Growing from seed means you can choose from a far wider selection of annuals, biennial and perennial plants than those found in your local garden centre. It is also very fulfilling and cheaper so you can grow more plants of the same variety; this is the best way of ensuring repetition and colour in your borders.
Growing seeds indoors allows more control then sowing outside and gives you a higher success rate in raising healthy seedlings.
I like to use 7cm black square plastic pots as you only want to grow a few seeds at once rather than sowing the whole packet of seeds in a tray: when they all come up at once you will not want that many and end up discarding them.
First make sure you use fresh compost and that all your pots have been washed (a disinfectant such as Jeyes fluid is perfect).
The growing medium I use for seeds is: 70% peat free/coir to 30% perlite (this prevents compaction and improves aeration/drainage).
Fill your pot with the compost to 1cm below the top of the pot making sure to firm down the compost, it is important the soil is level. Then put your seeds on top and finally cover with 1cm of vermiculite. A general rule is smaller seeds eg: Nicotiana (tobacco seeds) does not need covering with vermiculite. Always label your seeds with the name and planting date.
Check daily and remove condensation from the lid of the propagator.
As soon as your seeds germinate take them out of the propagator and move to a windowsill or greenhouse shelf out of direct sunlight.
Again, I plant up in 7cm pots. The growing medium I use for potting on is: 70% peat free/coir to 30% vermiculite with some added slow release fertilizer pellets.
Just keep your seeds watered and when you can see roots emerging from the base of the pot, it is time to transplant into 9cm pots. Harden off in a cold frame for three weeks and then plant out in your garden and sit back and enjoy your efforts.
I am a qualified garden designer with a keen interest in contemporary, natural and traditional gardens. You can find me on Twitter or like my Facebook page where you will find lots of tips related to gardening.