L have grown huge gardens for 60 years. As a child that's was our main source of food.i have grown a few vegetables on my balcony the last few years. This year, from purchased bags of soil, my Carrots and Beets have big leaves but no substantial roots. The carrot tops are over a foot high and the thin little carrots are a couple of inches long. They should be thicker and at least 4 inches long. The beets are the size of a matchstick. I have never seen this before.
Are you growing them in the bag or in a container? You may need a larger container for good root growth. This article is about raised beds, but it shows the depth vegetables need.
Also, are your veggies getting full sun on the patio? That can be an issue. Here is more:
https://www.gardeningknowhow.com/edible/vegetables/vgen/raised-bed-soil-depth.htm
https://www.gardeningknowhow.com/special/containers/growing-vegetables-in-buckets.htm
I am beginner in farming. I want to know more on new plants.
There are several choices for you, like tomatoes and beans, among many others! Here is an article that will help you and suggest other vegetables that would be suitable:
https://www.gardeningknowhow.com/edible/vegetables/vgen/vegetable-gardening-for-beginners.htm
I'm living in South Africa. I have big tall Oak trees and very little sun. Please help. Kindest Regards.
These articles should help:
https://www.gardeningknowhow.com/edible/vegetables/vgen/shade-vegetables.htm
https://www.gardeningknowhow.com/special/shade/ground-covers-for-shade.htm
I want to set my raised bed in my back garden now
Sure! This article will have some information on the subject that you will find useful:
https://www.gardeningknowhow.com/special/children/a-three-sisters-garden.htm