I also got a Lula avocado and some mexican limes grown from seeds
what do I also use to cover them
33 is the low forcasted

I am no expert by any means and am learning by trial and error, but I cover my citrus if frost is expected or if it dips below 30. However, it also depends on what variety of citrus you have. Limes are the least cold-hardy, so I would probably cover them if 33 is in the forecast. I believe that avocados are generally less cold-hardy than citrus. Have you been having cold nights recently?

I just use old blankets and sheets, but they have frost cloths and such at hardware stores. If possible, build a frame out of PVC or wood so the blanket is not right on top of the tree...my trees are all against my house or a fence, so I lean 2x4s against the structure and hang the blanket on that.

Living in northern California and having lots of citrus outside I have had a fair amount of experience with this. We commonly have freezing temperatures, but it only rarely gets below 28° or so. I have a Bearss lime, Eureka lemon, Meyer lemon and various mandarins and oranges outside unprotected. I virtually never provide any protection to these tress, although the lime and lemons are directly next to my house so they get some protection that way. The lime typically looses many of its leaves over the winter, but it always recovers quickly in the spring. The other citrus have absolutely no problem with these temperatures. I would add that local microclimates in borderline growing regions for citrus are VERY important. Even on a small property there will be significant differences in temperatures depending upon elevation, proximity to the house, and tree cover. I hope this helps.

-Brett

Key limes (Mexican limes) are about as cold sensitive as citrus gets in my experience. If there's a chance of frost I'd cover them unless you don't mind losing leaves.

.....Alan.

Well I didn't cover any of my trees. My key lime shows no damage nor the Lula or mexicola or peach tree but
my poor mango got slot of damaged leaves most of them are pale along with the stick it's growing on but the main trunk looks good
should I prune it back and see if new growth shoots or what do you think

I wouldn't prune anything before about midspring. The damage may not be as extensive as it first appears and you wouldn't want to encourage new growth right now.

.....Alan.