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Greenhouse temperatures


by Pippa Greenwood

The temperature in my greenhouse is fluctuating wildly. It rockets during the day, when the weather is sunny, then plunges at night. The contrast is far more marked than last year.


HenThe temperature in my greenhouse is fluctuating wildly. It rockets during the day, when the weather is sunny, then plunges at night. The contrast is far more marked than at this time last year.

This year I delayed sowing many crops, and I almost wish I had waited a little longer. I’m constantly venturing into the greenhouse with sheets of horticultural fleece, to provide young crops with extra warmth at night, then opening the doors and windows during the day (the wretched automatic vents have failed again).

The temperature has been so high during the day that I’ve had to remove the lids from two propagators, to prevent them from ‘boiling’ the seedlings. I keep a couple of watering cans close by, as the plants are guzzling water at such an incredible rate. The water gradually warms up to greenhouse temperature, which is much better for seedlings than ice-cold water, straight from the butt.

I’m not the only one dashing about. Recently one of our hens had a funny turn, so we put her, temporarily, in a nice snug box in the greenhouse. After an evening of luxurious rest, she ventured out of the box to explore, wreaking havoc in the process.

We’ve released her back outdoors, and hopefully she will now settle down. Now, if I can fix the automatic vents, and if the temperatures even out, order will be restored…



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Gardeners' World Web User 09/03/2011 at 16:22

Know exactly what you mean! Same with me. Into greenhouse twice daily to open up or close down....hopefully it'll settle down soon.

Gardeners' World Web User 09/03/2011 at 18:40

I know exactly what you are saying - my first year with a poly tunnel, it goes from -1 over night to over 30 in the day, crazy!

Gardeners' World Web User 09/03/2011 at 19:14

I have no greenhouse but a conservatory attached to the house which is connected to the house by patio doors into the lounge and the fluctuation in temperature is controlled by opening and closing the door. No precious heat is lost as it heats the lounge. Being double-glazed the frost does not reach the plants or seedlings. I'm sure I've blogged before about living in a garden with a house attached! But seeds are cheap so you have time to start again if disaster strikes from sowing too early.

Gardeners' World Web User 10/03/2011 at 06:47

I have bubble wrap top to bottom with no heat and like you say temps are up and down some of the veg is coming up the best way I find is to fleece newspapers and cardboard fruit boxes from supermarkets veg shops gives that little extra protection i have delayed some crops as were a month behind anyway in the northeast

Gardeners' World Web User 10/03/2011 at 09:05

I to have bubble wrap top to bottom in my greenhouse and a small electric heater. I don't have automatic vents so I just open the window a little bit and turn the heater off once the sun is getting onto the greenhouse. I try to time it right by switching the heater back on and closing the window early afternoon when the sun has gone, so far my seedlings are coming up really well. I have managed to keep the temp just above freezing for most of the winter.

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