Watering once or twice a week is best. Here are the guidelines for watering based on region and tree age.
Basic Summer Watering Chart: (80% of these rates for coastal schools)
▶ 1st year trees: 10 gallons per week.
▶ 4’ diameter canopy: 15 gallons per week.
▶ 5’ diameter canopy: 25 gallons per week
▶ 6’ diameter canopy: 30 gallons per week
▶ 7’ diameter canopy: 45 gallons per week
▶ 10’ diameter canopy: 80 gallons per week
How we got those numbers:
Inland Counties: Requirement in Gallons/week is about equal to canopy area. Example: A canopy with a 4ft diameter has an area of about 12.5 ft^2. (If you need a review on how this works, please see the math teacher down the hall). Thus this tree wants about 12 gallons/week. Add 20% if you are watering in the day time for evaporation loss.
Coastal Counties: Follow the same formula as inland, but use only 80% of the water. Example: A tree with a 4ft canopy diameter will want 80% of 12.5 gallons or about 10 gallons. Add 20% if you are watering in the day time for evaporation loss.
Spring and Fall:
50%-80% of the summer water amount.
If a fall fruit has already harvested, reduce down to 25-50%.
Check the soil under the mulch several times before leaving for Summer. Adjust water quantity up or down so that between waterings the soil is not wet enough to stain your palm, or dry as dust.
Don't let water stand against the trunk.... not good!
Fine tuning your watering amounts:
You can check the moisture level with a metal probe into the soil (e.g. straightened hanger). It should go down about a foot for your new trees. That means there is enough water at the root level. If it's too dry or too wet just prior to your irrigation, adjust the amount up or down by a gallon.
If the soil is Sandy or Sandy Loam, divide the total amount of water in two, and water twice per week. If the soil is heavy clay, once per week for the entire amount should be fine.