I'm a newbie wintersowing, but I use cloches all the time, not for frost but to protect from cutworms, slugs, and birds. I don't have a picture, but I take the bottom off a water bottle, set it into the ground around the little seedling. I just take a the top off because by the time the critters are out, it's warm. If I don't have a bottle, I use buckets, boxes, baskets, crates, bowls, cups, anything really.

I've never used glass...

Last year I transplanted a couple of my tomato seedlings early into pots, and when it was going to be cold, I pushed a water bottle or a 2 liter bottle with the bottom cut off into the dirt ... depending on the size of the seedling. As it got warmer, I think it helped the tomatoes grow faster. If it was a warm day, I had to remember to remove them though. I only put the lids on at night if it was gonna be freezing ... otherwise I left them off. I also used milk jugs like that to cover some flowers I transplanted into the ground rather early. I don't know if it was necessary, but made me feel better.

I'm not sure if the glass jars would work, unless you just used them at night, but that could be a lot to remember. Others may have different ideas though.

see i "think" that glass would be a bad idea unless it was really cold or cloudy, ya know how the sun heats up, like in a car, so it'll do the same to your plants. just opinion. but it gave me an idea. cuz i was thinking of ws in them babies til she said about night. LOL i have the big jalapeno jars. i guess they'll be good for keeping big seeds in next year. like the beans i want to sow and such! LOL i hope i helped any :'))

The glass jars are excellent to root cuttings in,I save all my glass jars for this reason!:)

I use the water bottles with the bottoms cut off as well. I used them to cover lettuce seed I planted in pots. This is the first year I was able to start my lettuce and keep it becauce of the cloches. Every other year the sparrows thought I had put out a tasty treat for them and I lost everything. The plants are now touching the sides of the bottle. I feel like they have grown faster than if I had them in the pot without the cloche. I leave the tops off and haven't had any problems on the days we hit the mid 70's. I am planning to transplant some other seedlings out into the ground and I will cover those as well. I thank whoever came up with this idea with the water bottles. It solved a lot of my problems and made me think that I need to be thinking outside of the box more! LOL

Vicki

Hello there,
We learned about this in Zoology class in High school:
The original cloches were used in Victorian times and were bell shaped and made of glass. The curvature of the bell provided maximum penetration of the sun's rays as well as protection from pesky animals and such. Because there was no good way of venting, on very hot days one side of the cloche was propped open with a small stone. We do exactly the same with our 2-litre pop bottles and any glass jar could be used as well.