Is their such a thing as too much compost?

[Schroeder]

I purchased compost from a landscaping company. They say it is mostly yard waste with some horse manure. It is beautiful, black, fluffy stuff. If money were not an issue, would there be drawbacks to filling a raised bed (for vegetables) solely with compost?

 

[boggybranch]

I would not hesitate to fill beds with compost that I, personally, made (of course, incorporating it with the garden soil).......but, I wouldn't do it, otherwise.

My dad got a trailer full of what you are describing and we built and filled a raised flower bed with it, last year. It turned out to be a total disaster and we had to redo the bed just 3 or 4 weeks ago.

 

[digitS']

I agree with Boggy. Compost quality is variable.

Also, incorporate it with soil in your garden beds (see above). It will continue to decompose and within a year or 2, maybe less in warm climates, the compost will have disappeared almost completely. A raised bed will be an empty bed.

Unless you really have nothing but rock, your native soil is probably worth enriching and using.

You can plan on continuing to add compost regularly, whatever the case.

Steve

 

[Greenthumb18]

I agree the more compost you add to your garden soil the better the plants will be when you'll plant them. You'll have a more enriched soil with all of the beneficial microorganisms.

 

[patandchickens]

There are two ways in which you can indeed have "too much compost"

One is, as mentioned, that the compost is unlikely to be "nutritionally balanced" for the plants, and single-source composts are especially prone to this. If you mix a bunch of different kinds of compost, not as likely of a problem but still not a bad idea to get a soil test done on it.

The second is that compost is very water-retentive, especially "professional" compost as opposed to what comes out of your own pile. If you have too high a %ge of compost in your soil or try planting into pure compost, it can get awfully difficult to avoid waterlogging and rotting your plants.

Honestly I do not think any real purpose is served in trying to grow plants in just compost. Your soil, even if you feel it is not good soil, is still SOIL (well unless you live on bedrock <g>). It has mineral nutrients; it has mineral particles that help provide structure; it has microorganisms (yeah, even if it is just clay, it still DOES), etc etc. Mix soil and compost together to get a better growing medium; or at least fracture the soil up severely before you dump compost atop it, so that it will begin to mix naturally together and will be easier for plants to root down into the underlying soil.

Finally, municipal compost not-infrequently has stuff you really don't want too much of in your garden, e.g. heavy metals or pesticide residues or nasty weed seeds, so I would be *real* leery of using it as the dominant component of a new bed unless there was *literally* no other doable alternative.

JMHO, good luck, have fun,

Pat