Q. A few months ago you had an article about grapes not
growing to normal size. You stated the soil in Southern Nevada lacked a certain
hormone that the grapes required. My Thompson vines grow like weeds but the
fruit is the size of peas.
growing to normal size. You stated the soil in Southern Nevada lacked a certain
hormone that the grapes required. My Thompson vines grow like weeds but the
fruit is the size of peas.
A. The hormone is not in the soil but manufactured by the
plant. Purchasing and applying this hormone is one of three methods that can be
used to encourage larger berries.
plant. Purchasing and applying this hormone is one of three methods that can be
used to encourage larger berries.
The
application of this hormone to grapes is permitted for organic production in
most cases. However, there are two other methods that will enlarge berry size
without the application of this hormone.
application of this hormone to grapes is permitted for organic production in
most cases. However, there are two other methods that will enlarge berry size
without the application of this hormone.
These
other two methods follow the same principle used for producing larger fruit in
tree crops: remove fruit from the plant so the remaining fruit becomes larger.
This totally organic practice is called “thinning”.
other two methods follow the same principle used for producing larger fruit in
tree crops: remove fruit from the plant so the remaining fruit becomes larger.
This totally organic practice is called “thinning”.
 |
| Pinching the bottom third off of the bunch |
When berry
clusters or bunches first emerge in March or early April, thin or remove bunches
so only large ones remain spaced no closer than a foot apart. Remove small
bunches totally.
clusters or bunches first emerge in March or early April, thin or remove bunches
so only large ones remain spaced no closer than a foot apart. Remove small
bunches totally.
Second,
when grape individual berries are about the size of a BB, pinch off the bottom
third of the bunch. Bunches of grapes are normally triangular in outline.
Pinching the bottom third of the bunch produces a harvestable bunch that is
round in outline with much larger berries.
when grape individual berries are about the size of a BB, pinch off the bottom
third of the bunch. Bunches of grapes are normally triangular in outline.
Pinching the bottom third of the bunch produces a harvestable bunch that is
round in outline with much larger berries.
After
those practices have been followed, you can use a plant hormone called
gibberellin to increase the berry size artificially. This is not a natural
process but you are basically giving the berries a “kick in the
pants” to get them to elongate more than they would normally.
those practices have been followed, you can use a plant hormone called
gibberellin to increase the berry size artificially. This is not a natural
process but you are basically giving the berries a “kick in the
pants” to get them to elongate more than they would normally.
Warning.
Don’t expect gibberellin alone to do the work for you. You must also thin out
your grape bunches.
Don’t expect gibberellin alone to do the work for you. You must also thin out
your grape bunches.