Day 16: since yesterday, the plant has grown 1.9 cm!
Day 20: showered the plant with a mixture of distilled water, neem oil and soft potassium soap.
The plant seemed to be growing well until the twenty-first day, when there was a sudden yellowing of the leaves: I watered with 4,5 l of water, we will see how she reacts.
@CanuckTaughtMe,
thanks for the vote of confidence, but I don't think I'm a good example: it's the first time I've reached the fourth week of cultivation and I'm making a lot of mistakes...