[Goosegirl]

I have 3 unopened large bags of been and queued compost. Will they be ok to use for seeds, potting-on etc? I can always add nutrients as needed, but will seedlings do ok in it as they don't need much nutrient?

[mumofstig]

I'd still put just a little feed in even for seed sowing, just in case they don't get pricked straight out.

[Yorkie]

Don't often disagree with mum, but I wouldn't bother putting any extra feed in at the start.  If it's too rich it can be detrimental to the seeds.

[JayG]

Unless the bags have been stored somewhere very wet, the only nutrient which may have been lost is nitrogen, which isn't that important for seed sowing, although it's possible it may not be as sterile as it was when fresh.
(I'd use it anyway, but then again I am a cheapskate!  )

As for using it for potting on or growing, I remain dubious about how much nutrient content there is in MP composts these days, so I add some general purpose fertiliser to be on the safe side.

[Growster...]

The trouble with old bags (?), is that they settle into a gluey lump, and are full of condensation.

If you can open them and spread them around a bit, you may be able to achieve some sort of lighter compost, but after this time, they have decomposed even more, so don't expect miracles!

I think I'd use them half-and-half with garden soil in big pots for tomatoes in the green house if that's any help!

[Goosegirl]

When I open one of these big bags, I take some out to put into a big plastic waste bin under the staging in the greenhouse and is handy to sow and pot on. The rest of the bag is then light enough to be moved into the GH as well. I usually leave the bag open so air can get to it. I will give it a go anyway, but add BFB when potting on. I agree too that seeds need very little nutrients to get going.