Viv, first I wouldn't repot in a clay pot..Even though citrus soil needs to dry between waterings, it may dry too much..clay absorbs moisture, therefore you'll find yourself watering your plants a lot. I only use clay pots for cactus and succulents.
As for the size, what size pot is it in now? You shouldn't repot more than 2 sizes up..so let's say your plant is in an 8" pot..Transplant in a 10 or 12". Check the rootball..that's the best way to tell what size to pot in. You want enough space to add soil, yet not too big the plant will stay constantly wet.

If you're going to use regular potting mix, you'll need to add soemthing for drainage..I use peat and Perlite. Some ppl use husks. I prefer soils though, but that's up to you.

If you have citrus fertilizer than use that..Miracle Gro will also work..as long as it's for acidic plants.

I use drip irrigation in winter (w/bottles) but it's best to water regularly..w/an occasional shower. If you're going to keep your tree outside, the rain does wonders. I don't know how much rain you get there, but it cleans leaves, and flushes soil to rid salts..Hosing will also help when watering. This is one reason I can't wait until summer..
Keep us posted how you're going to grow your new tree..Toni

Toni, thanks for the info.

I guess I will use a plastic container for my plant, I believe it is in a #5 container.

I don't have a garden, so I will put my plant in the patio and it won't get any rain water. Is it a good idea to use drip irrigation then? Or should I wait till winter?

thanks

The miracid should be fine for your tree--I use it and like it, along with some long-acting granules, occasional fish emulsion, iron chelate/zinc solution and epsom salt.

I think that whether or not you use a clay pot is really up to you (assuming it is unglazed)--clay can wick some moisture out of the soil and contibute to drying it out--and that can be good or bad depending on your climate and how often you want/need to water. It is also heavier which is good if you have a lot of wind knocking things over, or bad if you plan to lug it around. Finally, over time some of the salts that are in your soil, water, and fertilizer can deposit onto the outside of the pot as it leaches through, which some people find unattractive and some don't care about.

How deep your pots are depend on how well your medium holds water--generally, picking a deeper one *may* help with issues of overwatering, a common problem.

You are going to need to water your new tree, and I bet a drip irrigation system would work just fine, but you may want to see how much and how often you need to water before putting it on a timer, and also remember to adjust that for different conditions.

HTH.

I've recently inherited a Dwarf Meyer Lemon from a friend who had no love to give it. Sad little thing, scrawny, few leaves, bone dry, but with several developing fruit. I trimmed the dead wood, gave it a good soaking and some Miracle Grow, and set it on my sunny deck. Beyond that, I have no clue how to resurrect this little plant. Any suggestions on care, insects, pruning, etc.? I have a brown thumb, but I'm willing to try...