mulching

I have planted some cuttings of currants and gooseberries in a nursery bed until they grow enough roots to move on to their final positions. What is best to use to keep down the weeds? I am worried about using manure because of the risk it will rot the cuttings or burn them. The wood chippings i have access to have a high content of pine needles which i have been told to use only for paths by older plot holders. I think this has something to do with raising the acidity of the soil, and i have benefited from this elsewhere, by using it in planting my blueberries and cranberries. Also many of my cuttings are very short so i don't want to completely loose them in the mulch does anyone have experience of doing something similar? advise please, thank you. 

If you want to keep down the weeds could you not just pull them out?

Possibly not very helpful at this stage to suggest that a nursery bed should be weed-free to start off with to avoid competition with young plants or cuttings, but in any case I would have thought that unless you've gone into this on an industrial scale an occasional bit of careful hoeing or hand-weeding would be sufficient.

I wouldn't mulch with anything that might change the chemistry of the soil, nor cold-composted compost which is likely to contain weed seeds - have you any weed-free used compost you could use as a mulch?