I have just been reading that Nasturtium,s flower better when planted in poor soil.I used a bagged John Innes compost, planting the seeds them late Spring (due to the awful weather we had),there are plenty leaves but when can I expect them to flower.This is the third year of using the seeds which I collect after flowering,is there a time scale on seeds being re-used.
Also I read ,one should dead head (which I do with other flowers)..but if I do this,there will be no seeds.Am I correct in thinking this.
They flower better in poor soil, but grow better in good soil and produce fewer flowers.
To continue flowering you need to 'deadhead' them. Yes, if you deadhead them then seeds will not form. You've got to strike a happy balance.
Basically an annual plants sole purpose in life is to produce seeds. Once its done that, it will die happy.
As an aside the leaves and flowers can be added to salads.