is that a spider mite ? how to kill them all

Just a normal spider, nothing to worry about, unless you have thousands, but they won't harm your plants anyhow. Apart from the webs, this particular spider will do more good than harm. Spider mites are the size of pin pricks, will leave white dots all over the leaves and very obvious fine silky webs completely wrapping the buds. Whatever you do, do not spray the buds with anything, you will be consuming it later, and there is no way to remove the residue from spraying 100% effectively, so if you do spray, you will be smoking buds with residual and potentially harmful chemicals too. Neem is also not an entirely safe product either. In fact, in my country it is illegal to use neem on any product intended for human consumption. Hope this helps,...... Organoman.

Not spider mites thankfully. Looks like a normal spider. I would get rid of it but it probably wouldn't do much harm leaving it in there. If you have a pest problem the spider might actually help lower the problem.

That looks like an American brown spider. It's harmless to you and plant. May help rid of unwanted insects.

Spidermites leave little white dots all over your leaves.

Just a spider. It will eat any spidermites so don't kill him. Cheers