Safely Heating Indoor Greenhouse (PVC)?

[ChilliFlower]

Is there a safe way to heat up an indoor greenhouse with a PVC cover just a little bit more when the weather is chilly? I have this model https://www.wilko.com/en-uk/wilko-mi...ouse/p/0476578 and would like to bump the temperature just a little bit more

[Scarlet]

I don't think so....what do you intend putting in it?

[veggiechicken]

Do you have it "indoors" or outdoors?

[quanglewangle]

You might consider the sort of soil heating cable used for propagators, buried under a layer of damp sand.

Be aware though that the domestic 13A plugs on them are not water, or even moisture, resistant. 13A plug should ideally be replaced with the blue 16A plug/socket thingys used for caravan hook-ups and shore power for boats. Protect the extension to the greenhouse with a RCD. If none of this made sense don't do it.

[ChilliFlower]

It's indoors fully; in my kitchen to be exact! It's in the window to get the best of the sunshine (what little we have ...). At the moment, it is a nice 18c roughly at night and 21-22c during the day. This is more or less for the future if the cold snap comes and is brutal.

I grow chilli seedlings in there at the moment, as well as some of my resting orchids and two bromeliad pups, as well as a gasteraloe that is recovering from abuse whilst in a supermarket.

[quanglewangle]

All my comments were assuming it was outside. Inside is loads easier. Have a look on Amazon for 'Terrarium Heat Mats'

[Scarlet]

I don't think it's that wise to up the temps any more - more heat and not enough light will give very leggy plants.

[Jungle Jane]

I don’t think they’ll need any more heat,a lot of my plants are on the windowsills,we have some cold days every spring,they’ve always been alright. My kitchen hasn’t got heating the plants are next to the window yours should be fine how they are but careful they don’t get too warm in there on some days.

[veggiechicken]

I don't think it's that wise to up the temps any more - more heat and not enough light will give very leggy plants.

Also, when you water your plants inside a heated, enclosed space, you create humidity and risk your plants rotting.
With the temps you have, I'd be looking at increasing ventilation, not heating.

[Mark_Riga]

Something like the 20 or 30watt lights may be ok to slip in on a chilly night and they also give a good light so could double up as a loft light and may be stop your plants geting too leggy. IP65 rated so should be OK in a dampish atmosphere.
Not sure if they would be sufficient heat and they might be a bit big if your greenhouse is full. The measurements on the £12 and £15 ones look wrong. You could try putting in a table lamp with it empty and put a fairly low bulb in and see what it does if you have a thermometer.

[veggiechicken]

Water & electric don't mix. See qw #4

[Urban]

I don't think youl need any extra heat to be honest if you keep it inside. I think the perfect tomato growing temperature is around 21c for example. They won't mind it dropping down to around 12c for a few hours overnight

If you really insist in some extra heating I reckon I'd try something like this https://www.amazon.co.uk/Dimplex-Eco...E0E7BEF55BF9E4