Grass seeds question

[elhuerto]

I want to plant a few grasses in a border next to the pond on the allotment. I have a selection of seeds from Mr Fothergill's, with sowing instructions but I have a doubt. It says to finally plant them out at 30cm apart but if I wanted clumps, should they be planted together  or they will finally spread out enough do you think? As you can see, never planted grass seeds before except for an attempted lawn  ::)

These are the types by the way

Lamarckia aurea
Melica ciliata
Sataria macrocheata

[elhuerto]

[daitheplant]

They should form clumps on their own over 2 or 3 years.

[elhuerto]

Thanks, I'm a bit concerned they're going to look like weeds til they get any substance.

[goodlife]

I haven't grown those particular grasses from seeds but those that I have did clump up surprisingly quickly..
But after pricking out the seedlings I would still grown them on in pots before planting them in ground...they always grow that bit quicker when in pots. ;)