Pepper Plants 2
Six weeks ago I transplanted my potted peppers in very hard ground. I dug holes about 1.5 feet deep and 16 inches diameter and filled them with new gardening soil. Although they have filled in a little, their stature has not perceivably changed.
Since peppers can grow up to approximately 18 feet, they are also a deep rooted plant. Like most plants, they will take any opportunity to become root bound at the sake of growth of the rest of the plant.
So my Question: Is there any formula for figuring out the time it will take for the roots to fill their soil environments by volume and depth?
I know of no formula to do what you're asking. There are so many factors to take into consideration I would say it would be extremely difficult. The type of soil, the amount of moisture, the nutrient status of the soil, temperature, etc would all have some effect on how quickly plant roots become established. In KY, we do not recommend 'good potting soil' as a backfill, especially in hard, clayey ground. The native soil can become a bowl and hold water such that roots can potentially drown (depending on rain and irrigation).
I don't know where you're located, but in KY some peppers can get rather tall but usually never approach 18 feet. More like 5 to 6 feet is as big as I've seen them. Regardless, plants need green leaves functioning well to produce a good root system but they also need a well-drained soil so that roots can penetrate it easily. They also need the right nutrients either supplied in the soil or through fertilization. They also need sun since sunlight drives the whole machine.
I hope this helps even though I know I couldn't answer your question. Please let me know if you need more information. I will try to help.