SPLITTING CHERRIES CAUSED BY WATER PENETRATING SKINS

Apparently the reason for cherry splitting has less to do with the uptake of moisture from the roots than moisture (rain or hosepipe water) falling on the actual skin of the cherries. Cherries are like balloons.  They begin as small, green, embryo cherries and the pit (or seed) develops while they are still small and green.  Then the cherry begins to swell quite rapidly.  The amount of skin it starts off with remains the same and as it stretches the skin becomes thinner, developing microscopic cracks which allow moisture to enter.  It is the moisture entering these tiny cracks which softens the protective skin and allows the skin to split. 

Prunus avium 'Stella' Gisela 5 sweet cherries splitting

Some types of cherries are more prone than others ('Bing' is prone, I understand) and this is the first year that I have seen this happen to my 'Stella' cherries.  The first year that I had the tree, the first small crop it produced didn't exhibit this problem at all.   By the way, Gisela 5 is a dwarf tree and I grow mine in a large container which is sunk into my garden border for stability. 



What can we do about it?  Well, we can put a canopy over the tree to protect the fruit, or we can grow cherries which are less prone to splitting.  I would say that less than 10% of my fruit has cracks in it and they are still edible.  At least, I've eaten the least damaged of them and I'm still breathing. 



On a final note, I understand that cherries do not continue to ripen once picked so be warned.  If you go out and pick all the fat but unripened cherries, thinking you will ripen them indoors, you might just be shooting yourself in the foot, so to speak.