Self-seeders

I sowed and grew four long rows of summer flowers at the allotment last year (mainly annuals) which gave a tremendous show of colour to the area. I haven't touched that area since and I am hopefull of an equally colourful show this year from the self seeders? Once the weather dries up a bit I will chop down the dead foliage and clear the two paths that are within the area and hopefully have another self seeded show of flowers this year. One problem I can forsee is weeding the area?, though we will cross that bridge when I get to it.
I may even buy another couple of packets/ boxes of seedss to 'beef up' the area as they were only a quid a box or packet from Poundland if I remmeber rightly?