Build a frame against the back wall of the structure to stack those 55 gallon drums three high and keep the front row low so the most surface area is hit by the sun.
Insulationg concrete floor greenhouse.
The thicker the better of course.
Concrete will also reflect light and retain heat throughout the day.
The thermal mass of the stone will absorb and then release the solar energy stored during the day.
That is why pea gravel is a good option.
One recommended option whether you use a slab or wall is to fasten a 2 x 4 sill on the top of the foundation.
Even an insulated year round greenhouse doesn t need a finished floor as a house does.
The best material for a solar greenhouse heat sink floor is some kind of stone or concrete.
Install a drain in the center of the floor that leads to a gravel pile underneath the greenhouse or to a pipe to carry.
If you poured a concrete slab for your greenhouse foundation you have a perfect floor as a bonus.
What to use for greenhouse floors.
Most of the footprint will be used as a planting area which may or may not need a level finished surface.
The most ideal is a poured concrete floor especially if it s insulated.
You will add spray foam insulation either polystyrene or polyurethane under the greenhouse floor in the next step.
A concrete floor is easy to clean and walk on and if poured correctly should drain away any excess water.
Leave a 1 inch trench 12 inches deep around the external edge of the foundation.
At ceres we go one step further and actively heat the soil using a ground to air heat transfer gaht system.
This uses an airflow system to actively draw hot air from the greenhouse underground so the greenhouse can store more heat in the soil.
Your flooring option usually depends on how you want to grow in the greenhouse whether growing directly in the soil raised beds or in an aquaponic or hydroponic system.
Apart from providing good drainage the best greenhouse floor should insulate the structure when it is cold outside.
Insulation quilts over the greenhouse at night keeps more heat from being lost.
It absorbs heat from the sun and releases it into the surrounding environment during the day and night.
This insulates the floor and helps keep it warmer in the winter.
Neither do we insulate the floor this should be left un insulated so the greenhouse so it can absorb heat from the greenhouse.
A concrete slab may be the easiest type of greenhouse footing to keep clean.
Concrete especially if it is insulated provides an excellent floor easy to clean and to walk on.
You want heat exchange to occur between the greenhouse environment and the thermal mass of the soil.
The sill acts as a insulated buffer between the concrete and the greenhouse frame reducing heat loss.
If poured properly it has sufficient slope to drain away the excess water.