene to cover your seed trays. Germination usually takes 7-10 days, after which you can move your seedlings to a warm, sunny windowsill or a heated greenhouse. Keep the compost evenly moist but take care not to let it get soaking wet. Your chilli seeds need warmth, 80-85F, to begin the germination (sprouting) process. Light is not critical at this stage, but bottom heat or a warm location is. … Just as soon as the seeds have begun to sprout and show above the soil line, the baby seedlings require bright light.