c Insulating the greenhouse for Winter and Overwintering Plants | Garden, Tea, Cakes, (Books) and Me

Insulating the greenhouse for Winter and Overwintering Plants

My greenhouse is unheated, so during the winter in the UK any plants inside are afforded little protection from frost. Previous years I have lost young plants, even though they were protected with fleece. I do not want to heat my greenhouse, I know this would solve my problems and it would also help come springtime with any early seeds sowing. My alternative is to insulate my greenhouse overwinter with...bubble wrap. Used by many gardeners and if it's good enough for one of my favourite Gardeners World presenters Monty Don, its good enough for me.
how to insulate greenhouse for winter
How to insulate your greenhouse for winter
How to protect your greenhouse and plants through winter without too much expense.
  • Bubble wrap or packaging you sometimes find inside parcels makes excellent insulation. It is also a great way of reusing packaging plastic. Use a strong tape to attach it to the windows. As you can see from the photo below all my windows are well covered and protected, with the exception of a few panes in the roof. 
  • You can of course buy bubble wrap which you can store to be reused each year. Although if you are a savvy gardener like myself start collecting bubble wrap through the year, making sure family and friends know of your need.
  • To keep the environment inside the greenhouse healthy during winter you should remember to ventilate your greenhouse. So make sure you don't cover the window handles. You will be checking on your plants anyway, so opening the door or window on the sunnier days is always a good idea.
how to insulate greenhouse for winter
Bubble wrapped insulated greenhouse
Plants to overwinter
Typically plants I overwinter include:- 
  • Geraniums  
  • Aeoniums
  • Young perennial cuttings
  • Sweet pea seedlings 
  • Broad bean seedlings 
  • Half-hardy plants in pots such as Scabious
how to insulate greenhouse for winter
How to insulate your greenhouse for winter

I would love to know if you have any tips for keeping your greenhouse frost-free over winter. Someone once suggested that if a heavy frost is forecast, it's worth lighting a few tea lights in the greenhouse just before you go to bed. Apparently, they keep the temperature just above zero.
how to insulate greenhouse for winter

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  1. Hi, thanks for the follow, am following back. I like how you've called it a thermal vest. I don't have any tips unfortunately as I don't have a greenhouse and I'm not brave enough to overwinter anything inside!

  2. Google for 'thermal mass' -- too long a comment for me to explain here. Using barrels of water and all the stones, bricks and concrete pavers I can fit into my greenhouse mediates the temps by 5 to 7 degrees fahrenheit. Predicted temps below freezing, I use a small electric heater to supplement. Also google for 'Rocket Heater,' a notion I haven't tried.

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