1. Build a wooden frame - I used 10x10cm fence posts.

2. Collect a lot of glass jars - I asked my office canteen to save their empty jars for me.

3. Stack the jars with the open end inwards inside the wooden frame.

4. Fill the gaps between the jars with moss - depending on where you live you may want to spray the moss with water.

5. (optional) I tiled the floor with the lids from my jars.

6. (optional) big jars make great seedling starters (mini greenhouses)

7. (optional) collect rain water in a jar and siphon it into plants. (see photo)

8. Roof - I am still looking for a really good solution, first i just had a sheet of plastic stapled on. My second attempt was with some termo plastic sheeting - this looks better than tarpaulin and it insulates better but not easy to find as a recyclable material... I think perhaps a "green roof" (grass/living roof) would be optimal. then perhaps use some jars or bottles as skylights... but I dont have a good solution for actually building such a construction (yet)

Step 1: 1. the Wooden Frame

I used 10cm x 10cm "fence" posts ... which worked out quite nicely with the average height of my glass jars.

My greenhouse is "free standing" but I guess it would be best to have some sort of foundation if building on grass - the final structure is quite heavy.

It is important not to make the spaces between the posts - too large, stacking the glasses can be tricky - and if they are high up can be dangerous.

Step 2: 2. Glasses

My greenhouse is roughly 2M square - and when its finished will probably have used about 1000 jam jars. (and i have only filled 3 out of 4 walls). I asked all my neighbours and colleagues to bring me their jars. The canteen at work was also great for getting over sized jars - the big jars can have multiple uses.

Step 3: Rain Collection

I 3D printed this adapter to collect rain water. The files are available from thingiverse.

I am working on an updated system ... coming soon !

Step 4: Floor Tiles

I mixed some fine gravel and a bag of cement (no water) - I spread the mixture on the floor about 1cm deep.

I then pressed in the lids, trying not to think about the order and colours. (I like the random look)

After a few days the gravel/cement mixture had absorbed moisture from the air and had set.

tip - I was amazed at how many lids were required to tile the floor. You might want to make sure you have enough lids before you start setting them in cement.