The problem is that you have a lot of soil exposed to the air inside the container. Since there's more air, warm air, there's more chance of them drying out. You just have to be a little more careful with them than you would a 2-liter container. That's one reason I use them mostly for annuals or seeds that are quick to sprout. I water mine a couple times a week now that it's gotten really warm. I even took the top off the hoophouse today where most of them reside. I'll be watering a lot more over the next few days.

On days like today 68 degrees, should I open the tops of jugs/liters that have germinated? Fine mist spray of hose to water them? Won't it harm the tiny seedlings?

I don't have mine off yet, but I probably will soon. I water with a mister. It won't kill them. They're good. Just remember, rain and snow have been pelting them. You can't do much damage unless you absolutely drown them.

pippi: I've been taking tops off jugs with sprouts for several days. We had warmer than usual temps this week. Yesterday, I put an instant read thermometer inside several jugs - temps 85-95,+ I took all tops off.

I thought winter was over. A few minutes ago, talked to DH who is in Shreveport LA. Temps are in the mid 40s, light SNOW is forecast for tonight and tomorrow.

If we have a cold snap, throw a blanket over the jugs. The cold snap will be over fast.

I had snow today light but all over our deck drive melted right away, I heard in Ok that they shut down roads because of snow ??

I saw on the news this am that OK, and parts of Kansas got 12 inches snow.
ugh.