If it was me, I would bottom water them, by placing them in a pan of water so they can soak it up.

are they frozen, if so dont worry. when it thaws, there should be condensation in the container. (caps are always off), Should you need to water in the spring, bottom water by placing a jug in a pan of water - about 1 inch - for a few minutes. the jug should soak it up.

Most springs I need to water my jugs, sometimes several times a week or even daily. I bottom water them putting several containers in a large plastic bin while I work in the garden, changing out containers until all are watered.

Putting containers in a semi shaded area will help keep them moist longer.

As everyone else has said, bottom water. I bought two inexpensive black cement mixing tubs at Menards (can get at any hardware store) to bottom water with. I can easily water 6 jugs at a time in each tub. Watering a jug at a time would take me for forever when I have 100+ jugs.

Sandy

When I bottom water, I use a wagon. It holds 10 jugs at a time.

I live in arid New Mexico and the first year I winter sowed I used the 2 liter pop bottles and milk jugs. There is very little precip and it was a chore keeping them watered. I had great results with the plants but because of having to water often I switched to winter sowing in styrofoam cups and put the cups in a clear plastic packer. Much easier to water with a watering can that has the shower tip - even though I have to water more often than I would with a larger container like a milk jug. If I lived in an area with more precip I would have stuck with the milk jugs but this has worked well for me.

Thanks, all. I have the jugs in a container already, we have crazy winds here, so bottom watering will be easy. I just have to make sure to keep it cleared of water when I'm not trying to soak the jugs!