Yes, you can start them now from seed, anytime between now and about early Sept. I personally would say morning sun and afternoon shade to avoid the soil baking on hot days and drying out too much, but I'm not home on the weekdays to tend to them. Pots/trays/cell packs all would work. As far as coming true to seed, hard to say. Genetics is always a mystery to me. Many things come close to the parent, in my experience, not necessarily exactly the same but similar. Every once in a while, something is radically different in some way, but that has been the rare exception in my experience.

Hi hanzrobo, I have an east facing and a huge south facing window. I was a little concerned that if they slow down in the heat of summer, seedlings may have a tough time right now. We are already 100+ and the room they will be in is warm! It's an add on to the house, but no cooling attached. I'm thinking of ordering seeds from Mesa Garden , unless someone has a better suggestion. :-)

Have you tried growing any Dahlias? They grow rapidly in warm weather. They are usually started from tubers, which may be hard to find at this time of year, or cuttings rather than seed. You could buy some potted Dahlias and plant those and also at the same time take cuttings from the mature plants in order to make more plants. If you're buying potted Dahlias make sure you don't get dwarf bedding varieties.

You can sow seeds at ANY TIME OF THE YEAR. I sow something just about every month. Using the most basic logic, seeds are dropping from the mother plant with prolific enthusiasm, right now...but they have their own innate timing, so providing we avoid mucking about with bizarre chemicals, setting up complex lighting schedules or broiling them on heat pads, the seeds know what to do as long as they are in a sympathetic situation...ie, as close as possible to their normal environment...and experience conditions, including a winter chilling and cycles of warm and cool which they would expect in a natural state...and here lies the rub because we don't just want plants which grow in our climate or soil type...no no no - we want tricky divas which need coddling and protecting. Plants which turn up their toes with a hint of frost...although essentially, the same rules apply - to replicate the cycle and conditions of the plant's native range. I have absolutely zero intention of faffing with seeds to raise difficult plants. The germination is the first testing for plants under my neglectful regimen - which is... sow outside when I get around to it, water once and leave them to get on with it...or not. Attrition and winnowing really sorts out the feebs and fusspots, so preventing mucho disappointment further down the line after time and effort has been invested with watering and potting on (the actual sowing couldn't be simpler or faster). Sow shedloads and you will be grateful for the fails when the awful realisation of dealing with hundreds of seedlings finally dawns (sometime around late May...just as the season hits fever pitch with maximum demands on the exhausted gardener.