How much compost should be in topsoil?

Eyeore

Hi, we are buying in some ton bags of screened topsoil and I have gotten two competitive prices that I am considering. My question is regarding the content of peat free compost that is added in, one supplier has 25% compost and the other has 40%. The prices vary a little but not much. I'm unsure if there is much difference and what are the benefits of having more compost? It will be used mainly in the polytunnel and some outdoor beds for growing veg etc. Any information would be greatly appreciated.

Sonnenblumen

Eyeore wrote: »

Hi, we are buying in some ton bags of screened topsoil and I have gotten two competitive prices that I am considering. My question is regarding the content of peat free compost that is added in, one supplier has 25% compost and the other has 40%. The prices vary a little but not much. I'm unsure if there is much difference and what are the benefits of having more compost? It will be used mainly in the polytunnel and some outdoor beds for growing veg etc. Any information would be greatly appreciated.

I'm glad to see vendors offering peat-free compost, but as a growing medium good soil is much better than compost. The latter is principally a soil conditioner albeit with some (depending on quality) nutritional value. Soil also retains moisture better than compost and is less likely to dehydrate, an important consideration when growing plants and/or vegetables etc.

All things being equal I would opt for a higher soil content.

Beware sometimes recycled compost can be used to mask poor soil.

Eyeore

Sonnenblumen thanks for that reply. I guess the 25% one would be the better option so and seeing as it will be mainly used in the polytunnel I will need the water retention qualities to be as good as possible.