No way to tell without comparing the two soils, watering and fertilization schedule, amount of sun, type of plant, etc, etc.

Walls do help reflect heat and light, which can be good for tomatoes. So while there are a lot of factors there is a good chance the wall is helping.

I grew tomatoes about 25 yrs for the first time, they were hugh full of green foliage but hardly any tomatoes :(

I would look to your soil ammendments first. I added a bunch of goat manure to one bed, and the tomatoes, with the exact same planting dates and care, are about 3-4x the size of my plants in a different bed that did not get as generously ammended this year.

dad bought plants last year as well as this year. different growers? did not ask him about that. did not add anything to soil. no compost or fortifiers. wimpy tomato plants last year but lots of tomatoes. i am hoping to get something to eat this year after netting my garden. deer have snarfed everything the last 2 yrs. not a single tomato, or pepper. even at my habanaro's.