Do I need a greenhouse heater?

freebo_2

***Sorry if this is a stupid question***

All,
I'm looking to grow veggies for the first time this year (apart from windowsill chilli crops for the last couple of years) and am about to order my first greenhouse.
I'm looking at tomato seeds and the instructions say things like "january/March sow in greenhouse at 18C". Does this mean I need to maintain a temp of 18C constantly in the greenhouse Surely to do this during Jan/March a heater would be required.

Next question is what kind of heater? Currently there is no power source near the greenhouse site, although I may have one installed.

Lastly, other than tomatoes what else should I look to grow under glass, legal answers only

Thanks!

Mike

Jazzy_B

I don't heat my greenhouse, so i can't give you any advice about that really. I did look into it but I didn't think it was worth the cost. Our only option was paraffin heaters which I didn't fancy.
I do grow tomatoes which I start off indoors in a small pot on a sunny windowsill around the end of February. When I transplant them, I usually keep them indoors for a week or two, but as soon as i think it's ok , I put them in the greenhouse on polystyrene packing. If I think it's going to freeze I cover them in bubble wrap overnight.
I start off potatoes in a huge tub in the greenhouse, and also salad leaves throughout the winter.
I should use it more, but as I spend most of my time in there from March onwards, I enjoy the break.

There's also very little room left, as I overwinter loads of things like geraniums.

All the best with all your crops.

MaureenHB

Although I don't think it's a necessity if you have a sunny windowsill or two I am looking into prices for a propane gas heater for mine , as we are keen gardeners and we have just moved house to a garden with a lovely old wooden 12 foot by 10 greenhouse. Itching to get going!! I find the electric windowsill propagators are wonderful .. I have one with 7 compartments and seeds just thrive.

jennifernil

Heating a greenhouse is expensive and not really worth it unless you really fill it up and grow loads of stuff.
You could, if you had power available, use a soil warming cable on the greenhouse bench, suitably insulated, or a warming mat, or a heated aluminium warming slab. Take a look in the Two Wests and Elliott catalogue for ideas. You can get a small electric propagator to start things inside then transfer them to the heated bench in the greenhouse. Covering with fleece at night helps keep the heat in.
If you don't want to invest in so much equipment then just start your seeds later, as the weather gets better they will catch up a bit , but you will be later in getting the fruit. A small propagator is still a good idea to get things started.
Sow your seeds in cells, we use the ones that have 50 cells that fit in a seed tray, they can be cut into strips of 10. That way you have no pricking out, just move them to a 3" pot when they are big enough, then either plant out or move to final large size pots. For bigger things like courgettes use larger cells.
We have 2 heated GHs 8x10 and several cold frames. We used to grow up to 20000 plants per year which we sell for charity, now winding down to retirement so only doing 7500 this year! With that many plants you need to use all the shortcuts. To heat the 2 GHs from Feb to April costs about £200. We are in central Scotland.
Other things to try are sweet peppers, aubergines, melons, cucumbers, courgettes, herbs, lettuce, bedding plants and other veg that you start inside and plant out later.
If you do decide to get a heater I would go for electric, the other types can produce a lot of water vapour and lead to plant diseases and fungal infections such as damping off etc.