A. Meyer lemon, not a true lemon, is usually harvested in December or possibly as late as early January. But do not harvest it later than this. Harvesting time is your signal for pruning. Waiting longer than this can possibly remove fruit during that growing season.
|Meyer lemon grown in protected culture in Afghanistan.|
Prune immediately after harvest. Do not delay harvesting the fruit or this can confuse the tree about when to flower again and may affect the quality of the fruit.
It is strange your Meyer lemons are ripening now. Fruit can take nearly 11 months to mature. Harvest the fruit when sugar in the fruit reaches a minimum of 10 Brix. Brix is measured with a refractometer. It’s handier to taste the fruit and see if it’s ready. When it is sweet, harvest it.
Citrus is not pruned much, only to remove crossed or broken branches. You could remove a few limbs too close together which would allow more light inside the tree canopy. Probably removing 3 or 4 limbs would be enough.
|Citrus response to pruning cuts|
Make sure the pruning saw or loppers has been sanitized and sharpened before pruning. Do not leave any stubs unless you want regrowth from them.