Why do you think you need mulch in a 20 inch pot?

Soil cooling and root protection, maybe some moisture retention.

I'm interested in this as well, I just put topsoil in mine!

Personally. I would put a thin layer or bark to keep the top couple of inches from drying where a lot of your fine roots are , but not to much so as not to encourage your roots to grow towards the surface...

It would be perfect if the roots grew well down into the pot and not send up them up towards the top.

Mike

Eur, the topic is about a thin layer of mulch (straw, pine bark, etc.) on TOP of the potting soil. Frankly, I don't think that anyone here will encourage the use of top soil i a container. No matter how great it is, it will turn into something else after being confined in the container for awhile.

Oxboy, I don't think that most people apply mulch to their containers. Outside plantings, yes. But as my pal Mike suggests, a very thin layer of pine BARK chips wouldn't be harmful. Avoid stones of any kind....not any cooling with those.

Be sure that the bark is not piled up against the trunk! If it floats to the trunk after a thorough watering, readjust it.

(That little rule always needs to be followed but especially so with citrus.)

Yes, about a 1" layer of bark mulch is important for container citrus in warm/hot climates. All my citrus have bark mulch for sure as it is just way too warm and dry not to have this. Plus, my container potting medium has more fines in it than the regular 511 or gritty mix, again, since we get zero rainfall, and my container citrus have to rely on me watering them :-) If I went with a straight 511 mix, I'd be watering 2 to 3 times a day in the summer! Also, I always plant my citrus up (like meyermike does if you look at his photos of his container citrus), because I can't always guarantee that my bark won't be up against the trunk. Rhizo, it is so dry here, there is NO worry of a container citrus getting gummosis. In the ground, yes. But in a pot, you'd have to have it planted in clay and water it excessively to worry about any fungal attacks on the trunk :-) We're more worried about water stress that excess water issues here with our container citrus. Which reminds me, I need to get out and water them today!

Patty S.

Excellent information, Patty.