Hi Megan-

Although I'm relatively new to the gardening scene myself, I've been doing a TON of homework on these boards over the last year. Here's some info that may or may not help you:

I have some garden beds that I've been trying to spruce up ever since we bought our house in 2003. The previous owners had every single one of our 'flower beds' filled to the brim with hostas and I want to put more splashes of color in them.

Same here. I want COLOR! If your areas are shady like mine, here's some items that I'm trying in our zone that will give some color to the shady spots:

Columbine/Aquilegia: I've got many different colors started.
Astilbe- can't wait to try these. Currently have only white started, but wanting to try the pinks & reds
Impatiens- reds, pinks, salmon, white
Forget-me-not- blue
Goat's beard
Other hostas- I didn't think I liked them at first, but when there's an area planted out with many varieties of large, small, medium, and everything from green to blues to variegated, it really looks sharp.
Geranium cranesbill

I am quite a newby when it comes to flowers of any kind so it's been quite a challenge. We finally managed to get some beautiful perennials to thrive in the beds so my next project is to fill in the open spots with annuals.

Again, same here. I've got lots of 'plans' and many items started, but this will be their first year, so I've got to plant more annuals to fill in where the first-year perennials won't be mature yet, and probably not blooming.

My question is...I'd really like to try starting annuals from seed this year (I love a good challenge) but I'm not entirely sure how early to start them indoors to ensure they'll bloom in the early summer. Can any of you give me an estimate of how early I'd need to start the following varieties for an early summer bloom?

Haven't addressed your list yet, but DO take a jaunt over to the winter-sowing forum. There are MANY annuals that we can start NOW (I just learned this the past couple days) that are hardy enough to put out. (Yes, that was 'out.' Winter Sowing doesn't take up space in your house- YAY!)

Lobelia Cambridge Blue I think this one is considered 'tender' so it would need to be started indoors, or put out late March/April if WSing it.

Tuberous Begonias same as Lobelia
Petunias Can be started now if WSing
Impatiens another 'tender' annual for us. Start WSing late March/April

Also, if I direct seed black-eyed susan vines and corkscrew vines roughly how long will they take to bloom?

Not sure on the answer to the time thing, but I have been informed by more than one person here on these boards that corkscrew vine, as gorgeous as it is, will not thrive here in Z5. (sniff!) I wanted that one, too.

One more question...how early should I be starting coleus indoors to ensure I have nice sized plants to transplant outside this spring?

I haven't started any from seed, so you might try the 'Growing from Seed' forum on that one, but I have cuttings going that I took in late October that are doing well. Slow, but sure.

Come join us on the Winter Sowing forums and cure that garding itch you've got like the rest of us!

Megan, I'd suggest that you do a quick google on each of the plants you have listed. I did one on your first plant and came up with some good information in about 1 second!!! Use a search like: petunia seed propagation or similar. Some of the plants you've listed might be a tad difficult to start from seed, and others may have specific requirements.

Good luck and have fun.
I've attached a little seed propagation fact sheet for you to give you some background, just in case you might need it.

Here is a link that might be useful: Fact sheet

Depends, too, under what sort of conditions you'll be growing them. I can get plants germinated rather quickly and on to maturity at a pretty good clip. I have a light cart rigged up, the seeds as well as growing seedlings are under lights (seeds = 24 hours until sprout, seedlings = 16 hours of light). The stronger light and constant warmth makes for faster (and in some cases better) growth as opposed to a windowsill or a table near a window, for example.

So, in my case, if a packet says 6-8 weeks before planting out, I'll opt for the shorter time; if I were growing on a windowsill or only near a light source, I would opt for the longer time.

Don't start too early, though; you'll probably end up with plants that are weak and leggy, even if you do plant them out they may not take off as quickly or look as good as the plants that are good, strong, stocky seedlings. Stick to what's on the seed packet or standard info. in the books, and don't tack on extra time.

The Johnny's Selected Seeds catalogue is a really good source for information on times to start many flower seeds. You don't really want to know time to bloom as much as you want to know how long before last frost to sow indoors, or whether you want to direct seed outdoors.

Lobelia Cambridge Blue- surface sow indoors mid April
Convolvulus Flash Light Blue- direct sow outside (dislikes root disturbance)
Tuberous Begonias- plant indoors in pots in March, wait till warm weather to place outdoors
Petunias- indoors surface sow early-mid March
Torenia (Wishbone flower?)
Impatiens- surface sow end of Feb/early March

Also, if I direct seed black-eyed susan vines and corkscrew vines roughly how long will they take to bloom? BES vines will start blooming late summer right up to frost. I haven't grown corkscrew.

One more question...how early should I be starting coleus indoors to ensure I have nice sized plants to transplant outside this spring?- Depends on your light set-up indoors.

Hope this helps some. Not all flowers will bloom early summer. They each have their own time frames depending on light, day length, genetics, etc., besides how early they're sewn.
have fun!

We buy a ton of flower plugs from a grower. We use them for a fair display at the end of July and need to know how many weeks are required for each of the varieties we use to bloom from the time we receive the plugs. They are able to supply this information for the plugs they grow along with growing temperatures required to meet this goal. Seed supply companies must have similar information for the seeds they sell. Al

In one gardening book I finally found some sow & bloom time estimates.
Sow/ Blooms
Mornong Glory (not Convolu) says 5th month/7th & on
Impatiens 5/7+++
Petunia 4/7+++
I try to sow earlier so they bloom earlier; if conditions are right that is.
A Google search should find similar info!
sam