I'm wondering just how much light bubblewrap "double glazing" in a greenhouse absorbs. I've now got aubergines and tomatoes at the seed leaf stage. They are on the shelves of a small plastic growhouse in the greenhouse with a heated propagator in the base which keeps the inside of the growhouse at a minimum of about 15C. I'm anxious that they don't get leggy. The available light is having to pass through the greenhouse glass, then the bubblewrap and finally the plastic growhouse before reaching the plants. If I remove the bubblewrap from the greenhouse glass then they will get more light. Just how much light will a single layer of bubblewrap absorb? When do most people remove the bubblewrap? I had been thinking of leaving it until I clear the GH out prior to planting (in pots) tomatoes etc., but maybe I should do it earlier to increase the light levels. All views/ideas welcome.

Regards

Ian

I honestly don't know, but I think light intensity levels are starting to increase more rapidly now. Is the whole of your greenhouse lined with bubblewrap, or could you conveniently slide back a section of it during the day in the vicinity of your inner greenhouse when daytime temperatures are warmer, and slide it back at night when it's dark to provide some extra anti-frost protection?

Here is a link to an old thread.

viewtopic.php?f=15&t=4982&hilit=correx

As it describes, I have permanent bubble wrap on the North side of my greenhouse and removable Correx panels on the South side. I remove them soon after I plant the Tomatoes, about the third week in April.
Bubble wrap would probably last longer if it is taken down each year but my aluminium greenhouse doesn't support those fancy plastic clips so it is fitted using plastic washers and self tapping screws, this means it is a long job so it stays in place.

Thanks for the comments. The growhouse is in the Southwest corner of the Greenhouse so the light is as good as it can be. I'm going to remove the lengths of bubble wrap from the glass next to the growhouse and just accept the reduction in insulation. I have a thermostat set for 5C in the greenhouse itself so the growhouse temperature will stay OK with the 60Watt propagator in its base. If the long range weather forecast I've seen proves to be right, (mild, wet end to Winter), I could take off all the bubble wrap. Not yet I think.....

Regards

Ian

I keep a third of my greenhouse completely lined with the large size bubble wrap and leave it on until the end of April when the tomatoes are too large to stay in their pots and have to go into the borders.

I do use a lamp though to increase the amount of light over the propagators though so things don't get too leggy.

I've heating cables in the borders which I turn on when the tomatoes first go out and they seem to do OK with fleece handy to cover them when we get a frost. They sometimes do turn a bit blue though and would like to be warmer really.