Building a Greenhouse

Hi to All, My first post and with the knowledge I`ve resourced from other forums on a range of subjects I`m sure this will be no different. I`ve a new house (self build) and am now starting on the garden with no real previous experience apart from the "odd dabble". With the facilities I have available including time I intend to construct a wooden greenhouse from scratch. I have a well kitted timber workshop so fortunately machinery readily available what isn`t is the knowledge and pitfalls to be aware of. So although a wide ranging subject I`d appreciate any input/advice from you guys.

Regards JD

 

Have you found some plans for one? (I guess they will be available on the internet)

Not a trivial project by the sounds of it ...

I can't help with building a wooden greenhouse (other to to say I think you are quite mad!) but I have views on where to site it, things to think about (rainwater collection etc), and how to "run" it

Bit pushed this morning, but I'll come back and try to put some thoughts together on those points later

 

Before you build it entirely out of timber, have a look at the glass houses in the Victorian Kitchen Garden series,

http://gardenerscorner.co.uk/forum/Thread-Zigs-Garden-countryside-TV-Channel.html

And consider having the North elevation built of brick or block for the thermal mass value. It will warm up during the day and help regulate the temperature.

It won't cool down in a north wind as quick as a glass elevation either.

 

That's saved me writing most of my answer, thanks John!

Water butt at the front = need one either side of the door (but nearer the door to fill the can). At the back = one butt can collect both gutters. Slope the greenhouse slightly to whichever end the gutters should flow.

I have grown in grow-bags and pots (and even straw culture and ring-culture), but now I prefer growing in the greenhouse borders. Watering and feeding is much easier, and doesn't need to be as frequent, nor as regular. Missing a watering with pots / bags is likely to cause split fruit on Tomatoes, and blossom end rot and so on (i.e. nutrient deficiency diseases) need closer monitoring.

But you have to change the soil each year (well, you could perhaps grow grafted disease-resistant Tomatoes etc., but the feeding would still be an issue as the previous crop will have stripped all the nutrients that variety wants).

My greenhosue borders are a mix of well rotted manure and home made compost. I would call it "rough" - not fully composted. By the time it comes out the following year it is nice and fine but importantly its light to work and handle, so the job is not back breaking. But digging out the original heavy clay soil was! and I wish I had done it before errecting the greenhouse, rather than after a whole season being baked by the sun (I grew in pots on the bare earth the first year). Growing in borders also provides more cropping height to the roof (my borders are lowered in the greenhouse to provide even more height).

The vents are important. You need "plenty" - I would say you need a 2' vent for each 4' run of the house, perhaps even more. Mine are on alternate sides of the house, so I can open the side away from the wind more, and I can open the two at opposite corners a crack during the Summer nights.

But if you cannot attend the greenhouse easily they you will need automatic openers.

I favour a lourvre window low down (at the far end, say) so that you can get convection cooling. In the heat of summer you may have to throw the door open to get enough cooling, but the draught stresses the plants more, and its worth trying to avoid that as your "routine" means of cooling other than during exceptional temperatures.

You may want to consider shelving at the rear end - it represents the greatest height, and shelving tends not to get in the way of the various uses the house can be put to.

Also consider if you want staging (pot plants etc) or crops. If staging only you might be happy with brick or timber to staging height, and glass only above that point.