Apple Thinning Tips & Timing

Sevin® is registered for apple thinning and may be used to chemically thin apples for increased quality, but label directions must be carefully followed. Many factors influence the degree of thinning achieved. Timing of spray, tree age, variety, nutrition, previous crop load, pruning, the degree of bloom set, weather and the use of other chemical thinners are all factors to be considered. When any of these favor reduced fruit set, caution should be observed in applying SEVIN so that excessive thinning and unwanted yield reductions do not occur.

Lime-Sulfur Solution™ for use as an apple thinner is authorized in the state of Washington (EPA FIFRA 24C registration).  Click here for a copy of the 24C outlining the limitations of this use.

Application Tips and Timing For SEVIN

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  • Apply between 80% petal fall and 16 mm fruit size under ideal conditions or approximately 10-25 days after full bloom
  • For most consistent thinning effect, apply Sevin when daytime temperatures will be above 70⁰ F (21⁰ C) for three days and during period when foliage remains moist for 30 minutes.  Application when temperatures exceed 80⁰ F (27⁰ C) may result in over thinning.
  • Early morning is a good time to spray when temperatures are climbing and trees are becoming physiologically active
  • Evenings are also good because trees remain wet longer and, in most conditions, will dry as the next day begins
  • Apply varieties vary in their response to thinning applications of Sevin. Experience in the orchard and consultation with local experts are invaluable to achieving the desired outcome
  • Observe label precautions to protect pollinators.  Click here for more information.
  • Always read and follow label directions
Apple Thinning Information Sheet ›