I think this probably is overwatering. Is the whole of the bottom yellow?
If not, could you remove the infected tissue with a sharp, clean knife?
I think it is OK to water every couple of week at this time of year but were you doing that during the winter months? I would hardly water a cactus at all Nov, Dec, Jan and Feb and then slowly increase as the weather warms up. Check the compost, is it free draining with plenty of grit? are the roots of the Cactus sitting in a pool of water; you want to avoid that at all times of year. Whilst watering is important it is also important to get rid of any unwanted water the plant has not soaked up.Statistics: Posted by gardening_guru — 23 Jul 2008 20:04
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