Creating a Winter Paradise
After enjoying several evenings in the greenhouse, I have decided that I would like to extend the use of the greenhouse throughout the winter and create a little winter paradise. The tomatoes are gone but I have acquired several exotic house plants and am hoping to create a pleasant plant filled space where I can sit during the day and on into the evening if I wish.
The Victorians used to import exotic plants from all over the world, which they successfully protected from cold winter frost in their glass houses and conservatories. Though they also used quite intensive heating systems consisting of fire, boilers, and piping ducts to maintain the temperature, plus a young trainee gardener to keep the boilers stoked, throughout the day and night.
I have read that greenhouse temperatures should stay five degrees warmer internally overnight than the outside temperature. This should be fine during mild weather, but I will need to protect the plants during cold nights.
I have been doing a little bit of research and have discovered that tropical house plants don’t enjoy being below ten degrees as a rule. Whilst they are actively growing throughout the summer, they require warmer temperatures but whilst they are dormant, will tolerate cooler temperatures. I also have a citrus tree and overwintering pelargoniums which both dislike temperatures below seven degrees.
The bargain house plants that I acquired during my weekly supermarket shop all arrived in very stingy plastic pots. They were so small that not only were all the plants totally pot bound, but the plants couldn’t even stand up un-supported. For the plants to thrive and not fall all over the place, they would all require much larger pots. Luckily for me, I know a farm which specializes in very potent Somerset cider and some quite unique garden reclamation and is just half a mile from where I live. I acquired some nice big, heavy-duty pots, that will be able to resist any frost damage and hopefully protect the roots of the plants, whilst giving them space to grow.
I spent a lovely, sunny afternoon in the greenhouse potting them up and placing them strategically around the space. Whilst the sun was shining the greenhouse remained warm and cosy, but I am aware that there will be some very significant variations in temperature throughout the winter.
Tender Plants in the Greenhouse
It might be a good idea to invest in a decent greenhouse thermometer but who will be reading it in the middle of the night I have no idea. Though it would be a useful method of assessing how effective any methods of greenhouse heating are. Also, it would be common sense to keep an eye on long-term weather forecasts so that any overnight frosts can be anticipated, and practical measures taken to protect the plants.
Several measures can be taken to protect tender plants in the greenhouse from frosts. Some people like to line their greenhouses with bubble wrap, which acts as insulation, and apparently the larger sized bubbles are more effective at maintaining the heat.
Paraffin heaters are an effective way of keeping the greenhouse warm and once filled can burn up to three days, depending on their size. On the downside they can smell quite strong, and both paraffin and propane heaters release a lot of moisture into the greenhouse. This moisture can build up and cause problems such as mold and rot in the plants. It is important to ventilate the greenhouse on any sunny days, to allow fresh air to circulate and remove the excess moisture. Electric heaters have the advantage of not producing any moisture and can maintain an even temperature, but of course they will require an electricity supply.
Watering during the Winter Months
Overwatering can be a problem for plants in a cold greenhouse. The water in the soil can freeze which will damage the root system and kill the plant. Plants in the greenhouse should be watered sparingly during the winter months, probably only once a week at most and maybe only every other week when it is very cold. It is also best to water in the morning so that excess water can drain out of the pot before night temperatures fall. It is also important to remove any wilted or dead leaves as this will help prevent the build up of Botrytis, a damaging fungus, which can spread to other plants.
Horticultural fleece is useful for adding that extra layer of insulation to protect delicate plants. It is versatile enough to be draped around individual plants like jackets, or over trays of seedlings or cuttings like a blanket. It is important to remove the fleece as soon as conditions allow so that enough light and air is available to the plants. Often it will only be needed overnight.
I recently watched a Youtube film called Erica’s little Welsh Garden, where the greenhouse owner lit a one-hundred-hour candle in a snow-covered greenhouse. Her results showed that a single candle helped to keep greenhouse temperatures up and the video also received some helpful tips. It was suggested that the candle be lit and placed under a terracotta pot, positioned on the greenhouse floor. The flame from the candle will warm up the pot and radiate heat. It is also safer than having an unattended open flame. The bigger the greenhouse the more candles can be lit. I am definitely going to give this a go.
Hopefully these measures will help to protect the tropical plants from frost damage and allow the pelargoniums and citrus tree to survive winter. I am aware that this is an experiment which might go horribly wrong and if there is to be a period of cold weather, I will bring all the plants inside as a precaution.
A New Fire Place
These measures are in place to protect the plants, but if I want to sit out on a winter evening, I will need something a little bit warmer. My husband obtained an attractive mobile fire which uses bio ethanol fuel. Bio ethanol is a renewable energy source made from fermented sugars and starches, obtained from plant by-products such as maize and sugar cane. The fuel is a more environmentally friendly product than propane and paraffin and releases less emissions.
Once lit, the fire soon warmed up nicely and burned for up to three hours. It generated a nice ambience and a pleasant temperature so that we could enjoy a glass of wine and sit in the greenhouse in comfort. I did need to move the plants a safe distance from the fire as they were at risk of scorching, but it was a very pleasant evening.
With all these precautions, I am hoping that I will be able to extend the use of the greenhouse throughout the winter months. Unfortunately, I have just seen the weather forecast and it looks like we’re in for several nights of severe frosts. I will soon know how effective these precautions are. Fingers crossed.
1 Comment(s) on this post
10 Dec 2023 10:18
A lovely article- would it be possible to get some more information about the mobile fire - a link perhaps?
14 Dec 2023 14:26
Thank you! We're happy to hear that you enjoyed reading the article!
The mobile fire in the article is a free standing ethanol fireplace from HOMCOM. It has a 1.2L tank and a 3 hours burning time. I hope this helps.
Anna from the Greenhouse Forum
Om Sian Napier
Sian Napier is a freelance garden designer and gardener with over 15 years professional horticultural experience to build beautiful garden spaces for her clients using plants to create movement, texture and all year season colour and interest.
Follow her journey of living with a Gabriel Ash Greenhouse and learn about different aspects of growing through the seasons.Get to know Sian Napier
- Current blog posts
- Three tips for the greenhouse
- For the plants to grow it takes fertilizer but which one?
- Sterile soil is not good for the plants
- Greenhouse plants also get sick
- Hens in the garden
- Provide shade for your plants
- The philosophical gardener’s theory of perennials
- Create good living conditions for animals and insects in the garden
- The golf courses great secret
- What you need to be aware of when growing in plastic