Composted vs Non-composted Plant

Non-composted plantI planted this soon to be avocado tree 2 months ago. Our backyard soil is basically gravel far from the ideal for growing anything. Somehow, we have managed to grow some plants but the problem is the plants easily get sick and eventually die. The best we've grown so far is one lonesome papaya tree but it eventually died when it reached 5 feet. It gave us a couple of papaya fruits. But that's it. I also tried planting my herbs (three types of basil and oregano. I also included sweet potatoes,essentially for the tops alone. But no go.

Composted plant And then there was this corner in our backyard where grass and weeds were growing like anything. I dedided to make a compost out of the mangoes that fell from our neighbor's tree. There were so many of them I could have made several liters of mango jam. Problem is it was the indian mango variety. The compost was actually just a small pit where, I threw all our veggie and fruit scrapings from avocado, kalamansi, lychee, atis, etc.

Several months passed. We were surprised to see 3 avocado seedlings growing. We decided to remove one from its original home to another place in the backyard where there was better sunshine. The two remaining stayed where they were. At this point the lone seedling was about 6 inches. The two others were just about 3 inches. And because it was the wet season over here, rains came pouring, alternating with brief sunshiny days. And what have I got after 3 months? Lo and behold. The composted seedling had grown to about 1 1/2 feet. While the much older seedling grew to about 6 inches.