Rotten swede

I think what you have is called Brown heart which is a deficiency of Boron, really spoils a nice looking Swede.

I believe seaweed meal will replace missing vital minerals in the soil. I use Maxicrop products plus a local forage on the shore to top up my compost heap though I got permission first.

If it is soft and stinks it is soft rot. This is caused by bacteria invading the roots, usually through a wound or via the crown.

I does look like boron defficiency. It is more likely on very light soils in dry periods such as the south and east experienced this August -October.

It does not mean that your soil is necessarily short of boron. Boron is easily locked up if the soil is made too alkaline. Did you by any chance apply a dusting of lime to the seedbed to stave off clubroot?

These things are not always clear cut. Sometimes it starts with cracks in the crown due to boron defficiency which are invaded by soft rot bacteria which makes them rot.

Greenhead, I also have clubroot on my plot. My way round it is to grow the swede on in 5" pots before planting out. They get a better root system before being subjected to club root.

I know many sources say swede won't transplant but it does.