Well, first off, let's clear out the grass carefully from under the tree. Secondly, your soil looks pretty dense, are you on clay? If so, be careful not to over water. Citrus do better when planted on raised mounds if you have clay soil. Lastly, I would identify what is eating your citrus leaves. Go out in the early morning, or later evening, as that's when bugs tend to come out to forage. I can't tell for sure, since the photo isn't close enough, but it could be snails or slugs eating your leaves. So, ID the pest and treat, accordingly. Fertilize 3 to 4 times a year, and not too late in the season, as you do not want tender new flush exposed to cold temps. Protect your tree from temps that threaten to fall below 32 degrees. Fruit drop is not at all unusual for a tree trying to re-establish itself. Give it a year to recover well.

Patty S.

What time of the year? What's best to fertilize with?

you can use most fertilizers that contain micronutrients.

i would suspect deer are munching on the leaves.

What would be a good watering schedule?

Water when the tree needs it. Check the soil 18 to 24 inches down. If it is still moist, don't water. You'll get to know your soil's moisture retention during different times of the year. You may need to water more during hot dry times, less during cooler rainier times.

Patty S.