This section is from the book "The Gardener V1", by William Thomson. Also available from Amazon: The New Organic Grower: A Master's Manual of Tools and Techniques for the Home and Market Gardener.
The cracking of Melons is caused by keeping the soil too wet, especially after they are fully swollen. This sunless wet season has also had to do with it, and some varieties are more subject to crack under such conditions than others.
Rasps ought to do well with you on a north border - much better than in the garden quarter, where you say the soil is loose and light. Manure and work the ground well, and afterwards never dig, but spread the manure on the surface and merely fork the surface, mixing in the manure with the surface soil, but never disturbing the roots.