How do you stop worms getting into the heart of your cabbages. I recently took on an allotment that had been neglected, but am having this problem. Worms are quite long and thin and reddish.

yup... they do prefer the most tender leaves...

for me?
I try to pick them off before there's very many.
Once there is too many to hand pick, I either pull affected plants, or turn under and try another winter crop... like kale or radish / beets / chard / carrot.
Plenty of winter munchies besides cabbage...

Thanks for your reply, but you can't detect them until the head is split open. Hoped there was someway of dettering them.

Hi, can you post a picture?
Are they earthworms? I'm surprised at 'long thin red' because all I know are green or brownish.

Here in Seattle, red worms (as well as slugs, earwigs, and more) will be found in the protected parts of many different plants, brassicas, lettuces, leeks, etc. The only way to keep them out is to grow in worm-free soil, i.e. pots or beds with artificial soil well isolated from natural soil dweller populations. Worms will travel large distances over bare concrete to enter pots through unscreened drainage holes. That is all quite a bother, so perhaps it would be better just to resign oneself to always disassemble and examine garden produce before use.

Interesting problem. Worms. Years ago I had an onslaught of worms killing some of my tomato plants. Everybody thought I was crazy, had lost my mind. Which had me a little bit worried until I found one person online that had the same problem, then I found another. I was so relieved!

I'm told there were no worms in North America until the settlers brought them over from Europe. Interesting if true. Not native here.

Anyway, you didn't say if you were organic or not. I had an awful problem with pill bugs (wood lice) for years. The only organic thing that I found that would 'kill' them was pyrethrins. Other products like Spinosad just repelled them for a few days. Apparently pyrethrins will kill a great many bugs, both good ones and bad so you have to use it carefully around bees and beneficials. Anyway, they are super expensive and I couldn't afford to keep using them so I bought the synthetic permethrins. It says it kills around 100 different kinds of bugs and creatures. I can believe that. I don't have to spray it on the plants at all. I just spray it very lightly on the soil around the stem of the plants. It kills the pill bugs immediately and continues to work for about a month. This is the product I buy at my local hardware store.
https://bonide.com/product/eig...
You could try it. It might work well in your situation. Lots of luck and happy gardening.

Thanks for all your replies.
Sallyg : will take pic when next at the allotment. Very wet here in the UK this year. Maybe that's part of the problem.
Sedona Debbie: Thanks will look into this, not sure if it will be on sale over here. Did think the soil was good if there are plenty of worms.😕

I've had success using BT to treat worms on cabbages. But if they are in the heart of the cabbage they may be impossible to reach.

Bt works for the caterpillars (often called "worms") that come from cabbage butterflies (or any other caterpillars for that matter), but not for earthworms. I've never personally had earthworms bother my cabbage or other garden plants, but I imagine it would be possible for them to work their way into the cabbage plants.