The seeds that were sown in the pot have come through, bravo! However, the more difficult bit still needs to be done. The young seedlings need to be pampered if they are going to grow big enough to be planted out in the garden.
Lots of light !
When the seeds germinate, they form cotyledons, which act as provisional leaves. As soon as the cotyledons appear, the plant will need a sufficient amount of light.
Move the pots closer to a west facing window if you are growing your seedlings inside. Avoid them having full sun for the moment. If the seedlings' stems start to get leggy then it means they are looking for light so you must give them more.
The real leaves will quickly form between the cotyledons and the seedlings will start to grow a little bigger.
They can soon start to crowd each other out if they have been sown too closely. In this case, you will need to thin them out by gently removing about half of the seedling, more if necessary. It is important that the young plants do not touch one another.
Water them gently but regularly without soaking the soil. Moisten them in the middle of the day and always from underneath. Also, air the plants for a few hours a day in a spot sheltered from strong currents of air.
In good weather put the seedlings outside for a while. If you permanently leave them in a confined space, they will suffer from the fate of seedlings, that is to say that they will all of a sudden die. Delicate seedlings like those of basil are particularly susceptible. You can reduce the risk of this happening by dusting the surface of the pot with charcoal powder at the time of sowing.
Pricking out
When the seedlings are big enough to be handled, for example when the third proper leaf has appeared (do not count the cotyledons) prick them out into individual pots or a large recipient. Grasp them gently and lift them out with a small flat stick taking care not to damage the roots.
Replant them so that they have at least 7cm of space all around them. Put them into a hole made by a stick and carefully push the soil around the roots so they are firm. This is a delicate operation and can damage the young plants when they are handled. The compost that you use does not need to be mixed with sand. The pricked out seedlings need to be kept in the open air and not in an enclosed container. They need less heat now than when they germinated.
Leave them to grow like this until it is time to plant them in the ground, for example after the last frosts of the spring. Certain seedlings grow very quickly and are pricked out directly into the ground rather than a pot. If the temperature is favourable and the seedling is at least 3cm high, then you can replant them directly into the ground. Watch out for slug attacks!