Cosmos advice requested

That's fine, but you are limiting yourself as to what you can grow. I grow lots of HHA's and they need to start inside, but they produce some of the most wonderful flowers: Dahlias, Cannas and Ricin being a few examples.

 

With cosmos I find that after they germinate I wait until the first true leaves are growing well .I then prick out into small pots .soon as they are four inch I nip out the growing tip (just the middle bit )
I then continue to grow on in this pot and repeatedly nip out the centre grow point.the plant will start branching out and forming like a bush.I usually leave until towards the end of June to plant out.
Don't put them too close when planting in the final place.. They will carry on branching out .mine spread a good 24 inch and must have h had around 200 flowers .Will find photo for