Cold Greenhouse

[Bal]

I have raised tomato, aubergine and chilli plants at home.The tomatoes are about six inches tall,the aubergines about five and the chillies about four inches tall.
I have a glass greenhouse at the allotment without any heating.Can I now plant the the above in the cold greenhouse?
Has anyone done this with success.I am in Essex
Your help will be greatly appreciated.

[alan refail]

Can you guarantee that Essex will remain frost-free for the next six weeks or so. If you could provide heat, less of a problem.

Alan

[Compo]

I am not sure where this idea that greenhouses are not protected from frost, if you leave it all buttoned up at night, It has to be a minus 6c or 7c frost to lower the temp that much inside, and we did not get that in the winter in the south so not sure we will get it in the spring. I think all tender plants should now be safe in unheated greenhouses and if frost is forecast, you could protect em with some fleece, straw or newspaper or similar....


Compo

[Tigger]

I'm with you Compo - I've got all my tomatoes, cucmbers, aubergines, melons, peppers and chillies in unheated tunnels. I do have a frostguard heater in each, set to fire off if something happens, but it hasn't triggered since the cold week we had in Feb.

[Colin_M]

Good to hear chaps. I'm in exactly the same position as the original poster.

I do have a frostguard heater in each, set to fire off if something happens

Can you tell me a bit more about this. I assume it's electric.


Colin

[Tigger]

Yes - electric. The ones we use are Dimplex Coldwatch. They have a range of settings, so you can set them to maintain a particular temperature, or you can set them to come on if the temperature drops below a certain level.

We first bought one when we had our (current) dog. Our previous dog always slept in the barn with the cats, so making sure she was warm wasn't a problem. When we got our Brittany, we decided to use a cage for her to sleep in, in Lyndon's spray room in the barn. We tried using an electric fan as a method of heating, but it dried her eyes out. The electrical supplies shop suggested the Coldwatch, which works brilliantly. We set that at a maintenance temperature.

When we put the tunnels up, we thought we'd start with these as a means of keeping the frost away and see how they performed. I use these on a frostguard setting.

There's no significant difference between our winter and summer electricity bills, so they're not particularly thirsty.

[Allan]

The experts generally state that if tomato plants go below 10C. at any time it can affect the plants' ability to crop, a frotguard heater setting would not meet this requirement. I am inclined to meet this requirement if possible, otherwise you will obviously get some sort of crop anyway, probably sufficient for vyour vrequirements.
Allan

[Compo]

The point Bal was making was that he does not have power for such luxuries as your frostguard heaters, so his best bet like me is to watch the weather, be armed with fleece etc and hope for the best!!

Compo

[alan refail]

The thought that was in my mind when I posted my initial comment was the one that Allan makes - obviously frost will kill all the plants, but none of them will thrive if the temperature is too low, even if above freezing.
I did not want to be negative and make the obvious comment that it seems far too early to plant in a cold greenhouse. I can appreciate the desire for early crops, but a slightly later crop is far better that a lost one. The commonest sight at this time of year among fellow plotholders, when I had allotments, was the blue tomato in the cold greenhouse. I'm sure they would have been surprised that Compo's greenhouse is OK with outside temperatures of minus 6-7C.

Alan

[Johnboy]

Hi Alan,
I feel that the problem lies in sowing too early.
This seems to be a theme running through the forum at this time every year.
There is a joke about the young bull and the old bull, which no doubt some people are familiar with. Now I do not propose to publish this joke but for those familiar, the same applies to the sowing of plant seed!
JB.

[Allan]

JB
Quite right. Do you remember where we both got the info about minimum temperature from,I think it might have been in The Grower for me.Too many people sow far too early, it is surprising how the later sowings catch up. I sowed about mid-March, even that might have been a little precocious but I do have a very large heated propogator. I notice that some of my tomatoes that looked fine 2 days ago are starting to go leggy so they will be moved to the farm greenhouse where there is nothing shading it. There is thermostatically controlled gas heating and automatic ventilation, I sorted out the automatic watering yesterday. I have approx 150 Gardeners Delight, various makes, hoping to sell a lot of plants.Supersweet 100 all got sunscorch, had to re-sow, a pity as they are always slow to fruit.

[Mike Vogel]

What I am doing at present is to cover all my cold greenhouse plants with bubble-wrap in the evenings. This double-insulates them. I would hazard that if you could do this each evening, Bal, you would get away with it at this time of year, when the length of frosty nights is less. The key thing is that the veg are in shelter inside their greenhouse.

I am already moving my tomatoes out of the greenhouse into one of those Focus Multigrow things and not coveringthem up any longer, because they are able to tolerate some degree of cold, but I would take more care with the peppers and especially with the aubergines. Lucky you - my aubergines are only 2 inches high at the moment.

mike

[Primrose]

I transplanted my peppers and aubergines into their final pots several days ago, when they were six inches high, and put them outdoors in my mini greenhouse with its plastic cover. Admittedly the nights have todate been quite warm, but I intend to leave them there now, and if necessary put a layer of fleece over them at night if a cold spell is forecast.

[Colin_M]

From the above posts, it seems clear there's a difference between :
- a plant's ability to survive frosts, and
- the effect that less extreme cold can have on plant's ability to produce fruit later on

So far we've mainly discussed Toms. However I have some aubergines, peppers and (gulp) okra at stake too.

Would anyone care to advise on sensible minimum temperatures (eg. the 10 degree C one for Tomatoes to still fruit successfully) for other common plant species?

Maybe it could be added to the Technical section (once we've all had a good argument about it ).


Colin

[Johnboy]

Hi Colin,
I would suggest that a minimum of 10C for all the plants you mention. I am not for one moment saying that below that temperature they will die but they certainly benefit for not going below 10C especially Tomatoes.
JB.