No seeds are guaranteed to germinate 100% of the time for many many reasons

Depending on where you get them and how old they are the germination will increase and decrease.

FYI always take off your humidity dome when the first seeds germinate.

The dome is not necessary and used as a convenience to keep humidity high and soil moist.

They can be deadly if left on too long because the humidity is a welcome sign for dampening off for young seedlings.

Keriann~

There are question---
How warm is your heating blanket? You should be barely able to feel the heat. Too much heat will kill the seed.

Is this saved seed? This years seed? If it's new seed that's a poor germination rate.

I don't know about eggplant or cress, because I've never grown them, but some of your seed would be better off planted directly in the garden--namely sweetpeas, peas and lettuce. These are cool weather plants and germinate at lower temperatures and a light frost won't bother them. Your lack of success with these may be that the soil temperature was too high.

I am also having real problems this year. THis is my 3rd year starting from seed (morning glories, castor beans, sunflowers, thunbergia etc., and it's been unbelievably frustrating. I bought three 4ft. grow lights and thought this year would be so much easier because of my 'professional' set up. Well, I've planted 30 morning seeds, and got 5 seedlings. My first castor beans sprouted then died, and now I'm re-starting them in milled spaghnum moss-they're immerging, but way too slow, and out of 8, I've lost 3. I've changed from a seed starting mix to soiless because of the damping off. I can't believe how much trouble I'm having with seeds that are really so simple to start. Help!!! :(

Describe what type of containers you are using, have you sterilized them, are they covered, how often are you watering, and did you soak or nick the morning glory seeds prior to sowing them?

For what its worth..... I was trying to germinate Marketmore 76 Cucumbers and it took 11 days to germinate. This to me took way too long as I was using the oven light to create heat and my wife wasn't very happy about tying up the oven. I then went out and purchased a Ferry Morse (jiffy) Heated Proffesional Greenhouse @ Lowes for around $32.00. The next batch I did was of the same seeds and took less than 48 hours to germinate. This made everyone happy :-)

I tried a dome for the first time about a month ago, and had terrible luck with it. My seeds cooked and my sprouts rotted, even after taking the dome off.

I decided to try again without the dome, controlling the conditions a bit more, misting morning and night. So far, this seems to be working pretty well. The Phacelia all sprouted by the 3rd day, the onions by the 4th day, and the licorice mint by the 5th day. Now, on the 7th day, I also have a pumpkin sprout, a watermelon sprout, a peppermint sprout, two ground cherry sprouts, and two strawberry sprouts.

I'm really hoping that a few more of each will come up over the next couple of days, but I can at least say that I'm doing much better now than I was with the dome.