I would just give it time. Unless its a desease or something your Health Kick will eventually color up. Dr. Wyches Yellow and Hungarian Oval were yellow for a the longest time for me and they just finally started to color up. Be patient.

Damon

bakaroni - this one looks a little nutrient deprived. It will likely recover on its own once it gets over transplant shock but I was curious as to what you are feeding with and how often? Container plants need more food and need it more often than do in-ground so, if it were me, I'd feed this baby a diluted dose of a well-balanced liquid fertilizer. JMO

Dave

I bought it only last week and transplanted it then. It was already a bit yellow, but it turned yellower in a day or two. I used an organic (4-7-3) fertilizer and some epsom salt in a potting mix medium. Should I add a bit of manure or compost?

Interestingly, all the other tomatoes that were planted in containers got the same treatment.