[Headgardener22]

Hi,

I have a question to which, having trawled through many posts on insulating greenhouses and polytunnels with bubblewrap, I can't find an answer.

Do gaps matter?

Having bought my bubblewrap, I'm putting it up in my polytunnel by running wires end-to-end and putting the bubblewrap over the wires. Fairly obviously there are gaps between the sheets of bubblewrap. Should I move the bubblewrap closer together so that  the sheets overlap or does it matter that there are gaps.

Along similar lines. If I have enough bubblewrap, should I put multiple layers in the roof (I've seen in some posts that people suggest two layers in the roof of greenhouses.

When I watched Monty Don putting up his bubblewrap, he seemed to use yards of sticky tape to hold it all in place but I don't want to do that unless its a good idea.

Thanks for any comments.

[sunshineband]

Just think about what the bubble wrap is there to achieve --- a layer of insulation under the glass, to protect the plants further from freezing air outside the greenhouse.

So yes, gaps do matter as the slightly warmer air rises , and the colder air falls down.

Overlapping the strips of bubble wrap should do the job without yards of sticky tape, if you can hold it reasonably taught. Long strips that make a sort of tent, supported on a wire in the roof and one at each of the eaves can do a good job.

A further panel hanging down back and front might need some tape to keep it all up OK. Done my home greenhouse like this for years.

Not sure about adding more layers, as it cuts down the light even more.

Hope that helps