How to heat my greenhouse

For the discussion of topics related to the conservation, cultivation, propagation and exhibition of cacti & other succulents.
Forum rules
For the discussion of topics related to the conservation, cultivation, propagation, exhibition & science of cacti & other succulents only.

Please respect all forum members opinions and if you can't make a civil reply, don't reply!
cactusnicky
Registered Guest
Posts: 5
https://www.behance.net/kuchnie-warszawa
Joined: 05 Sep 2010
Branch: BRIGHTON, HOVE & District
Country: uk

How to heat my greenhouse

Post by cactusnicky »

Hi people
I'm after some advice please. I have a 8ft x 8ft greenhouse, it is bubble wrapped and I have cerei and echinopsis and some agave in it. I do have electric sockets in there, but what type of heating would members recomend ?
TIA
Nicky
Ross M
BCSS Member
Posts: 1791
Joined: 15 Jun 2008
Branch: None
Country: Scotland
Role within the BCSS: Member

Re: How to heat my greenhouse

Post by Ross M »

An electric heater would probably be the best Nicky. Clean, reliable and easy to set. Something like this would do the trick - http://www.greenhousepeople.co.uk/acces ... ntana_2kw/

There's lots on the market to choose from. Also a good idea to invest on a decent digital min/max thermometer - check eBay.

You don't need to set it to anything higher than 5C, although 2C would be more than enough for your Echinopsis, which tend to be pretty hardy anyway and can usually withstand frost. Insulating does definitely help as well as saving on heating costs. If the plants are still alive and well after the past months cold weather, they'll probably survive the rest of the winter without heat. Just remember to keep them dry and cover them with a sheet of newspaper on the coldest nights.

Heating a greenhouse ain't cheap these days, even the smaller ones so hardy plants are often the way to go :wink:

Hope this helps.
Ross

Dunbar, SE Scotland.
BCSS member #46264 (originally joined 1983).
Growing cacti since 1978, with a particular interest in Sulcorebutia and Rebutia.

cactusnicky
Registered Guest
Posts: 5
Joined: 05 Sep 2010
Branch: BRIGHTON, HOVE & District
Country: uk

Re: How to heat my greenhouse

Post by cactusnicky »

Thank you Ross, I will have a good look on the internet and also the web site that you suguested
Nicky
User avatar
Dave_S
BCSS Member
Posts: 204
Joined: 02 Jul 2009
Branch: None
Country: England
Location: Midlands

Re: How to heat my greenhouse

Post by Dave_S »

Nicky,

I agree totally with Ross, electric heater especially as you have the electric supply already in your greenhouse. I have a parwin heater, purchased last year, unfortunately they have stopped making new ones now :sad: . My Echinopsis and Tricho hybrids are fine with a minimum temp of about 7c, maybe they could go lower, but there are some expensive ones so don't want to risk losing them :smile: .

Best wishes

Dave
Lithops cultivars and Conophytums...Admin for Lithops U.K. on Facebook
A member of the MSG and the Echinopsis Hybrid Swap Circle (find us on Facebook)


AVATAR: Lithops verruculosa 'Rose of Texas'
Torbjorn
BCSS Member
Posts: 273
Joined: 19 Nov 2008
Branch: None
Country: SWEDEN
Role within the BCSS: Member
Location: Stockholm, Sweden

Re: How to heat my greenhouse

Post by Torbjorn »

Hello,
At least in the Swedish climate, one heater fan might need to operate at a power close to the fuse rating.
To avoid this I have installed two separately fused outlets, and use two lower Wattage heater fans. In my case this is 750W, or 1000 W on each 2400W (10A) outlet.
They also has their own separate thermostat.
My greenhouse is about 1 hour by car away from my winter home, so I have to be extra careful.
I also have a lamp always lit in the greenhouse, so that the neighbors are alerted, should there be a power failure.
Good luck
Torbjörn
Stockholm, Sweden
User avatar
iann
BCSS Member
Posts: 14562
Joined: 11 Jan 2007
Branch: MACCLESFIELD & EAST CHESHIRE
Country: UK
Role within the BCSS: Member

Re: How to heat my greenhouse

Post by iann »

A 1kW heater will easily keep your greenhouse frost free., but to keep it at 5C you might need more than 2kW. It all depends how warm you want it. Not very if you haven't had heating so far this winter!

There are online calculators but they can only be approximate. 1kW/2kW switchable heaters are cheap and easy to find but the thermostats are not the best. Also, many thermostats either aren't very accurate below zero or simply don't go that low. You might want to experiment and then see if you need to buy a separate thermostat.
Cheshire, UK
User avatar
Pete A
Posts: 556
Joined: 17 Dec 2009
Branch: READING & BASINGSTOKE
Country: UK
Role within the BCSS: Committee member
Location: Yateley, Hampshire

Re: How to heat my greenhouse

Post by Pete A »

Here's a handy "heat needed" calculator. Interestingly, it shows roughly 40% less heat needed for my greenhouse if bubble-wrapped. I took my bubble-wrap down for last winter as it was disintegrating and my gut feeling was that it cost a LOT more to run and the temperature swings were more pronounced. The calculator appears to back my gut feeling. I think that bubble-wrap would pay for itself within one to two winters.

Heat Calculator
Zone 8 Representative (Birmingham, High Wycombe, Kingston-on-Thames, Oxford, Reading & Basingstoke, Woking).
David Robson
Registered Guest
Posts: 147
Joined: 24 Sep 2009

Re: How to heat my greenhouse

Post by David Robson »

cactusnicky wrote:Hi people
I'm after some advice please. I have a 8ft x 8ft greenhouse, it is bubble wrapped and I have cerei and echinopsis and some agave in it. I do have electric sockets in there, but what type of heating would members recomend ?
TIA
Nicky
hi cactusnicky,i do not heat any of my greenhouses, any thing that i believe is at risk, i bring in doors in rooms that are kept on the cold side.i have echinopsis in a coldframe in the garden, i looked the other day , and all was well.in the greenhouse i lay the bubblewrap over the plants, i do not pin it to the frame. this time of year it can stay on for the next 10 weeks i expect .when the sun does shine strongly i will take it off. i have agave outside all last winter,to no effect.like many growers have found it is just to expensive, i wasted a lot of money in the past on heating my greenhouses , and most of the plants would have survived anyway david
User avatar
Diane
BCSS Member
Posts: 5574
Joined: 15 Jun 2007
Branch: None
Country: UK
Role within the BCSS: Member

Re: How to heat my greenhouse

Post by Diane »

Hi Nicky, I think the heater that Ross linked to will be fine for you - I have an old Jemp heater very similar to this, which I use in my 16' x 6' greenhouse which is adequate to keep frost free, and the digi thermometer on the same page for £6 is excellent too.
Diane - member of Kingston branch

Growing cacti - balm to the soul!
User avatar
LithopsRule
BCSS Member
Posts: 177
Joined: 14 Dec 2008
Branch: MACCLESFIELD & EAST CHESHIRE
Country: UK
Role within the BCSS: Member
Location: Macclesfield, Cheshire, UK

Re: How to heat my greenhouse

Post by LithopsRule »

That online calculator PeteA found at Jungleseeds is very useful! (tu)

I am hoping to obtain an 8' x 12' glass greenhouse in the spring, and the current weather was making me wonder about how I would cope with weather going down to -10degC next winter. :shock:

Knowing from the calculator roughly how many kW would be required is very handy for me, since I do not really want to be conducting experiments "blind" when there are plants to be damaged if I get it wrong!

It is also nice to know that the approximate heat-loss factor is roughly HALVED on going from a glass greenhouse to one lined with polythene sheeting (I know it depends upon how exactly you do it, etc., but the order-of-magnitude is nice to have in one's mind).

My own recent "forced experiment" with Lophophora williamsii (no room left in the house...!) was illuminating: in just an un-heated aluminium cold frame raised 3' on aluminium legs, I lost ~50% of my test plants (min. -10degC); but the ones additionally enclosed in a plastic propagator (min. -6degC) sufferred no losses at all (n ~ 30 in both cases).

Is there any table available detailing genuine measured cold-hardiness of cacti and succulents?
Euan Arnott (Cheshire, UK)

Novice grower renewing his teenage enthusiasm. Rapidly burgeoning Lithops, Lophophora, and Ferocactus populations, plus a few old stalwarts which have acompanied me through the years!
Post Reply