[Goosegirl]

I know rasps prefer a slightly acidic soil but need a good mulch in spring to conserve water. I have plenty of mushroom compost and would like to use it on my rasp beds. If I do, would it cause any problems as it tends to be more alkaline. Would a dose of sequestrine help?

[moose]

I'm not sure how much difference it would make. I have heavy clay on top of chalk and I gave up doing soil tests years ago. When I had them done I got results showing Ph of 7.2-7.5. I have never done anything to alter that and my raspberries have been growing happily and producing loads of fruit for 15 years. I do grow blueberries in pots of ericaceous compost but everything else is sown or planted in the soil and I'm happy with the product. I'm not aware of anything that would grow any better if I set about altering the Ph value which is not a simple job(IMO).

[Kristen]

My soil is alkaline and I've never worried about a one-time generous application of Mushroom compost - benefit outweighs slight alkalinity increase.  Year-after-year might be a different story.

Wood ash is often recommended for Raspberries, and that is alkaline too.

[Goosegirl]

That's good news. While clay soils can be slightly acidic, mine is alluvial silt and, as far as I know, is about neutral pH. I will put on a goodly amount then wath the leaves to see if they show signs of chlorosis. If they do, I will water some Sequestrine in.

[Kristen]

Could chuck some Sulphur chips down anyway, if you are concerned? They are a slow acting solution, so by the time the plant might otherwise be stressed they would, hopefully??!!, be having an effect.