is there a compost i can grow then dig in

It is called Green Manure. Basically its a plants e.g. mustard. Types of clover.
You can buy the seed from garden centres. Sow now and let it grow. It will take up the nutrients from the soil as it grows over summer holding it in the plants rather than the nutrients being washed away or lost from bare soil. Then it can be dug in roots, shoots and all which basically 'puts the nutrients back' into the soil and also you digging it helps improves the texture/structure. The veg growing can continue as normal later in the year.
Ask about it at garden centres.

At this time of year you should sow Phacelia. Not only will it grow easily from seed but by the time you get back from the school holidays you might have some lovely purple flowers covered in bees and other insects.
It's easy to pull out and dig in whether it's in flower or not, though unlike clover it doesn't put nitrogen into the soil. But a lot nicer than mustard!