Ideally, you want to remove the plastic cover and move the seedlings under good light as soon as the first couple seedlings sprout. You can't leave the covered containers under artificial light or exposed to sun while you are gone because temperatures will rise too high. The other risk with those plastic covers its that they create the perfect environment for growth of fungus on the soil surface. I started pepper seeds under one of those covers last Saturday, and saw a bit of white fuzzy fungus on the soil surface three days later. Fortunately, I was here and able to remove the cover. I've moved them under my plant lights even though the seeds haven't sprouted, and the mold has disappeared. I don't know what would have happened if the cover remained on for another four days, but I don't think it would have been good.

You might try propping the covers so the humidity doesn't build up too much. Another alternative might be to ensure that temperatures are lower than optimum to delay sprouting a day or two, but that can be risky too. If I were you I would wait until I returned to plant the seeds.

Agree that you'll have 10x the success if you wait until your return to start them. Nothing at all is gained by starting seeds when they will be left on their own while at their most vulnerable stage.

Dave

I say give it a shot. I did it once. Soaked them down good and came back a week later and they were fine but thirsty.

Or you might try not watering them a couple of days and then sit them in a little bit of water. The water will soak up from the bottom and you'll get a few days watering out of that which should put you in the clear..

Let me be a little clearer. I have nothing to lose here. I am going to plant a ton of tomatoes, regardless of what happens to these, and I'll start those the day I get back.

This is my shot at an ultra early (for me) group of plants, with which I am going to try Wall of Water. What I really need to know, because I haven't kept track, is how tall are they likely to grow in the week I am gone, assuming that they are just popping through when I leave. It's it less than 3 inches, I think I have a pretty good shot.

Well, if you don't mind losing them, then go ahead and try. But, like I said, if they are under cover and have sprouted, bright light will cook them. If they're not in bright light, it's unlikely they will grow more than an inch or so. I would leave the cover off, saturate the soil and set them over a humidity tray in moderately bright light.

I don't think they will hit the 3" mark in a week. It's only a few days and if your attitude is "what can I lose, I'll start a new batch when I get home...." go for it. What have you got to lose? ;-) Let us know how it all turned out. Inquiring minds here!

Here is what I came back to yesterday. This is an assortment of indeterminates which I sowed about a quarter inch deep on 3/10. They hadn't emerged by the time I left on 3/14, and there was a lot of gray fuzzy stuff growing on the wood. I watered them very well and put on the clear plastic cover and headed for Mexico. 30 out of 32 germinated, and if you can't tell from the picture they are doing quite well.

This post was edited by Creek-side on Fri, Mar 22, 13 at 19:29

Congratulations! I will admit that I didn't expect your tomatoes to do so well under a dome for that long. I am glad to learn I was wrong.