Help - Raised Garden Bed

[CrackX]

I am new to gardening. I want to build a 20" high raised garden bed against a brick wall. What I plan to grow in it are butternut squash and courgette/zucchini. Do you think the brick wall will have any affect on the growth of these plants? Is 20" good enough?

I will add a layer of membrane to prevent weed growth. I am afraid the bed might lack decent drainage so I will add an inch layer of horticultural grit right at the bottom. I will be using loamy topsoil to fill the bed and a layer of compost at the surface. Will adding the horticultural grit do any harm?

[Bill HH]

Welcome to the vine, I will tell you how I would do it, right or wrong, On the bottom I would put a layer of thick cardboard, the brown corrugated stuff, then 3inches of newspapers crumpled up, this will all retain moisture and encourage worms and supress weeds, next loads of home made compost grass cuttings etc and or manure, maybe 6 inches. Then soil and Multipurpose compost mixed according to how much MPC you can afford. As it is a raised bed it should drain without the gravel, gravel is a pain it will work its way up. In with your soil/MPC I would add chicken manure pellets or other manure and some Blood fish and bone. Make sure you have contracts to supply Sainsburys with the bountiful harvest. The weed barrier is in my opinion not needed, in that light mixture any weeds that do make it are easy to pull out. If the wall faces south there will be no problem, if it is shading the bed you may struggle. You could erect a trellis and grow stuff up that at the same time. The soil will sink over the year and need topping up.

(added) 20 inches is relatively deep and more than adequate, the wall will be beneficial if its facing south, it will help retain warmth and aid you plants. make sure the bed is not so wide that you cant reach right across, you need never dig this bed if you don't walk on it.

[KevinM67]

For me BillHH has nailed it.

I wouldn't waste my money on grit because as the soil settles over time, the grit will make its way up.

Building layers as BillHH suggested using relatively cheap/free things like paper, cardboard, grass cuttings, will produce good soil structure, suppress weeds and provide adequate drainage.

And anyway, things like squashes quite like soggy conditions.

[Bigmallly]

Welcome to the vine Crack. I can't add to what Bill has already said.

Sorry, yes I can..........................make it 10" deep & save some cash..........

[Bill HH]

Yes 10 inches would e fine, I had assumed crackx had chosen 20 inches to save bending. Besides if next year it is required for roots like carrots 20 inches would be superb.

[CrackX]

Welcome to the vine, I will tell you how I would do it, right or wrong, On the bottom I would put a layer of thick cardboard, the brown corrugated stuff, then 3inches of newspapers crumpled up, this will all retain moisture and encourage worms and supress weeds, next loads of home made compost grass cuttings etc and or manure, maybe 6 inches. Then soil and Multipurpose compost mixed according to how much MPC you can afford. As it is a raised bed it should drain without the gravel, gravel is a pain it will work its way up. In with your soil/MPC I would add chicken manure pellets or other manure and some Blood fish and bone. Make sure you have contracts to supply Sainsburys with the bountiful harvest. The weed barrier is in my opinion not needed, in that light mixture any weeds that do make it are easy to pull out. If the wall faces south there will be no problem, if it is shading the bed you may struggle. You could erect a trellis and grow stuff up that at the same time. The soil will sink over the year and need topping up.

(added) 20 inches is relatively deep and more than adequate, the wall will be beneficial if its facing south, it will help retain warmth and aid you plants. make sure the bed is not so wide that you cant reach right across, you need never dig this bed if you don't walk on it.

Thanks Bill HH, your detailed advice will really help me out in this, looked all over the internet for a detailed advice such as yours.

[CrackX]

In a year or two, I plan to switch over to tomatoes and spinach's. Is there any harm in keeping it 20"?

[snakeshack]

I suggest you put a polythene membrane between the soil and the brickwork, this will stop water moving into the bricks which would result in increased water requirements and also possible frost damage to the bricks over winter


Sent from my iPhone using Grow Your Own Forum

[Bill HH]

I suggest you put a polythene membrane between the soil and the brickwork, this will stop water moving into the bricks which would result in increased water requirements and also possible frost damage to the bricks over winter


Sent from my iPhone using Grow Your Own Forum

Good point, I assume the bed will have a back to it so maybe a 2 inch gap between it and the wall would suffice.

[veggiechicken]

Hello CrackX and welcome.
A couple of questions if I may!! Will the raised bed get lots of sunshine or will the wall shade it? Courgettes like sun
Make sure that you can reach across the bed (about 2'-3' max)as the wall will stop you accessing the back.
You will need to keep an eye on the watering as the bed may be in the rain shadow of the wall.
Finally, where do you live? - if you could add your location to your profile it would help us with advice as the weather varies so much in the UK.

[CrackX]

Hello CrackX and welcome.
A couple of questions if I may!! Will the raised bed get lots of sunshine or will the wall shade it? Courgettes like sun
Make sure that you can reach across the bed (about 2'-3' max)as the wall will stop you accessing the back.
You will need to keep an eye on the watering as the bed may be in the rain shadow of the wall.
Finally, where do you live? - if you could add your location to your profile it would help us with advice as the weather varies so much in the UK.

The raised bed will get a fair amount of sunshine. Now with the summer weather, atleast 6 hours per day I guess. I live in Edinburgh, Scotland where the weather gets quite depressing at times, but looking at the summer forecast, we will get an average of 16-18°C (60-65°F) so is the temperature sufficient or will I have to take extra measures?

By the way, do I omit the layer of membrane?

[CrackX]

Thanks for the advice. I will add the following in order:
Cardboard
Newspaper
Farmyard manure - at this point can I add earthworms?
Loamy topsoil
Multipurpose compost

[Bill HH]

Have you heard the phrase "Build it and they will come" Well that applies to worms as well. That's if you have worms of course, If your up North I hear the Newzealand flat worms have killed em all.

[CrackX]

Have you heard the phrase "Build it and they will come" Well that applies to worms as well. That's if you have worms of course, If your up North I hear the Newzealand flat worms have killed em all.

My garden is undergoing a process of complete refurbishment where soils will be getting lifted and monoblock paving will be done. After that, I don't think many will remain, can I not buy some? If so, how do I release worms? Also, I don't think I've noticed any worms before in my garden.

[gardening_gal]

I found NZ flatworms here last year for the first time, they were a nightmare. Tiny black eggs everywhere too. I picked up as many worms and eggs as I could find but I'm sure there were many more just lurking.

I've yet to see an ordinary worm here. They must be dwindling in numbers.

I've recently read an article that reckoned they don't actually do the harm to worm numbers that was originally thought, but I'm not convinced.