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New Raised Bed

dsherwin1984dsherwin1984 Posts: 2
in Tools and techniques
Hi,

I'm a complete novice and new to gardening, so looking for advice on if my plans are right for a raised bed. I've just created a raised bed out of treated timber joists. It is 6 metres x 1 metre and 45cm high. I stretches across the top of the lawn, although there wasn't much grass and it was more weeds. I prepared the area by killing the weeds and then tilling the soil about 10cm deep. I then built the raised bed on top of this.


1. My plan is to line the sides of the bed with a damp proof membrane to preserve the timber. Is this correct?


2. Do I need to line the bottom with a permeable landscaping fabric?

3. Should I place a layer of horticultural grit / rocks / broken bricks in the bottom to ensure there is sufficient drainage? if so, should there be landscaping fabric below and above this to prevent the rocks mixing with the soil?

4. I was then going to buy new topsoil and compost and mix together to fill the bed. what are the ratios? Can I use any compost? I've seen things like spent mushroom compost and manure, are these suitable?

5. For water, because its a large bed. I was just going to by a soaker hose (one the seeps water along the entire hose) and lay this on the surface and then just connect to my hose and tap when I want to water. Is this acceptable?


I don't think I have a particular issue with clay soil (I have an image of clay in my head and my soil does not resemble that at all.

In terms of what I want to grow, I'm not to sure but given the size I was thinking maybe some ornamental plants but also some edible fruit and veg that the children can get involved in. Is it possible to grow the two in the same bed?

Thanks in advance

Posts

  • FairygirlFairygirl Posts: 55,117
    Hi @dsherwin1984. That's a sizeable bed you've made,and one thing I would suggest is to divide it into sections. That way, you can have different soil mediums, especially if you want a big variety of planting  :)
    I always line raised beds, so I think that would be a good idea. It also helps retain moisture a bit more, which is also good as raised beds tend to drain a bit more quickly.
    I don't put anything on the bottom. Mine are open to the ground below. If you want to add gravel/rocks etc in the base, then yes - a layer will prevent the soil you put in the bed from escaping.
    Watering system sounds fine. Many people do exactly that if they live in a drier area  :)
    As for the contents of the beds. It will take a huge amount of soil to fill something that big, so a bulk bag of topsoil would be beneficial. Probably two. You can then mix in manure and compost to get a good balance. I wouldn't worry too much about the exact amounts.
    Mushroom compost is good but slightly alkaline so bear that in mind if you want to plant anything that wouldn't like it. You're aiming for a good, friable mix, that runs through your hands nicely. You'll need to add over time, as the contents will tend to settle. 
    Hope that's of some help  :)
    It's a place where beautiful isn't enough of a word....



    I live in west central Scotland - not where that photo is...
  • JennyJJennyJ Posts: 10,576
    1. Yes, although thick plastic like old compost bags will do the job if you don't want to fork out for special membrane.

    2. No, it's better if your raised bed can drain freely to the soil underneath.  Any weed roots left behind that would grow up through the whole depth of the bed would make short work of a membrane.

    3. You can do, particularly if the soil underneath has rubbish drainage (ie if puddles form when it rains and take a long time to drain away)

    4. What @Fairygirl said!  No mushroom compost if you want to grow acid-lovers, and be sparing with manure if it's fresh.  Best left to rot down then used as a top-dressing next year.

    5. Sounds good, but remember to water in individual plants when you first put them in (a watering can with no rose is best for directing the water to the roots of each plant).

    And yes, you can grow ornamentals and veg together if you like.  Just remember that most veg like sun so they won't want to be shaded out.

    Doncaster, South Yorkshire. Soil type: sandy, well-drained
  • FairygirlFairygirl Posts: 55,117
    Yes - I forgot to say that @JennyJ. Definitely you can grow both ornamentals and edibles in the same space.
    Cottage gardens were always done this way in the past, and it helps with pollination and helps with attracting predators for any pests, like aphids etc,  too.  :)
    Some things, like lettuce for example, will be happier in shade, so do a bit of research before planting anything out etc.
    You're right about watering each plant in at the start too Jenny.  :)

    It's a place where beautiful isn't enough of a word....



    I live in west central Scotland - not where that photo is...
  • JennyJJennyJ Posts: 10,576
    I'm reminded of Geoff Hamilton's TV series "The Ornamental Kitchen Garden". 
    Doncaster, South Yorkshire. Soil type: sandy, well-drained
  • dsherwin1984dsherwin1984 Posts: 2
    Thank you for all the advice. I don’t think I have an issue with drainage so I might just mix some compost and grit with the existing soil to make sure then put the new soil/compost on top. I don’t want to prevent worms getting through. 
  • NollieNollie Posts: 7,529
    Sounds good, but I would probably mix it up a bit, rather than having two distinct layers, so once you have added grit to the existing soil, add half of the new material then mix that up a bit with the layer below, then top up. The worms will arrive and mix it all for you eventually, especially if you add fresh mulch annually.

    As fairygirl says, the contents will settle, so its a good idea to wait a month or so before planting up, ideally after some heavy rain. Then top up if necessary. You will need nearly 3 cubic metres of new material to fill a bed that size.

    Try and aim for a PH of around 6-7, which suits most garden plants and vegetables. Soft fruits like raspberries prefer a more acid soil, but probably not a good idea to include those anyway as they will take over! Lots of vegetables are ornamental, like crimson-flowered runner beans grown up a wigwam, rainbow chard, curly kale etc., and nasturtiums and marigolds are good vegetable companion plants and easy to grow. 

    If you are wanting to grow tree fruit, consider espaliers along the back if the bed is against a wall or fence. If you do include any fruit trees or shrubs remember that they will take up a fair amount of space and need more water than a soaker hose can provide, so be prepared to water those more deeply.

    Sounds a lovely project, do post some pics in due course!
    Mountainous Northern Catalunya, Spain. Hot summers, cold winters.
  • FairygirlFairygirl Posts: 55,117
    That's the reason I suggested dividing the length up into smaller sections @Nollie. You can then have appropriate conditions if you want plants that have differing requirements. I've done something similar here, as we have heavy soil and lots of rain, and it meant I could create a drier spot for those that like freer draining soil.  :)

    @dsherwin1984 - I think it's always best to mix the soil too, rather than have layers, as Nollie says. You can certainly have broken bits of rock etc in a little layer at the bottom, as the bed's quite deep, but the growing medium itself will always be better if it's all mixed together.  :)
    It's a place where beautiful isn't enough of a word....



    I live in west central Scotland - not where that photo is...
  • NollieNollie Posts: 7,529
    Yes of course, @Fairygirl, I guess the dividers would have to go right to the ground to contain each type of soil, tho? 
    Mountainous Northern Catalunya, Spain. Hot summers, cold winters.
  • FairygirlFairygirl Posts: 55,117
    edited September 2019
    Yes - that's what I did @Nollie . Most of my raised beds are completely separate as they're on an awkwardly angled fence, and they're different heights and widths too, but I have another bed which is divided into three main sections  :)
    It's a place where beautiful isn't enough of a word....



    I live in west central Scotland - not where that photo is...
  • purplerallimpurplerallim Posts: 5,287
    edited September 2019
    Also it depends on what fruit/veg you decide to do as to whether you add manure or not. Potatoes would like it, but carrots like the soil less rich. So maybe leave out manure until you are sure what you are planting where, it can always be added later @dsherwin1984 .😁
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