A new way to check the growth of plants?

This happened when i was doing my schooling...
We lived in a rented house. It was a small house and was surrounded by a small area. As it was newly built, the soil was covered by cement, stone and other building material. When we first went there, my mom, me and my sister dint like the place, as we hardly find any greens there. So we three worked very hard and cleared all building materials and manured the soil and planted lots of small flowering plants. Within 2 months, the place became very beautiful and cool, due to plants. Our house owner appreciated our work. He was very happy, as he too could see some greens and colors around.

After few weeks, we started noticing that a few of our plants were missing daily. One day we caught the thief too. It was the house owner's grandson. He was 5 or 6 yrs old by then. One day, we saw him, plucking the plant and running. Another day when we asked him, he replied, he too wants to grow plants. So we gave him some plants to grow. 2 weeks went and the plant died. We gave some more plants and within a week, it died too. We asked him to water the plant properly and place it in a sunny place, gave him the plants again. It was placed in a sunny, airy place and watered properly. We started to notice the plants and him. The next day we saw that. He was examining the roots of the plant. He shook the plant and took off all the soil from the root and poured some water in the root and then he planted it again. When we caught him, he told, "roots valaruthannu parkurein?" The silly boy was plucking the whole plant from the sand daily and examining the roots, to know its growth. ha ha ha.