Soil . The beds are only small , but are you fit and ok to dig ? I assume yes .
Try to double dig if you can . This is done by digging a trench one spade deep across one end of a bed . Place the removed soil at the other end of the bed .
Now , i use a fork , turn over the bottom of the trench and mix in well rotted manure @ 2 buckets to a sq yd .
Then , moving along the bed , dig another trench next to the first one , placing this soil ontop of the first one .
Dig the bottom of trench 2 and mix in more manure .
Continue along the bed till you reach the last trench , then once you have dug the bottom and added the manure , place the saved soil , from the first trench , ontop . Job done .
A 4 year rotation is just a way of growing veg to avoid pest and disease build up by growing the same family of veg in the same spot , year after year . If i try a complete explanation here it wil take me hours , i am using a mobile phone to connect !
A good example of what to do is at ;
www.gardenaction.co.uk then search for allotment rotation .
You can get winter hardy white lisbon spring onions now from
www.dtbrownseeds.co.uk . These can be sown through till october , as can guardsman .
Check with your friend regarding manure , for when there is likely to be wormer or other meds in it , what goes in the horse , comes out ! And what goes into the soil goes into your veg !
Don't manure the root bed , carrots , parsnips , onion , garlic , leek etc , but you can mix in a bag or two of cheap potting compost to help with soil structure and plant feeding .
If you add a lot of peat , you may need to check the ph after a few weeks or so . Then adjust accordingly with some lime .
Keeps you busy eh ?