In what part of Oz land do you live? Can you put your Meyer in the ground? They are much easier to deal with when planted in the ground. Pictures would help, of course. If it is in a pot now; and you are going to plant it in the ground, you only have to dig a hole a little bigger than the pot; carefully take the tree out of the pot (for me I always choose to destroy the pot to preserve the rootball) and put it in the hole. Back fill with the dirt from the hole , water it in well and wait. When it begins to make new growth you can begin a regular fertilizer regime; but not before; the absence of nutrients encourages the roots to grow seeking food and water; and with citrus, first the roots grow and then leaves and branches.

Thank you both for the advice! I have mid to high 40's in my area the next week or so, so I'm leaving it out for now. I am not as concerned about transitioning light levels now as its literally going 3 feet inside of its exact spot that its in. but I am concerned about pests. This is my first year with fruit trees and I've already lost my apples and fig to what I'm guessing was spider mites. One week they were fine and healthy then they started drooping and turning brown. I didn't see an pests so I assumed it was a watering issue but once it was too late (they were all brown/shriveled) I noticed fine webbing that seemed to be on the remains of the leaves. I assume they are beyond salvage but I cant bring myself to toss them out. I plan on washing my pot of the lemon tree and spraying it but I have no idea what to spray with or how much. I've sifted through the forums and seen HO and neem mentioned as well as insecticidal soap but I'm not sure what brand to get or how to treat. Any suggestions or favorites?

I am growing a Meyers lemon (along with other citrus, mostly Satsumas) in ground on the 8b/9a line in Louisiana, a few months ago we had our coldest night in the last 50-75 years, with the low hitting about 13F / 14F two nights in a row and all my in ground citrus survived, though all had at least some leaf loss and die back, even though they were covered and had 200-250 watts of heat lamps / C7 incandescent christmas lights on each tree. Surprisingly the Meyers was not the worst hit, that honor went to a 3rd year in ground Satsuma which was killed back to within a few inches of the graft union. The Meyers only lost about half its leaves, and had slight dieback (3-6 inches on the smaller limbs), it was also on its 3rd year in ground and is about 5 ft tall.

Well, congrats on that!! I know how that feels. I found tons on my Kishu manderine tree only because they turned orange. lol I would of never noticed if they had stayed green By the way. eventually the roots will compete and one will strangle the other, For now the annuals are probably helping you to allow the mix dry out quickly.