It's too soon to start most things under lights. The only things I have under lights as of yet are cuttings of annuals and tender perennials I took in the fall before frost: torenia, scaevola, plectranthus, and salvias.

If you want to start annuals (like your poppies, larkspur, etc), you need to find out your last frost date in your area. Here in Meridian, MS, that date is April 15. I count back six to eight weeks from that and that's when I start my annual seeds under lights. I'm going to wait until 6 weeks out before I start them this year. The plants just really don't like being in pots too long and once the soil warms, they take right off.

If you want to start perennials, it depends on the perennial. You want to learn all you can about the conditions that make the seed germinate (the same goes for annuals, actually). If the seed needs scarification, I have had great luck sowing the seed into pots and just setting them out on my back deck where they are cold and wet through the winter. They come right up in the spring. Some things I have started that way: heliopsis, baptisia, platycodon (balloon flower), shastas, etc.

If you have a good Metal Halide grow light, you can start perennials now and have them reach a good size by spring. I've already started echinaceas I crossed so I can see them bloom as early as possible. If you only have those shop lights which many do, you shouldn't attempt anything right now.

Check the seed packets for sowing instructions. They'll typically give a time range such as 'sow 6 weeks before planting out'. The longest I've commonly seen is 12 weeks, so it can vary a fair amount.

There is also quite a bit of possible variation in planting out times. Tender annuals go out after what is commonly called the last frost date. This is more accurately the date where nine years out of ten, the last frost has already happened. Around here, at least, the last frost is almost always in the forecast in that tenth year, so paying attention to the weather is a must.

However, hardy perennials can go out sooner. Here, I time the planting of hardy perennials to be about a month earlier than the last frost date.

If you have adequate cold frame space, earlier start times are feasible. The problem with trying to grow starts through seeds or cuttings prematurely is that you get pale, lanky plants through delays in getting them into warm sun (unless you're willing to run up an electric bill with high-powered lights for an extended period).