Just got more information from my friend. The lemon had been in a container for several years during which time she got a few lemons.

It is watered via a drip system which goes on 3 times a week for 20 minutes. During the winter she runs it if no rain for 4 days, she keeps it on from late winter through fall.

She fertilized with Citrus/Avocado food in late February and I told her to fertilize again in May (opps), and July.

It gets half day sun, in the middle of the day.

When she planted it 4 years ago she dug up an area 3' by 3' and amended the clay soil with compost.

As she just said, it's interesting it is a full tree yet without fruit. I told her my friends at GardenWeb will have some answers.

Thanks for your help!!

Ginny

it was said "drip system which goes on 3 times a week for 20 minutes."

your friend is lucky the tree is still alive. Must run the system long enough to moisten the entire rootzone.

When I lived in California (Long Beach), I ran the system for 2 hours every 5 or so days.

With drip and/or soakers, one must experiment to determine how long it takes for the water to go where it's needed.

how's the weather in your area? i know CA has many different weather/climate.

We live in San Jose. We have several hot days (90+) each year but are mostly in the 80's during the summer. We have mild winters and last year had a ton of rain.

Because she lives in a small condo, her little garden is surrounded by cement on two sides and a cement patio so I'd think it gets some reflected heat.

Ginny

citrus can tolerate hot temps, here in houston june july and august are usually in the mid 90's up to 100'F

could be not enough water to stimulate it into flowering. it may just be getting enough to survive. generally we have a dry/winter season. then a wet/spring/autumn season that encourages flowering.

some growers will not water during the summer to the point where the trees are stressed, starting to get dehydrated, then flood the fields to create the "wet season" which forces a 2nd fruit production. your friend could try that, not water for a few weeks, then soak it down really well.