Why has my pansy plant suddenly collapsed and died?
Although relatively trouble-free, pansies are still susceptible to diseases like root rot, powdery mildew, leaf spot, cucumber mosaic virus (which is spread by aphids) and stem rot (aka pansy sickness). It sounds like the last one is your problem; stem rot is a soil-borne fungus sometimes associated with unsterilised animal manure and it can cause pansies to collapse without warning. There are sprays available for the soil, but your best bet may be to simply dispose of the diseased plants.
Could you tell me more about the rat-tailed radish?
This unusual vegetable is related to regular radishes, but instead of eating the root, you wait for the edible seedpods above ground (apparently the seedpods of ordinary radishes are also edible if you get desperate). Rat-tailed radish seedpods are long, twisted and crunchy, taste like radish and can be used in stir-fries as well as salads. Seeds are available from specialty seed suppliers and you need to allow 20cm between plants - but wait until spring before planting.
If you have a gardening question, email Glenys at glenyswoollard@clear.net.nz