Shade/glass house

[Kees Green]

Hi
This has probably been discussed lots of times.
But does anyone have any plans or ideas for building a house to grow bulbs, in particular narcissus and reticulate irises.
They do grow outside well here in NZ but I would like some ideas please, I have seen the pics of Ian's houses and they appear to have glass and open sides I think.
Any ideas will be greatly appreciated, thanks.

[PDJ]

A good idea would be to describe the area you live in, rainfall, seasonal temperatures etc.  The thread 'Frost Damage' for example gives an idea of how variable a glass house contruction needs to be according to regional weather conditions.

[Lesley Cox]

Hello Kees, my climate is certainly drier than yours by about 20 inches of rain a year but I agree a glasshouse would be a useful addition for some things. When I get round to it, mine will have just a cover over the top and open sides, perhaps with plastic that can be let down in very frosy/snowy weather. But I want mine for onco and regelia irises and some very dry-loving alpines, rather than narcissus and retics which grow better for me in the garden then in pots. In my opinon, maximum ventilation is vital. A nursery friend near Gore has plants under glass with the sun pouring through and heating them well but there are many panes left out and the house itself doesn't seem to me, to be very hot (I've not been in it in high summer though) but is a great protection from rain when bulbs/rhizomes are ripening.

[Kees Green]

Hi
Thanks Leslie. I think that I will use clear PVC or similiar and perhaps mesh and alternate them on the sides as this will allow air movement and the clear roof.
I was a bit confused by the "shade" part, can not see why I would need shade given our mild climate.
Thanks again

[Diane Clement]

I was a bit confused by the "shade" part, can not see why I would need shade given our mild climate.
Thanks again   

It depends what you intend growing.  I don't shade in the autumn through to spring because the things in active growth are bulbs, cyclamen and hepaticas, which all need full light at that point.  It also depends on the aspect of your greenhouse.  Early in May the sun is high enough and striking the glass of my greenhouses for long enough each day to cause severe damage so I find shading is necessary from then onwards. 
So although we do have a very mild climate, we do use shade on all four greenhouses and two frames from May to September. A few hours on a sunny day can cause scorching to plants, even those from much warmer climates from ours, just because of the microclimate inside the greenhouse due to the "greenhouse effect".  All my greenhouses have a lot of ventilation, but it's not enough at certain times of year. 

[Lesley Cox]

What I think of as a "shade" house is covered with a shading or windbreak cloth (PVC) or even better, made from 1 1/2 or 2" timber laths which lets all the air flow through and gives a moving shade as the sun travels west, as would be the case with light, dappled shade from trees. I would use such a house for shade-loving plants, and if it were big enough, I'd make a whole garden inside it, with path etc but at the least, benches for potted plants. I think that except for summer-ripening plants such as onco irises (or junos), Cyc. rholfsianum, some Narcissus or other species which like to be entirely dry for an extended period, we in NZ would always need some overhead and north side shading in the summer and into autumn, and covering to protect herbaceous plants from excessive heat.

[Rogan]

I have been experimenting with a "collapsible" design of shadehouse where pipes "plug in" to the joints and are held in place by diagonal wires tensioned by turnbuckles. I use 32mm galvanized piping (...what we call "gate and fence tubing") with a 2mm wall thickness. From bits and pieces the whole structure, 3 metres x 6 metres, goes up in half an hour flat - it can then be covered with shade cloth or poly-tunnel plastic, or even wire mesh for birds     Unfortunately you will need a fairly well equipped home workshop or a sympathetic handyman to help you manufacture the joints. I will post some photographs of my prototype soon   

[Paul T]

Kees,

An enclosed glasshouse here in winter could easily hit well over 30'C on a sunny day, despite it only being 15'C outside.  The shade certainly does help it stay a bit cooler.  You can only imagine what temperature it would be here in summer if fully enclosed with no shading.  

[Lesley Cox]

Close to 60C Paul. Some years ago when I had plants in quarantine in what had to be an enclosed structure with no ventilation because of the possible entrance/exit of insects etc, I complained to MAF and was eventually allowed to substitute the plastic cover for a very fine mesh (double thickness) just 1mm gauge. If I hadn't shaded as well I would have lost the lot, but the shading couldn't be too heavy because light was needed too.