What to fill a raised bed with?

suyinkan

I’m sure this is a commonly asked question so apologies.
I’m new to vegetable growing...can I fill a raised bed with multipurpose compost? 
Also should I remove the turf or just put cardboard down? 

Obelixx

Have you simply made a raised bed on top of grass?   How deep and what size?

I think a mix of John Innes no 3 loam based compost with some multi purpose compost would be better than just MPC which, in my experience, is low in nutrients and inclined to get claggy when wet or shrink when dry.

Then what you grow will depend on where you are and what you like to eat.  I tend to grow crops which are expensive to buy or hard to find but I also have loads of space so can pretty well plant anything I like.  In more limited space you need to concentrate on stuff which tastes better freshly picked and/or is hard to find or costs a fortune or doesn't store well.

suyinkan

Thanks for the reply!
I have plastic link-a-bord raised beds... 1.4m square, one is 15cm high and the other is 30cm. and yes they’re just placed on top of the grass at the moment. 
l’ll be growing courgettes, kale and peas to start off with. 

Obelixx

Others may disagree but that's quite a large quantity of compost to buy so you may want to see if you can get some topsoil delivered from a good source.   If not, a mix of John Innes loam based soil and up to 20% MPC for water retention.  If you have cardboard to cover the grass then lay it but otherwise it should be fine just covered in soil of compost.

Kale is a brassica and will appreciate some lime added to the row to help combat club root.   Courgettes like to be warm, well fed and not get thirsty.   peas also like to be well fed and watered but are good in cooler conditions.  Bit late to be sowing any this year so you need to get a move on or else sow some in root runners to get them started ready for planting out later when you have your beds filled.

You need to take crop rotation into account to get the best of your soil.  Have a look here for starters - https://www.rhs.org.uk/advice/profile?pid=124 and then here - https://www.rhs.org.uk/advice/grow-your-own/allotments/making-the-most-of-your-plot which covers bigger plots but has useful tips.

suyinkan

Thanks for the advice! 
I’ve got all these started from seed last month so I’m now wanting to plant them out, hence trying to get the raised beds sorted. 

Zoomer44

Is there a reason for only grow courgettes, pea's and kale were they free seeds with a magazine?

The bed 15cm high, if you remove the turf, there will then be no need to add top soil or cardboard.

The bed 30cm bed, again removing the turf will reduce the cost of buying top soil and compost. 

suyinkan

They were jut what I fancied trying out. I’m new to vegetable growing so I wanted to start with just a few different kinds. 

Im not sure I understand what you mean by not needing to add topsoil in the 15cm bed. Even if I remove the turf I would still need to fill the raised bed wouldn’t I? 

Dovefromabove

When I had raised beds for vegetables I filled them with a mix of topsoil and well rotted farmyard manure in a ratio of approximately 3:1

Iamweedy

Unfortunately soil settles down over time and you will need more. As I have found. Do not despair. 

Nollie

Hello Suyinkan,
I would recommend you do remove the turf, dig over the soil underneath, remove all weeds, especially perennial weeds with deep tap roots and then incorporate your compost into this soil so it is mixed up. Otherwise you will have just a layer of compost sitting on top, drying out more quickly. Then you already have the essential soil element, with the nutrients, minerals and soil microorganisms that your plants will need to grow well. Providing you have good soil and not a load of rubble underneath the turf, you may not have to buy any additional topsoil, just compost to mix in. 

I would put the peas in your 15cm high bed in a mix of soil and compost, and 2-3 courgette plants, which are bigger and hungrier, in the deeper bed, additionally mixing in a bag or two of composted manure in that bed. The peas will need something to climb up.

Its a bit early to be planting out your young kale plants, usually you harvest the peas (legume family), enrich the soil a bit plus add a little lime if your soil is on the acidic side, then plant out the kale (brassica family) in same bed around June/July or whenever your peas are finished. Kale is really a winter crop, but if you want to grow it earlier, you could put a row in with your peas, don’t let the plants get too big and harvest the young leaves. 

saiwha

Buying in can be somewhat expensive but if you're not worried about cost then that will be the easiest option. Like others have said a mix of top soil, compost and John Innes will be fine.

If you want to do it on the cheap, which is what i did, take the top soil from the area that you want to place your beds i.e lower the ground around the beds and use that top soil mixed with MPC add some blood fish and bone whilst your at it for good measure. Then find a local arborist that will give you wood chips for free to fill in the area that you have dug around your beds, provides a great weed barrier and looks pretty good as well.