Greenhouse heating

[Rosefriend]

Can anyone help me with GH heating systems. As we are now getting a "proper" GH as well and with the mess that I have in Spring wondering how on earth I can do my dahlias I wondered if we shouldn't invest in some kind of heating just to keep plants over the zero mark for a few weeks until they can go outside.

I have looked on the web and here in Germany there isn't much of a choice and the only thing that seems to be used is oil for lamps - electricity is far far too expensive. The GH will be only 3.6m2 - so not big.

Any advise is welcome as I haven't a clue...

RF

[Auricula]

Paraffin heaters are good and cheap, but they create condensation However, that's what I used when I lived somewhere where we had frosts. Now, I just light a candle if we are forecast for a cold night.

[Ladygardener]

I was thinking of your Dahlia Rosefriend. Would it be at all possible to put a small growhouse inside the greenhouse and grow your Dahlia on there? Or could you put bubble wrapping around an area of it like a little grow place.

[Rosefriend]

We have just ripped our large  WIG to bits - just in time - it was in a terrible state. The new one isn't the same size inside, just outside, but I think I might be able  to get one small GH inside...will post pics as son as I can..
Wonderful day today - weather forecast is for very cold weather again though....

RF

[andy]

I would do as LG has said and maybe partition a section of the greenhouse off. You could possibly then use one of those electric frost free heaters when required.

[Rosefriend]

I am not interested in heating throughout the winter as it would cost a fortune and anything electrical is definitely not on - the prices here are terrible. However partitioning a part off or a mini GH inside are ideas that I will follow up....

I had a google and saw this mini heater as well.. Sorry it's in German..

www.yatego.com/gekaho/p,497330158cfd0,49258e46c82122_4,frostwaechter-petroleum-gewaechshaus-heizung

RF

EDIT: Sorry the link will have to copy/pasted..

[Ladygardener]

There are some very nice wood burners there Rosefriend if only I had a spare 4,000eu and somewhere to put them. Did'nt make out any mini heaters 'tho.

[Rosefriend]

This is what I intended to show you Ladygardener..to heat a GH up to 4sqm2 (enough for mine) - petroleum oil - tank 2.25litres - lasts 14 days - 39Euro plus Petroleum.

What do we think?

[Ladygardener]

I don't know about these heaters at all Rosefriend as I've never used one sorry. I would think however that it would work well for you and you'd only be using it for about 6- 8 weeks at the most so it would'nt work out too expensive would it.

[Rosefriend]

That's the idea anyway Ladygardener - 6-8 weeks - just so I can get the tubers, corms, seeds started and the really tender stuff on windowsills...

Hope someone knows about these things!!??

RF

[Auricula]

That's the one I had Rosefriend . It was very successful when I lived in chilly Essex

[Jasmine]

Someone asked this question on GQT a few weeks ago Rosefriend and they said to avoid the heaters in your pic as they create condensation which can lead to moulds. Most of the panel said to go for the dearest thermostatically controlled electric heater you could afford as it would pay for itself in the end through no lost baby plants but that is no help to you with the cost of electricity in Germany.
I think the idea of a growhouse in the GH is a good one.

[Rosefriend]

Been telling OH about it all and I think we will have no other way as to do a GH in a GH....will start having a think whilst dismantling the GH today..

RF

[Auricula]

I found that those heaters, as in your photo, only caused condensation if they were on all the time, day and night, all winter.Too much plastic insulation would also cause condensation. Lots of fleece is good

[Ladygardener]

My growhouse has no heating but I use the bubble wrap and it always has condensation, even if I just close it overnight as I'm doing now. It's quite manageable 'tho.

[Rosefriend]

My little ones do as well Ladygardener - the only thing that I have got in the back of my mind is that if I have tender plants in and I can't open the door to get rid of the condensation as it is too cold, I am not sure what I do??

Rf

[Ladygardener]

Hopefully from here on in the weather will improve for you Rosefriend and you'll be able to open the door for the time it takes to wipe some of it away. I don't do mine every day when it's really cold.

[Rosefriend]

Well after a lot of mess and working out what I could and couldn't manage I have got this...




I can put it on 100W through to 500W. When the temperatures reaches 5degCplus it cuts off. All I need.

I worked out the cost of paraffin oil here which is expensive - 4 litres for nearly 18Euro and the wicks plus the heater which was 40 Euro and as this only cost 17.90E and the price of electricity would be just under the price of the oil I decided to do for it.

If I can manage to get just one month extra in a growing season then I am happy....I don't need anymore.

RF

[Auricula]

Well done RF hope it's successful for you and your dahlias

[Jasmine]

Looks smart Rosefriend - hope you get your extra month.

[Ladygardener]

Hope it really helps Rosefriend you'll need it this year that's for sure. Love the colour of it too.

[TeeGee]

Contrary to public opinion I find 'electricity' the most efficient and considering oil & gas are equally as expensive, I think in the long term 'electricity' is the cheapest!

I would point out one thing I was advised many years ago and I have stuck to it ever since and that is;

If it is going to cost more to heat the greenhouse than the cost of replacing the plants you are protecting, then do not heat it and replace the plants!

What I like about my system (see here) is its control ability!

Do not buy any heating appliances with a poor thermostat on it!

Cheap thermostats may be only accurate to +/- 5° meaning it might be on when not required, and worse still; off  when it is required 

My stat is accurate to +/- 1° and I only use the heater to keep the general atmosphere above freezing, currently I am holding 4°C (40°F) now that I have lots of plants on the go, during the winter months I had it set for 1°C (3°F)

The best form of heating I find is a 'hotbed' formed with either thermostatically controlled under soil cable or mat.

I can get get 15 standard 350 x 200 (14"x 8")  trays on it, whereas a propagator might only hold two at best!

My set up of a 12 m (40 ft) cable (80-100 watt) and the stat cost around the same as a large propagator to buy, and it uses about a similar amount of electricity but I have six-seven times the heated area!

So I would not count electricity out just on economic reasons, used properly it can work out the cheapest way to heat a greenhouse!

[Rosefriend]

Apr 1, 2013 15:10:51 GMT TeeGee said:

Contrary to public opinion I find 'electricity' the most efficient and considering oil & gas are equally as expensive, I think in the long term 'electricity' is the cheapest!

I would point out one thing I was advised many years ago and I have stuck to it ever since and that is;

If it is going to cost more to heat the greenhouse than the cost of replacing the plants you are protecting, then do not heat it and replace the plants!

What I like about my system (see here) is its control ability!

Do not buy any heating appliances with a poor thermostat on it!

Cheap thermostats may be only accurate to +/- 5° meaning it might be on when not required, and worse still; off  when it is required 

My stat is accurate to +/- 1° and I only use the heater to keep the general atmosphere above freezing, currently I am holding 4°C (40°F) now that I have lots of plants on the go, during the winter months I had it set for 1°C (3°F)

The best form of heating I find is a 'hotbed' formed with either thermostatically controlled under soil cable or mat.

I can get get 15 standard 350 x 200 (14"x 8")  trays on it, whereas a propagator might only hold two at best!

My set up of a 12 m (40 ft) cable (80-100 watt) and the stat cost around the same as a large propagator to buy, and it uses about a similar amount of electricity but I have six-seven times the heated area!

So I would not count electricity out just on economic reasons, used properly it can work out the cheapest way to heat a greenhouse!

As you can see from my post above I bought this in the end after working out how much everything would cost...



I also have to say I haven't dare used it in the plastic GH as there is a gale blowing through that would keep it going day abd night, whuicgh wasn't 3hat I had in m ind.

I wanted it to give me the extra growing month that the UK has and now that we have bought a "proper" GH I think that, as soon as we have erected it (when we can lay the foundation as the ground is still totally frozen here) I hope that it can just be used mornings and evenings as we are supposed only to be having minus 1/2/3degC instead of our usual double minus figures!!

I will post as soon as I use it for the first time....hope it doesn't explode or something!!

RF

[Tig]

I'm not sure if this is an option - but having spotted it today it does have a few advantages, in that it's cheap and not difficult to source! One consideration would be the carbon monoxide produced and of course the condensation - but any heat will generate some condensation in a cold space. I was thinking of perhaps just using one slightly larger candle, and would definitely use bricks and something inflammable under the loaf tin, maybe another brick.



There are several other videos using slightly different methods on the same theme, the one that uses a screw and bolts would perhaps hold the heat longer, although I had some concerns that the terracotta pots might get too hot and break

[Rosefriend]

Nov 10, 2013 23:30:29 GMT Tig said:

I'm not sure if this is an option - but having spotted it today it does have a few advantages, in that it's cheap and not difficult to source! One consideration would be the carbon monoxide produced and of course the condensation - but any heat will generate some condensation in a cold space. I was thinking of perhaps just using one slightly larger candle, and would definitely use bricks and something inflammable under the loaf tin, maybe another brick.



There are several other videos using slightly different methods on the same theme, the one that uses a screw and bolts would perhaps hold the heat longer, although I had some concerns that the terracotta pots might get too hot and break

I have to admit to not even trying my new heater but will do in the spring...

However some good ideas there Tig and cheap...

RF

[Ladygardener]

I had a look at your link Tig. I would wonder about the little pot cracking or breaking too. I wish I could get those 100 tea lights from IKEA for £1, I pay £1 for 20 at the pound shop.

[Chuckles]

Having looked at the vid I reckon thats a great idea Tig. It would work particularly well in a small GH or if you had a larger one where you had just a small bit sectioned off to keep plants frost free.