glasshouse questions

sunnyday1234

Hi Everyone
I am interested in getting a small greenhouse / glasshouse about 6ft x 8 or something, just a place where i can grow some fruit and flowers as a hobby
My problem is that my entire back yard is tarmac
Can i put a greenhouse on this ? Obviously i wont have soil in the ground so i will have to use pots and growbags etc but is there any other reason why i couldnt do this ?
Thanks

Marhay70

sunnyday1234 wrote: »

Hi Everyone
I am interested in getting a small greenhouse / glasshouse about 6ft x 8 or something, just a place where i can grow some fruit and flowers as a hobby
My problem is that my entire back yard is tarmac
Can i put a greenhouse on this ? Obviously i wont have soil in the ground so i will have to use pots and growbags etc but is there any other reason why i couldnt do this ?
Thanks

No reason why you can't put your greenhouse on tarmac provided it is reasonably level, you will probably need an aluminium base as well.
Mine is mounted on concrete and I use it for growing early potatoes, carrots, tomatoes etc. I also use it for raising flowering plants, both hardy and half hardy annuals from seed, I grow them in modules, and for cuttings. I actually prefer to grow in pots as there is less chance of fungal and other diseases.
The only reservation I would have about tarmac is shading in summer. If the greenhouse is not shaded, temperatures can easily reach 40-50 degrees celsius on warm sunny days and you could find yourself stuck to the floor:).

sunnyday1234

ok thanks

you mean the tarmac could melt ? so would it be better in shade then, what about lack of sun then ?

why the need for an aluminium base ?

Marhay70

sunnyday1234 wrote: »

ok thanks

you mean the tarmac could melt ? so would it be better in shade then, what about lack of sun then ?

why the need for an aluminium base ?

No, between about mid March and mid September you should shade the greenhouse itself with netting as temperatures can get very high and this is liable to kill any seedlings you have, even mature plants. You can buy netting in most garden centres and some of the DIY chains, you need special clips which hold the netting into the frame struts.
Tarmac today doesn't melt as readily as years back but with the temperatures in an unshaded greenhouse, it's very possible. You will need some sort of rigid base to stop the greenhouse frame from moving about, you can use timber or concrete blocks either but the bespoke one is handier.

sunnyday1234

great thanks
and would a 6 x 8 one be strong enough not to move with strong winds ?

Marhay70

sunnyday1234 wrote: »

great thanks
and would a 6 x 8 one be strong enough not to move with strong winds ?

I think you misunderstand,when I say move I mean the frame not staying square. Any greenhouse is vulnerable to strong winds if you fail to take precautions such as keeping doors and vents closed when wind is forecast and sealing any gaps and it can be better to erect it broadside on to the prevailing wind so as the slant of the roof will deflect the wind upwards, it only takes one pane to blow out for the whole lot to be wrecked. Strange as it may seem, garden walls can play havoc with greenhouses as they create turbulence on the leeward side, picket fencing or hedging is much better as they act as a filter. It really is a case of what the layout of your location is but no greenhouse is safe all the time. It is important that it is secured to its base as if it lifts it will just keep tumbling.
A rule of thumb with choosing a greenhouse is always to choose the next size up from the one you think you need.

macraignil

sunnyday1234 wrote: »

great thanks
and would a 6 x 8 one be strong enough not to move with strong winds ?

It would depend as well on the design of green house you buy. I got one that size off e-bay a few years back and the flimsy sliding door design meant it did not last very long. Once the door had been blown off and damaged so it could not fit back into place the rest of the frame fell apart soon after.

sunnyday1234

can anyone recommend a good place to buy a greenhouse? 

From the posts above , i just want to confirm that i would not be anchoring the base  to the tarmac, just laying it on it. would this be ok ?

baaba maal

You definitely need to anchor a 6x8 to the ground- it will definitely get destroyed in a winter storm otherwise.

sunnyday1234

ok thanks. here lies hte problem for me so. i dont want to anchor the base into my tarmac cos it would wreck it

baaba maal

Maybe fix two solid blocks together for each corner and bolt/tie the Gh frame to the blocks? you lose the footprint of four blocks from the floor area but it would probably* hold.

*Not a legal opinion, just an opinion!

Marhay70

Build a base of solid concrete blocks and anchor the frame to it with screws and rawlplugs, no need to buy a separate aluminium base then. You can just lay the blocks flat if you're not a competent diy-er, no need even for mortar that way although it would be a better job. Just make sure the frame of the greenhouse is square. You will have to cut some of the blocks but that's simple enough with a cold chisel or bolster.

sunnyday1234

so i like the idea of the house attached to the blocks with no mortar. this has the benfit of also being movable if i needed. 

so im thinking of getting something like this,

http://www.adverts.ie/other/greenhouse-8ft-x-6ft/11173766#comment_80389465

i know its small etc but i want to start very small and see if get on ok

I really just want a hobby where i can grow things like tomatoes / chillis and other exotic stuff . The ammounts would be really small but would just be a nice hobby

This is all achievable, correct ?

baaba maal

Perfectly good greenhouse think- polycarbonate is considerably lighter than glass (I have toughened glass in my greenhouse and I would say that the glass is about 70% of the total weight) so back to the original issue about making sure it is well secured. I would also say that the ad could give the impression that the greenhouse is insulated "and will be a great solution for protecting your plants from the cold weather"- I wouldn't think it would offer much protection from the cold (although it would keep heavy frost off some outdoor shrubs in pots over winter}.
If you can stretch to it, you could rig a water butt up to the guttering, just make sure you raise the greenhouse slightly at one end and the other end of the gutter is the end you connect the water butt to.

Marhay70

Polycarbonate is a much safer option if you have kids or pets but can be a problem if it's a very windy site as the sheets can flex and pop out, my advice would be to buy extra glazing clips and use at least double the amount recommended in the instructions. Polycarbonate also has the tendency to discolour over time, so reducing light levels but it should probably be ok for raising plants from seed or cuttings. Once again I would stress the need to make sure the frame is square on all aspects.

sunnyday1234

sorry guys. can ye check out this last one for me please ?
https://www.lenehans.ie/eden-burford-greenhouses.html
I am looking at the 6 x 8 one , aluminium with the toughened safety glass. Its coming in at 791 with a free water but and connecting kit. 

so its 300 extra but comes with the water but which is maybe 50 euro ? If i got the one with toughened glass then would it be ok not to anchor the house to concrete blocks ?

I guess i could get the 429 polycarbonate one and get a few years out of it and see how i get on and upgrade down the road if i really get into it

I know its not insulated but all i want is to grow a few exotic things like chilli / red peppers etc in very small ammounts just as a hobby. I presume either of these houses will suffice for this ?

baaba maal

Yes, either will do for that. I would have to say that anyone I know (including myself) that gets a green house ends up for using it for more things than they intended. I bought a €2.99 Lidl grapevine two years ago, planted it in the greenhouse and got four rather nice bunches of grapes last summer! All I'm saying is.... things happen when you get a greenhouse:D
The one structural weakpoint on the Burford for me, is that there is no bracing at the front- my greenhouse has a :lip: at the door. This is a rigid piece of aluminium that goes corner to corner, so completing a solid rectangular base. Only a minor point but worth considering when securing it to blocks etc.
My personal preference (if I could stretch to the extra €150 or so) would be to get it in green- I think it looks really well in green. I only say it now as I have heard people mention that they bought one in brushed aluminium, then decided after to paint it using special aluminium paint, but that the paint did flake. The green option is powder-coated so will last for ever (relatively speaking) maintenance-free.

sunnyday1234

if i got the toughened glass, would i still need to secure it to something ?

Marhay70

sunnyday1234 wrote: »

if i got the toughened glass, would i still need to secure it to something ?

Although it is stronger than standard horticultural glass, toughened glass is still liable to break if the impact is sufficient, for instance if you are mowing grass nearby and a stone is flung out. The real benefit is that when it breaks it doesn't break into large sharp pieces but into small bits, like a car windscreen. Some people have attached self adhesive clear plastic film to horticultural glass to mimic the properties of toughened glass as the cost of replacing toughened glass can be prohibitive.
You have not given any indication of what your site is like, whether it is prone to strong winds or not but in any case all greenhouses will need a base, this is primarily to keep the frame square. If the frame goes off square, pressure is put on the glazing and panes can just pop out leaving the whole structure vulnerable to the elements.
Like all aspects of gardening nine tenths of success is achieved by preparation, if you go half arsed at something then you can expect half arsed results.

sunnyday1234

site is all tarmac and 99% level. The general area would be fairly windy but the winds hitting the GH would be broken (by a shed in one direction, our house in another and then fences). I would always have the bins in this same area and they are never overturned by a storm so i supposed this is in an indicator of the wind strength
I have decided on this one here
https://www.lenehans.ie/popular-range-of-greenhouses.html#product_tabs_description_tabbed

I am going to lay a foundation of slabs  / flags and place GH on top and secured at the corners using screws into the flags. This should stop it moving.

Marhay70

sunnyday1234 wrote: »

site is all tarmac and 99% level. The general area would be fairly windy but the winds hitting the GH would be broken (by a shed in one direction, our house in another and then fences). I would always have the bins in this same area and they are never overturned by a storm so i supposed this is in an indicator of the wind strength
I have decided on this one here
https://www.lenehans.ie/popular-range-of-greenhouses.html#product_tabs_description_tabbed

I am going to lay a foundation of slabs  / flags and place GH on top and secured at the corners using screws into the flags. This should stop it moving.

Looks reasonable, the fact that it comes with a free base is a bonus as these can be pricey. Lenehans are a good company to deal with too.
The base should come with pre drilled holes to allow you to attach the frame, some also come with pre drilled holes in the base to allow you to attach the base to concrete, others come with ground anchors which are designed to be concreted into soil, it's pot luck. The fact that this one comes with a sliding door means it will be important that the base is level, otherwise the door may stick and be hard to open and close. Make sure you site the vent on the side opposite to the prevailing wind.
You may discover very quickly that you don't have enough floor space and will need to get shelving or staging. The bespoke type also comes with a hefty price tag so it might be a good idea to try and strike a deal with Lenehans when you're buying the house itself. Of course you can always knock something together yourself.
Good luck with it and let us know how you get on.