I have been growing tomatoes in pots at North Sydney for the last 10 years. Each year is more problematic and depressing than the previous even though I sterilise pots and use new potting mix each year. Plants start off very healthy then about the time that fruit set, the plants start yellowing from the bottom and within a few weeks they are history. This year was interesting in that I placed the pots on a second story balcony well away from previous plantings on the assumption that whatever was killing the plants near the ground may not exist on the balcony. I planted in September, great plants until mid November when they did the same thing - started yellowing from the bottom up and ended up basically dead after a few weeks. I took one of the plants (Mighty Red) which was dead except for one small leaf about 10mm above ground level. I cut the plant off completely immediately above this leaf and planted it in a new garden bed we have recently created in the area where we had previously used pots. For a couple of weeks nothing happened then the plant started growing and now in mid March we have just picked 3 large tomatoes off a very healthy (large) plant with another 15 or so tomatoes still on the plant. I still don't know what causes the problem but the experiment with this 'Lazarus' plant is nothing if not interesting.

- Ian