Why and how does the location affect plant growth?
This is a wide ranging question. Many plants love the sun and will only do well with good full exposure. Some will do okay but never reach their full potential in partial sun and will be stagnant or die in shade. Other plants prefer shade and thrive well in it, exposing them to too much sun will burn the foliage and either stunt their growth or kill them. Rosebushes love the sun and need alot of it to truly reach their potential. Hosta plants love the shade and do best in it. These are just two cases of full sun and shade plants. There are many perennials that do well in partial sun/shade. Here is a link to a great site on Plant Growth that you may find of interest: http://www.phschool.com/science/biology_place/biocoach/plants/intro.html
My question is related to the neem oil spray. Where about can I buy this product from?
I would like to know more about basic plant growth.
I recommend that you go to the Gardening Know How website and do a search on this topic. There are alot of great articles there on various plants and tips on how to grow the ones of interest best. When it comes to water and plant growth there is a wide ranging difference on how much water a given plant will need. Give some plants too much water and they will die as their need is low, give some plants too little water and they will die as their need is very high. Watering plants in containers can be tricky as too much water will cause root rot or actually drown the plant thus killing it. Here is a link to the site: https://www.gardeningknowhow.com/ . Enjoy the fine reading there!
What are the problems encountered in bio-intensive gardening?
Since this type of gardening focuses a lot on soil building, it can be realtively extensive for those without the time that may be involved. However, this is a great way to improve the soil quality and produce healthy plants organically. To learn more about biointensive gardening, this article should help: https://www.gardeningknowhow.com/special/organic/biointensive-planting-method.htm
How high do the plants grow? I am a beginner.
It really depends on the plants that you choose to grow. Carrots and radishes stay pretty low to the ground, but tomatoes can easily get 6 feet tall. If you are new to vegetable gardening, I suggest that you take a look at our vegetable gardening category: https://www.gardeningknowhow.com/edible/vegetables/vgen/vegetable-gardening-advice.htm
We have many articles on growing all kinds of vegetables.
I am doing a little research and I seem to remember reading about how plants (vegetables/fruits) have naturally occuring phyto-chemicals in them that also increase the nutritive value of these plants. Of course, they would have to be grown organically. What I am looking for is some information on whether this is true. Can anyone help me with this? I have been searching the Internet and can't find anything other than the basic fact that organic is better simply because of the non-use of toxins.
This article might help:
What is the definition of annual?
Annual means one year. For example, annual plants grow and survive only one year, whereas perennials come back every year. Annual pruning means the pruning maintenance is performed once yearly. Hope this helps.