Author Topic: Greenhouse - slabs v soil? (Read 6393 times)

Izzy · « **on:** May 21, 2015, 06:53:17 pm »

I have been offered a free greenhouse plus help with dismantling/transportation. I've read that many people who've tried this recommend that buying a brand new one is less painful in the long run if not cheaper. But I'm going for it so now need to think about the base.

Discussions online seem to agree that slabs are better than a soil floor. What are TASers views?

bloomer · « **Reply #1 on:** May 21, 2015, 09:15:12 pm »

Slabs or if budget is tight gravel over membrane. Keeps your feet driving your options open.

doganjo · « **Reply #2 on:** May 21, 2015, 09:36:46 pm »

Mine is on slabs. Brand new and a nightmare to put together - bits all look similar on a sheet of paper

Even worse if you try to do it in a high wind!

But it's dry underfoot and no slugs

Fleecewife · « **Reply #3 on:** May 21, 2015, 10:07:45 pm »

We started off growing in the soil in the greenhouse. Now we have benches for young plants, and membrane on the floor as thistles grew under the benches and were hell to get to. We don't grow anything directly in the soil any more. The benches (homemade to fit) bring the plants up to the light.

The base for the walls of the greenhouse is made of hefty balks of wood, like sleepers. Our previous one was on a brick foundation for the walls.

If you want to overwinter any growing chicks or ducklings in there, then have slabs - we found RATS coming up from below and dragging our chicks off. Thank goodness for terriers

Have fun

pgkevet · « **Reply #4 on:** May 21, 2015, 10:32:55 pm »

My first greenhouse was on ground anchors with a membrane floor and that worked fine. Currently my larger one is on a decent ring foundation and two brick high base with side beds and a loose laid central walkay of slabs on sharp sand, sides of that loose laid breeze blocks to slightly raise the beds. It works really well. The original greenhouse gt moved here with twinwall polyacrb insulation and is on a concrete base as my citrus house. it;s actually a nuisance with zero drainage and i had to drill some holes through the base.

Izzy · « **Reply #5 on:** May 23, 2015, 04:25:23 pm »

Thank you for all your replies. Slabs it is then.

cloddopper · « **Reply #6 on:** May 23, 2015, 10:52:12 pm »

Slabs , make the slab base at least 150 mm bigger than the glasshouse and if possible ensure it is raised up above the mean ground level so that if you do get it wet inside it can drain off easily .

Anchoring it to the ground to stop it getting blown away .
Gently drilling the slabs and using chemical anchor bolts ( which make a stress free anchor) to hold it down to the slabs is useful but will cost you about £15 .
I couldn't get my glasshouse insured against storm damage unless I could show the insurers photographs of the anchoring being done and after it was completed .That storm damage clause also included having branches blown down not just the glasshouse being blown away or damaged by strong winds blowing dust bins into it etc.
No anchoring = no claim whatsoever .

Getting the base level /true is very very important , if it is out, like our " Professionally " erected Eden glasshouse . Rain will tend to seek a way in if the glasss is not square in the channels . In the cooler weather this water on the floor can easily lead to tomato blight and other unwanted diseases in the glasshouse . In winter it will like as not kill off anything that you have overwintering ,such as making mouldy geraniums .

My professionally erected glasshouse was 38 mm out of true across the diagonals levels when Alison & I checked it last year . We had to undo all the clamping bolts and slip spades under the lowest edges to bring them level ( used a water gauge to get it all set up ) & pack them up with strips cut off a 10 mm thick red chopping board and strips of a 3 mm thick white chopping board ..
Then we had to put a fillet of mortar all round the inside and outside save for the lowest corner of the cast concrete slab as this low point makes a handy drain point for when we do the annual scrub out & disinfection.

Lesley Silvester · « **Reply #7 on:** May 26, 2015, 12:55:09 am »

When we moved here, the greenhouse was an plus. It's built on good solid foundations and had gravel over plastic (very thin plastic) with a slab resting on bricks path. After growing tomatoes in pots the first year, I got rid of the gravel and plastic, only to find there was rubble underneath so that had to go. I now plant straight into the soil and much prefer it. The plants seem to as well and if we have a lot of rain, I don't even need to water every day as they take it up through the soil.

I know I'm outnumbered here, but I have no regrets.

cloddopper · « **Reply #8 on:** June 06, 2015, 10:03:00 am »

You may find that after to or three seasons of growing in the internal bed that you have to completely renew the soil because you have got perennial diseases and pests in it .