[AlaninCarlisle]

Just noticed that an unused part of my garden that I was about to dig over has sprouted some huge mushroom-type things, about a foot in diameter plus some large puffballs. I'm just going to dig these in but wonder if it might affect next season's crops? Obviously I wont risk onions, leeks etc there but what about other crops?

[Pescador]

Photos would help to identify. Off the top of my head I can't think of any pathogenic fungi that produce large fruiting bodies, so they may not be harmful at all.

[AlaninCarlisle]

Yes, I should have photographed them before digging them in. They are in an area close to a large apple tree that I''ve heavily mulched with horse-muck over the past few years so that may explain their presence

[sunshineband]

You might have found these were Giant Puffballs, which are delicious to eat. If any form next year, perhaps photograph them to check their ID and you may find you have your own delicacy growing at the end of the garden!

[Kleftiwallah]

When the memsahib and me used to take canal boat holidays (faaar too expensive nowadays) the normal  position was standing on the 'deckhouse' roof looking into the canal side fields looking for puffballs and mushrooms.

Cheers,  Tony.

[Deborah1]

Yes, I agree with previous replies. They sound like Giant Puffballs. And they like nutrient rich ground, so your heavy application of muck would have pleased them! 
By digging over the patch there is a chance that you have damaged the mycelium, so they may not necessarily reappear next year if you were hoping for a repeat crop!

[AlaninCarlisle]

Not worried about harvesting the mushrooms. We have a field of pasture that contains more than we can use. I was concerned that the mycelium may affect any future vegetable crops

[snowdrops]

Not worried about harvesting the mushrooms. We have a field of pasture that contains more than we can use. I was concerned that the mycelium may affect any future vegetable crops

Yes but only to the good, that’s what no diggers promote 😊