Sadly that's generally what happens. It's rare to find all on one site. I enjoy using Michael Dirr's Manual of Woody Landscape Plants (for trees and shrubs) which is sometimes available on ebay for a fraction of the new cost, but for perennials and annuals it's usually a websearch thing. Daves Garden isn't a bad site to check out. Hope this helps.
Regards,
Dave

You can short-cut some of the questions with this:

*sow about 1.5x as deep as the thickest part of the seed. (basically tiny seeds just on the surface of the soil, and bigger things, bury as per that 1.5x).
*for when to sow, do wintersowing (link below) and it'll sprout when "it knows is the right time".
*For height, tupe, bloom time, sun, zone, common name -- google search this " dave's garden plantfiles" and the name of the plant you're hunting and you'll get the awesome database for all of these. (I'd post a link to there, but gardenweb has made that illegal beause there is a membership fee -- but you don't need to be a member to get to the part I've said.)

That'll cover everything.

Here is a link that might be useful: Wintersowing

The short-cut answers are helpful in some cases, but aren't 100% reliable. Some seeds can't be winter sown, and Dave's PlantFiles (while often a good starting point) are filled with errors and mistakes.

With a little experience, a google search can be used to find most of the information about most any plant/seed pretty quickly. Leaning to use the correct terminology in searches (like adding the word "germination" along with the proper scientific name of the plant for information about seed germination) can go a long way. Also, learning which sites generally provide reliable info and which don't will speed up your searches. BTW, never assume that one source is correct. Always get confirmation if accuracy is important.

The seed site gives a lot of info.

Here is a link that might be useful: The Seed Site

I've used the following germination database quite a bit, though it has lots of ads on it now. I think it was originally from Thompson & Morgan. Most germination databases aren't going to give you the height, bloom time, etc., as different members of--say--the hardy geranium family can be different heights and bloom at different times. You'll need to get that info from your seed catalog. Or, if you are trading seeds, you can always look it up on Google. I also use Norman Deno's book--Seed Germination Theory and Practice--for plants which are more difficult to germinate.

Here is a link that might be useful: Seed Germination Database

For germination information, I like this site.

Here is a link that might be useful: ORGS Seedx

These two sites are excellent as well:

Tom Clothier's site has germination databases for perennials, annuals/biennuals, penstemons(?!?) and trees/shrubs

Tom Clothier's germination database

If you can't find germination info at any of the above. B & T World seeds lists 35,000 seeds and has germination info for many of them.

You can look up plants at:

B&T World Seeds search