I'm getting a bit confused about different types of fertilisers. I have liquid Growmore which is what I have always used before (I have garden compost, 6X and horse manure as well). Should I really be a little more serious and invest in tomato fertiliser etc ?? I am growing tomatoes, chillies, peppers, courgettes, onions, dwarf beans, lettuce, carrots, parsnips, spinach, physalis, strawberries ...... this year ??? What should I use on what ?? What is really essential ??