feeding tomatoes

Hi All,

I've been reading differing suggestions on how best to fertilise tomatoes over their growing season. As a result I am a little confused. There seems to be consensus on not feeding them until they flower and even not before they set fruit. But after that it varies. I gather they need good amounts phosphorus and potash, but not much nitrogen.

Can anyone suggest a good regime for me? Organic preferred. I've got a worm farm, some compost going (prob won't be ready though), liquid potash, seasol etc.

Thanks
Ben