Soil for a new raised bed

[Pnwgardens]

I'm building a raised bed on top of what used to be a lawn. I'm thinking of using a 50/50 topsoil/compost mix.

Is this a good mix? Should I add anything else? Thanks.

 

[Chuck]

If you use topsoil you will be bringing in all kinds of weeds. Use a sterile garden soil and compost.

 

[Daren]

It all Depends on what you are growing in it Pnwgardens. But as a General rule of thumb Your 50/50 Sounds fine. But make sure you are only Adding Compost with good water retention as Razed beds have a tendency to dry fast. & as Chuck says if it is not Sterile expect to be weeding a lot!

 

[TomatoTango]

I reccomend a little bit of a lightening agent with water retention; something like vermiculite, perlite, or rice hulls. Manure, particularly aged stuff, is a really good amendment to add too, even if it does come with weeds.

 

[Pnwgardens]

I reccomend a little bit of a lightening agent with water retention; something like vermiculite, perlite, or rice hulls. Manure, particularly aged stuff, is a really good amendment to add too, even if it does come with weeds.

If I add that kind if stuff will I have to replace it after it decomposes?

 

[alp]

Don't think perlite will decomposes. Add horse manure as it could be obtained free. Line the whole bed with well rotted manure and some bark mulch of the smallest size. You could advertise in freecycle to see if anyone could give you some free. Make sure you have screen top soil or you might be in all sorts of trouble. You can add horticultural grit which is far cheaper than perlite.

 

[TomatoTango]

If I add that kind if stuff will I have to replace it after it decomposes?

Yeah. Horse manure and other organic materials like compost breakdown continuously and need replacing. I add aged horse manure to my raised beds every year, usually two or three times. Worms usually move in and eat up all the poop, turning it into nutrient rich castings. This can be sped up by covering beds when not in use with cardboard or shadecloth. A layer of leaves is always good too.

Perlite and vermiculite last for years. Ditto with other additives like rice hulls or zeolite. The rice hulls would breakdown fastest. Rock powders can also take years to fully breakdown and be absorbed.

 

[alp]

Yeah. Horse manure and other organic materials like compost breakdown continuously and need replacing. I add aged horse manure to my raised beds every year, usually two or three times. Worms usually move in and eat up all the poop, turning it into nutrient rich castings. This can be sped up by covering beds when not in use with cardboard or shadecloth. A layer of leaves is always good too.

Perlite and vermiculite last for years. Ditto with other additives like rice hulls or zeolite. The rice hulls would breakdown fastest. Rock powders can also take years to fully breakdown and be absorbed.