Mushroom Compost for Fruit Trees

HappyEarth starts with ...
Hey guys, was wondering what peoples experience has been with using mushroom compost on fruit trees?

Ive got a few bags of the stuff at the moment, but a little hesitant to use it on the fruit trees as Ive heard it has a pretty high pH. Anyone had any postive/negative experiences with mushie compost?

Rich
www.happyearth.com.au

amanda says...
Hi Happy Earth - Mushie compost can/may contain a lot of salt. I am pretty sure it was in Kevin Handreck's "Gardening Down Under" (CSIRO) that I read this. With my salinity issues - it stuck in my head as something to avoid so I don't use it - probably not an issue for u tho'.

U could always put it in your worm farm or compost bin if u are not sure...? That would sort it out...

Brendan says...
Hi HappyEarth,
Apply the mushroom compost as you would fertilizer, a handfull to the sq metre under the canopy of the trees. Sprinkle it with a small amount of powered sulphur and water in.
Works for me :-)

speedy says...
Mushroom compost (Agaricus spp.) is usually formulated from straw and animal manure
which are partially composted together with lime and gypsum , then the process is stopped and it's steam pasteurised before spawnning.

I have soil that's naturally above pH 7 but I still use mushroom compost.
I don't feel the need to add sulphur ( there's sulphur in the gypsum)

I find that the Calcium in it helps to loosen the clay in the soil and make it more friable.

It's also very effective at wetting hydrophobic soils (non-wetting sands).
I prefer to use mushroom compost than soil wetter from a bottle.

I use it whenever i can get it, it's a great soil additive.

Chris says...
ph of mushroom compost varies quite wildly depending on the source. It tends to be quite alkaline (well above 7) most of the time.
I'd view it as a soil conditioner rather than a fertiliser. It is spent mushroom compost after all.

Rev says...
I havent seen the inner workings of the Aussie mushroom trade - recently

might be better now theyve withdrawn benlate from the market.
benlate is a fungicides that is also and endocrine disruptor. it WAS used to inhibit competitor moulds

now i think they use its metablite Carbendazim. It also has issues.

Also in some mushroom industries they use a lot of salt. salt boost production somehow and also can be used to salt out bad (contaminated) spots on the casing

personally i wouldnt put the stuff anywhere near my veggie gardens.
maybe on my fruit trees
but really its just too expensive - especially considering its a disposal problem for the farm. I think they saw us coming!
The only real reason id buy is to use the still living mycelium as spawn for a mulched garden

im sure itd be cheaper to make your own compost, and safer

chook manure, straw, lawn clippings gypsum
throw in some dolomite for the plants
beef it up with a little Kelp and some trace elements...

yum yum

kert says...
There's still the issue of high salinity in mushroom compost.

kert says...
Hmmm, gypsum is useful as clay breaker not sure if it offers much in combating salinity. Mushroom compost typically has a lot of calcium chloride in it already . Adding gypsum would increase salinity as measured by its osmotic pressure.

kert says...
I read the references and it appears as if gypsum increases the salinity as measured by osmotic pressure but decreases sodicity which is the sodium locked in the soil mainly as a clay constituent. Thus gypsum is helpful but not because it decreases salinity.

Rev says...
calcium sulphate - low solubility
calcium displaces sodium ion
sodium ion pairs sulphate to make soluble sodium sulphate - and leaches away

kert says...
As far as i know mushroom compost contains no clay;so all the theory of displacing sodium from clay particles and then washing it away does not hold. Mushroom compost already has a large amount of calcium chloride which would do the cation exchange, anyway. I'm afraid when the term salinity is used with mushroom compost it is meant as total solutes not just NaCl. Anyway what would sodium chloride be doing in mushroom compost? It would not be deliberately placed there.

Mari says...
Hey what a good site! I stumbled on it looking for answer to whether I could safely put the Calcium chloride into my composting toilet (they say it's septic safe)or compost. I've got lots of it at the moment trying to stop mould in the cupboards. BTW mushroom compost is really cheap around our way. If you go and get it by the trailer load straight from the farm it's about 50c for a bag that you see on side of the road for about $3 in the suburbs of Brisbane.

Can anyone help with the CaCl2 in compost?

Pictures - Click to enlarge
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ringelstrumpf says...
I love mushroom compost and I once bought 5 m³ for our not so big Brisbane garden. I used it on the veggies.
Maybe I shouldn't have because of the Chemicals they use. I think the main advantage is that mushrooms are somehow good for the soil (Stammets, Mycelium running).
Recently, I read something about gypsum, that from most sources (Bunnings etc) the gypsum contains lots of nasties (was it Arsenic??).

amanda says...
I always thought Speedy's advice (way back when..) was great in these instances - in that he suggested to simply compost anything you are concerned about first.

You can even add some "inorganic" fert's this way...such as manganese, etc (for your particular soil deficiency) and the (hot-aerobic) composting process will turn it into something more available and natural for your plants.

If u concerned about salts etc in mushroom compost - then compost it - the process will sort things out for you.

Of course - Speedy explains it so much better than I can...

Fert's intended for food crops must state the heavy metal concentrations - if not - don't use it. Mined gypsum is so cheap anyway.


(ps Speedy - I hope I have got that sort of right?... I know u can't just compost any old thing...eg: treated pine, toxic sludge etc...

Brendan says...
Yeah kert, I remember my mushroom compost tested 8 to 8½ pH some time back, the powered sulphur helped to bring it back to 6½ - 7 pH.
I was taught to apply m. compost @ one handful/sq m. around fruit trees? (like fertilizer).

Now I think the rain has washed it all away anyway :-(