London (change)
Today 20°C / 14°C
Tomorrow 21°C / 15°C
11 messages
31/03/2013 at 23:04

Hi everybody,

I've just ordered a new cedar greenhouse and have the option of a dwarf wall or glass to the ground. Apart from the hassle of building the wall, is it a bad idea to have a dwarf wall on a 6 x 8 lean to? Will it cut out too much light? I have thought of raisng the internal floor level and then placing plants like tomatoes in large pots. Does the insulation benefit justify a dwarf wall?

01/04/2013 at 09:24

I used to have one in my old garden which was glass to the floor. I think they're less robust than the ones with a dwarf wall around. Depending on where you are, what aspect your GH has, and what you're growing I think a wall around the bottom is likely to protect plants - esp. the roots - better from frost than glass to the ground. However, if light is limited then glass all round may be the answer

 

01/04/2013 at 12:14

Thanks guys, I suppose you're confirming what i suspected, that there is no easy answer. I want maximum light but as I live over 1000 feet up above the south wales valleys the weather can be extremely hostile so I was thinking about the wall. The GH will be south facing however the dwarf wall would have to be about 2.5 feet with the front of the GH only 5 feet in total. I think I need to make a decision.

01/04/2013 at 13:15

Do you need to use a mower/strimmer near this lean to?  If you do there is always a risk of a stone being thrown up which could break the glass if it goes to ground level.

01/04/2013 at 14:07

Hi gurbian, you mentioned it was a lean-to type and that it's South-facing.  Are you erecting it on the side of your house or other existing wall?  If so, the wall will act as a thermal mass, absorbing heat during the day and releasing it at night, doing the same job as a dwarf wall but better, so I would personally choose glass-to-ground and maximise light.

01/04/2013 at 14:07

Would the bricks provide thermal heat mass? I would think it should help particularly on the northern side. I would have thought you would get a better balanced temperature with the bricks.  

01/04/2013 at 14:31

I have a lean-to green house south facing the brick wall being to the north side. Even with minimum sun that wall takes in heat and gives it back at night, the green house went below freezing for the first time this year and it has been up nearly thirty.
I had a one foot high base wall on the south side as I have gravel beds and glass would have been a problem right to ground level.
You will find your dwarf wall will also take in heat and give it back, will stop accidents with ground level glass and some pots need shade so the wall provides it. Tomato pots behind a wall will stay moist yet the plants get all the light they want so to sum up more ticks for a wall than against, I would have it.
One more thought if you wanted a raised bed in the greenhouse, you already have three sides some wood boarding on the front side and fill it with soil, one raised bed for tomato's or anything you wish, just remember to change some of the soil each future year.

Frank.

01/04/2013 at 15:10

This is my current very cold and draughty lean to, against the garage wall. The garage wall doesn't hold a lot of heat but it will when its repainted. The new on will be in the same spot but 6 foot wide instead of 4

http://s4.gardenersworld.com/uploads/images/original/20818.jpg?width=305&height=350&mode=max

 

01/04/2013 at 15:24

I take it the new GH will cover the window, will that matter.
White deflects the light yet painting a warmer colour will look odd.
Mine is simply brick so takes in the heat and holds it.
You have plants along the base anyway so a wall would make a good place for pots with probably some cover like a cold frame.
I have to watch the airing of my South facer with extra vents and a fan for frost guard and cooling, easy if you can get electricity as you obviously can.
I would go for the dwarf wall.
Good luck

Frank.

01/04/2013 at 21:59

If I paint the garage a nice strong terracotta I could have Tuscany in the valleys, but maybe not quite as warm. So dwarf wall it is. Now I just have to dismantle the exsisting GH and build a wall. Its so cold that all my plants and seedlings are currently in the spare bedroom, so the way the weather is at the moment i probably wont need the GH until June.

01/04/2013 at 23:27

Cement does not set well in cold weather could be best to leave a week, it will warm up, here in the frigid North we have had four days of sun, freezing easterly winds though.
Terracotta should hold the heat in the bricks and feed it back so worth a try.
Good luck send a picture when done.

Frank.

email image
11 messages