Will 20 year old seeds still germinate? The packets have never been opened. They are Tomato, Aubergine, Sweet Corn, Courgette, Capsicum, Sweet Pea, Nigella, Kochia, and A;yssum.
I would give it a go out of sheer interest, but dont be too disappointed if nothing happens, it is after all a long time, but then you could be lucky with a few.
The best way to test germination is to scatter a little of the seed onto damp kitchen paper and keep moist. Most seeds should germinate under those conditions and then it would be possible to see if it was worth wasting compost on sowing conventionally.
Last year a TV programme about Kew Gardens told of them planting some over 100 yrs old seeds collected in South Africa. Some of them grew, they were really pleased.