Damsons

One way of knowing the fruit are ready is to put a blanket/sheet under the tree and give it a good shaking. If the fruit drip off then they are about ready. But this technique is only any good if you are ready to make jam or bottle the fruit as it will bruise easily and won't keep after this method of picking. Jnelhams has described the proper way of [font=verdana,arial,helvetica]gently cupping the ripe fruit in your hand and pressing the dip at the top to release it. If the fruit does not come away readily, it means it isn’t ripe so don’t force it. Take care not to pull the fruit leaving the stalk behind as it won’t last as long without it.
Damsons can be eaten raw so it's quite easy to taste them to find out if they are ripe enough.
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