Can I plant neem in a pot?
In a word, yes. Seeds can be planted about an inch deep in potting soil in a large pot. Use a balanced fertilizer monthly once sprouted, which can take anywhere from a few days to a week or so and water only after the soil becomes dry. Also, keep the neem plant in a warm area that receives plenty of sunlight. You will need to prune regularly to keep the plant under control, cutting limbs off as close to the tree as possible. Pruning is performed in early spring and late summer.
My sweet neem suffered fungus and insect problems in summer. What can I do? Basil also sufferd from pest and there's a problem with dried barley.
Neem oil is good to use for controlling both insect pests and fungal problems. Here is more information: https://www.gardeningknowhow.com/problems/pests/neem-oil-uses.htm
At the corner of my house, I have 1 big neem tree, which is 8 years old, as this year due to heavy wind and rainfall the position of the tree is slant. I want to save this tree, so please give me guidance on how to make this tree straight.
Since you're asking this question on the houseplant forum, I'll assume your neem tree is potted. A leaning tree is not a life threatening condition, but I can understand why you want to straighten it. It's not difficult - stand the tree up straight in the pot, and work soil around it and under it, then water it well to settle the soil around the roots, and add some more soil if needed. You can put a couple of stakes into the pot, and tie the tree to them, to help it continue to stand straight. https://www.gardeningknowhow.com/ornamental/trees/tgen/straighten-tree.htm
winter temperatures typically are around 40F. Can need tree be protected with a tarp with the temperature dips below freezing
I am unfamiliar with a Need Tree. I can't find any reference to it in any literature, either.
If you mean NEEM Tree, then you may need to grow this in container. They are not hardy, even with protection, in your area.
Here is an article that will explain the care that they require:
Indeed, I meant Neem Tree... Didn't realize, I mistyped the word. Thanks for the tip.
Hi, I live in Winters, CA and am considering planting a neem tree in my backyard, but am worried about the roots damaging my house. What is recommendation?
This article may be helpful:
Here's our info on how to grow one: https://www.gardeningknowhow.com/ornamental/trees/neem-tree/neem-tree-information.htm
Can a greenhouse support it during winter ?
Neem trees can grow up to 100 feet tall with a canopy spread of 50 feet. So a greenhouse could only support the fast-growing tree for a short time. Plus, they will not tolerate extended cold temperatures. Here is more information about the neem tree: