Companion planting with flowers

Morning all!

I want to sow lots of companion flowers to sit around my veg, provide some colour and attract beneficial wildlife. I have the seeds and know what they partner up well with but I have a few questions regarding direct sowing vs pot sowing and weed potential!

Im sowing:
Poached Egg Plant,
chamomile,
borage,
calendula,
bergamot,
nasturtium,
marigolds,
Cosmos and
Corn Marigold

Some of these have the potential to become established weeds so was wondering if they could be sown in pots or trays rather than directly? The added bonus here could be the ability to move them around too. I have a lot of these narrow black seed trays which are about 3" wide, 10" long and 3 or 4" deep; would these be suitable for sowing in or do the roots need more space? It's mainly the corn marigolds and poached egg plants im worried about, some of the others obviously will just pull up at the end of the season.

Or if i cut them before the seeds fall will that be enough to prevent any of them becoming a problem?

I dont want to introduce more weeds than Ive managed to eradicate!

All the best folks

I've never had cosmos or bedding marigolds self seed.  Poached egg plants do so prolifically and can be a bit of a pain, but they are easy enough to dig in as green manure when small.   

Borage, nasturtium and calendula all self seed on my plot, but are easy to pull out if they are in the wrong place.

Corn marigold could potentially be one to watch as well.  I've not grown it, but I can see its potential to seed everywhere.

Borage and cosmos would be too restricted in a trough as they are large plants.  The others would need a lot of watering, but in theory you could grow them like that.

I'd personally avoid Poached Egg plants like the plague!

I'd personally avoid Poached Egg plants like the plague!

My neighbour has the stuff running wild in his fruit cage.

In terms of attracting beneficial insects, I'd add coriander and basil (let them flower) plus alyssum to that list. In my experience they all attract a lot of predators and parasites that will help keep the veg crop clean(er).

Nasturtiums are incredibly attractive to early arrivals of black bean aphid and we use them as a sacrificial 'trap crop' in pots so they can be disposed of once the 'good bugs' have moved into the beans later to munch and parasitise the aphids.

Poached egg plants - really good for the beneficial insects esp. hoverflies - I tolerate them when they pop up elsewhere - they're not really going to rob your crops of too many nutrients and I don't find it too arduous-a-task to pull a few up if they're in the wrong place.

I'd always plant into the soil or at east a large pot so watering doesn't become to much hassle.

I always grow marigolds alongside tomotoes to keep the pests aways.  Seems to work.