Art Flower Therapy for Children

We bought flower pots and decorated them by drawing pictures with colourful pens. Then we put soil and planted seeds. A couple of days later, one of the girls said in excitement that some of them started sprouting. Wow. That's amazing. Even though the pots are in the house, I thought it would take many days for sprouting.

Later the evening, I noted that the same ones grew about 1cm taller than that morning. Amazing!!

What are the secrets?