Double Lid

I found that I was getting a minimum of -2 C inside temperatures so I installed a second lid on the ground inside the cone. This made a double lid - one on the ground and one on the top of the cone.

The lid inside will need to be removed once the plant grows through the soil surface, but for now it will add extra insulation from the cold.

I had set out a row of Mini Cone Greenhouses for a day to prewarm the soil and this shows that it did that nicely. The soil inside where the cone had be set was damp and unfrozen while the soil outside had snow on it . I am still having discrepancies between my thermometers,  so am now charging batteries in the second thermometer and then will plan to do a calibration between them and another standard perhaps more reliable thermometer. The soil inside a cone, however, is clearly kept warmer than outside. Also it looks like with the lid on the top of the cone, the soil inside is kept moist, perhaps by condensation. Still need to make a watering plan. Maybe watering won't be necessary for a while.

Here is a double row for a total of 20 Mini Cone Greenhouses installed at the edge of a garden.

Here are 10 Mini Cone Greenhouses pre-warming the soil along a fence line.