Soil / Compost mix for raised bed (flowers / shurbs)

[AlmostCutMyHairToday]

I'm a gardening newbie and have a raised bed in which I'd like to plant some more shrubs and flowers that according to RHS prefer well drained soil (list below). The bed already has soil and some shrubs, but the soil is a bit sunken so I need to top it up.

Should I top up the bed with 100% compost, or do I need to mix the compost with some topsoil?

I've heard Melcourt SylvaGrow Multipurpose is a good compost, but I'm a bit confused whether I have to mix it with something else, and if so exactly what? I see Melcourt does two types of topsoil - Blended Loam or Extra Fine.

Any advice much appreciated :)

Armeria Dreameria Vivid Dream
Armeria Dreameria Dream Clouds
Erysimum Bowles Mauve
Erysimum Wallflower Taffetta Gold
Limonium Dazzle Rocks
The ‘Starlight Tulbaghia Collection’
Coreopsis grandilfora 'Solar Moon'
Erigeron
Foeniculum vulgare var. dulce
Anemone × hybrida 'Honorine Jobert'

Multipurpose compost is for pots and seedlings, just top it up with topsoil or any contents of a compost bin, or leaves, or even small sticks. Try whatever you have to hand first before buying anything. We just rake any garden debris onto beds and let it rot down in its own good time.

Our local recycling does 'soil enhancer' - lovely compost made from collecting the green waste bins. Three bags per visit, free. As well as making your own compost, maybe check to see if your recycling centr does the same.

I'd probably do mainly topsoil and then top dress with compost. Looking at your plant list I wanted to ask how much sun your raised bed gets? Just because most of the plants you've listed will be happiest in the sun but the anemone tends to prefer shade in my experience.

If you have an existing raised bed and are just topping up then I would just use compost. Melcourt is quite expensive and I would use it for containers, but would recommend something cheaper for topping up.

I have used a top soil/compost mix for setting up a new raised bed but found that it was much too heavy.

Thanks all! Sounds like it's fine to just top it up with compost then.

@SpecduckularlyQuackers - that's interesting re the anemone. It's a south facing, very narrow & sheltered garden with the raised beds against the fences so one side gets a bit more sun in the morning, the other more in the afternoon.

Another vote for recycled garden waste from the local council. I mix it with Melcourt & topsoil in large raised beds and with a handful of grit here and there in pots, and this works brilliantly. It helps to make the expensive compost stretch further. I can also use the ericaceous melcourt where I have acers and heathers.

I'm in the process of filling some raised beds. I've been shoving in all sorts of stuff 😁 Mostly compost when I've refilled pots that I've previously grown (or tried to) flowers and veg. in. The latest one we put down a thick layer of fallen leaves, then cardboard, then the raised bed, then twigs/thin branches and more fallen leaves. We're going to order a rubble bag of top soil, then top dress with fresh homemade compost (supplimented with bought if necessary) possibly mix in some rotted manure. Bake at 180°fan.