What type of medium are these planted in? What, if any fertilizer has been used? How much? How often? Have the plants ever gone dry?

They are just in normal "general purpose" gardening compost.

No fertilizer has been used.

The plants have never been dry (or too wet).

Thanks

i hope small pots are not in sun ????

when working in pots.. a potting media really helps insure moisture thru all pots ... making it predictable ...

can we have a pic or two ...

i dont understand why they have to go in the house every night.. they are not babies .... which makes me wonder if you might not be applying too much love ...

its rather simple to fight slugs in a small area ...

ken

Do slugs ever eat healthy Hazelnut leaves? I've never seen it, and I live in the land of slugs, and native Hazelnuts are a weed.

Mike

Going by the language ('compost' for 'medium'.) and the fact the top pest s are gastropods I am guessing themadhedger is in the UK. If that is the case the seedlings should be outside all the time. There is no need to take them in at night. I highly doubt that slugs and snails will eat hazel. If these were mine I would plant them in the ground. Hazel is a robust native species and it's hard to kill it. If you have roe deer the seedlings do need protecting and grey squirrels will sometimes nip the tops out. But otherwise they are pretty much trouble free.

Thanks for the afvice.

Yes, I'm in the UK.

Okay, from now on I'll leave them out overnight.

They are in partial sun (afternoon only due to where I place them).

So should they be in the shade?

Should I just plant them in a suitable location (sun or shade)?

Or should I add something to the potting compost?

Best bet would be option #2-plant outside, in the ground, in suitable sunny to partially shaded area. Like as said by floral, not at all fussy plants.

Thanks, will do.

maybe bacterial blight?

http://www.omafra.gov.on.ca/english/crops/facts/12-009.htm

My young hazels will occasionally have dark leaf mottling.

Thankfully it doesn't look like that. :)

do you have pics?

Not yet, will try and take some.