Raised beds

Personally I don’t grow in raised beds. However a couple of my friends do. The beds were filled with bought compost from the garden center. The first year all went well but the following year things didn’t grow well. I think that the compost lacks enough nutrients for healthy plants.  What is the best way to rectify this ? The work would be done over winter.

Thanks, look forward to suggestions.

What's the difference in growing in a raised bed and growing in the ground? A no-dig person would add a couple of inches of compost to the surface - could they do that?
Or add whatever fertilisers were appropriate for whatever they were going to grow in the bed as you would in a normal bed.

Are you sure the problem is the compost? I don't add manure in the winter etc. I use compost from my bins as a mulch, BFB and that's about it.
Are they looking after them as well this year round? Are they feeding now?

What is the raised bed made of? What's under it all? Any liners etc?

Lots of good questions already asked. My raised beds are just soil/compost resting straight on the existing soil and I add a layer of compost over the top each autumn/winter but even without that everything would still grow ok. Maybe their raised beds are actually containers in which case they will need to either refresh with new compost or rejuvenate with fertiliser and minerals.

I always add manure to raised beds in winter. Add combinations of BFB, chicken manure pellets or lime when planting. I’m not very good at mulching. But it’s something I want to improve on.

I think we need to differentiate between raised and edged beds, some raised beds can be quite deep and I have found that they lack moisture if predominately shop bought compost and are very poor at retaining nutrients after year one.

All my beds are edged to a maximum of 200mm (8") but mostly 150mm (6"), I feed the beds regularly with BFB throughout the year and those that will hold brassicas next season will get a good feed with manure. The beds that grow squashes are fed with manure at point of planting. I also have the luxury of space and some beds are left empty each year but covered with weed membrane on top of a layer of compost.

About six beds have been dug to a depth of 600mm (2') and sifted for growing carrots and parsnips with two being left empty each year. My bean frames are permanent and I just dig trenches and replace with compost from my bins, The excavated soil is mixed in with the compost remaining in the bins.

I grow a lot of brassicas and find that compost is too loose as a growing medium and poor at supporting the plants.

Thanks for all the replies folks. I will investigate further and pass on your advice. One of the growers is in Holland and under that bed is sand but quite how the other is constructed I am not quite sure, both the beds are quite deep, I will investigate!

Depends what was in the garden centre compost. Bagged compost usually only has enough nutrients for a limited growing time. Pure (i.e. green waste or home made) compost has more nutrients but isn't a good growing medium for an extended period of time since it's always breaking down. Peat is low in nutrients but is naturally more resistant to degradation. The compost has likely lost most of its nutrients and compaction may have reduced its water and air holding capacity.

Soils typically only contain 5-10% organic matter, so for filling raised beds a loamy topsoil mixed with some compost is better. If the garden centre compost was mostly peat I would dig in lots of topsoil and some real compost.

Would moss raked out of the lawn added to homemade compost increase its waterholding ability without causing 'mossy problems?