Peach Tree Dropping Fruit

Q. I have a well-established, prolific peach tree. About this time every year it loses some of its immature fruit and I know that is normal. However, this year it's losing an abundance of fruit. I'm literally picking up 50-100 peaches a day. I have checked the irrigation and it seem to be fine. (drippers, 15 min per day, twice a day.)

A. I don’t like that you are applying water every day, twice a day in fact! Is there any way that can be changed to less often? That irrigation frequency sounds like watering a lawn or vegetable garden when it’s hot and windy out! I don’t know about the amount you are applying, but you are applying water way too often.

Peach trees will probably set less than 5% of the fruit that results from flowers. If you don't remove the fruit, the tree will do it for you. The end result is, what are the size of the peaches when you harvested? And how did they taste. Far more important to consider than fruit drop. Also, letting the soil become too wet or too dry will encourage fruit drop and loss. Change your irrigation practices!

What's Happening? 

Fruit trees should have water applied to them twice a week in May when growing alone in the desert and in most soils. The applied water should wet the roots to a depth of about 18 inches each time its watered.  

Sometimes people will ask me...how much mulch or woodchips should I have around my trees? Its like asking how far should you keep weeds from growing near a plant. The futher, the better for weeds. For mulch, at least to the dripline of the tree. But further is better!

For fruit trees growing in the desert, I like to see a layer of woodchips on the soil surface 3 to 4 inches deep. These woodchips provide a layer that protects the roots from getting too hot, conserves water, prevents most weeds from growing and helps keep the soil dark and rich.

Only a few months after applying wood chip mulch to the soil surface in the irrigated area you will see the color of the soil become darker. This is from the decomposing wood chips covering the soil. It decomposes and adds organic matter to the soil and you see worms flourish in those areas.

            I imagine the tree roots  are only growing about 2 inches deep if watering is this often. They should be growing 18 inches deep to anchor the tree in the soil. Roots like this are cycling back and forth between too dry, too hot or too wet. Roots can’t grow deeper because they are drowning (if you are watering a lot) or getting too hot and dry (if you aren’t watering enough). I need to know how many gallons you are applying, not the minutes, and where it’s being applied.

What to do? 

Cover all the soil under the tree’s canopy with 3 to 4 inches of woodchips. Apply water to the soil 12 inches from the tree trunk all the way to the edge of the canopy. This can be done by constructing a donut around the tree trunk 6 to 8 feet in diameter.

Irrigation donuts or moats around trees when they are small, are smaller. As the tree increases in size, the donut increases in size as well.

            Fill the inside of this donut with a 1-inch layer of compost with woodchips on top. Fill the inside of this donut with water once a day. At the end of August, begin watering every other day. At the end of September water every third day. By December you should be watering once a week.