Was looking through a vineyard and noticed that the grapes were beginning to show up on the vines. They were small and unrecognizable from when they would be picked but they were the first sign of fruit on the vines. What is this called? Basically, what is the term for when fruit first starts to appear on a plant?
Set is the verb.
(Of fruit) develop from blossom:
'once fruits have set, feed weekly with a high potash liquid tomato fertilizer'
The stage of fruit set follows flowering almost immediately, when the fertilized flower begins to develop a seed and grape berry to protect the seed.
Following fertilization, the fruit begins to form.
How about fruit, the verb?
The grapes are beginning to fruit
I would say that the vines are budding:
bud, v.: To put forth or produce buds
bud, n.: A small protuberance on a stem or branch, sometimes enclosed in protective scales and containing an undeveloped leaf, flower, or leafy shoot.
As you can see, this does not necessarily refer specifically to fruit, but is widely understood to be when any plant starts to produce growths.
Alternatively, you could refer to them as being in bloom, in blossom, or blossoming, all of which refer to the flowers of the plant that produce the edible fruit.
On apple trees this is sometimes referred to as 'petal drop', 'petal fall'. The flowers of course are much smaller on vine clusters.
On apples and grapes they refer to the fruit 'setting'. Clement Hoare Cultivation of the vine:
July 1st: The blossoming being now nearly over, the berries will be setting in rapid succession. As soon, therefore, as they have all grown to the size of very small peas, an estimate must be made ... of the weight etc..
Usually when we talk about vegetation beginning to grow, or anything that has just started growing, we say it's 'sprouting', or that it is a 'sprout'.
: to produce new leaves, buds, etc.
: to grow or develop (something)
: to appear suddenly and in large numbers
Though it's usually used for thin vegetation, or for a newly-growing plant, you could say that the fruit is 'sprouting' from the tree, or call each individual fruit growth a 'sprout'.
- A condition or time of flowering.