Aubergines like a long hot growing season, and so need to be in a green house or polytunnel. They also need a warm place to germinate so I like to start them on a window sill in the house or in a propagator. The seedlings will be killed by frost and will not thrive when nights are cold. So unless you have a heated greenhouse or conservatory, restrain yourself from sowing them till February.
Prick out the seedlings into 10cm pots when they have a couple of real leaves and keep them cosy until they are planted out in their final positions in April or May. Here, we dig a trench in the polytunnel in spring and fill it up with well-rotted FYM. The trench is covered up with soil again and then with ground cover. The ground cover has holes 60cm apart and the plants are planted through these holes.
Pinch out the tip of the plant when it is about 30cm high to stop them getting too tall and falling over. Cut the fruit when they are well formed and before they have lost their shine.
Saving the Seeds
To save the seeds the fruit must be left until they are really ripe. The skin changes from shiny black to a dull brown color, then just before it rots it can be harvested. There is no easy way to get the seeds out. We grate the fruit into a container, cover the pulp with water and leave in a warm place for a couple of days. Whisk the mix a few times when you are passing and most of the seeds will fall to the bottom, then the water and pulp can be poured off leaving the seeds in the container. They will keep for several years when dried and stored in a cool place.