One of the most asked questions we get on the show each week during the gardening hour is, “How often should I fertilize my citrus trees, and when’s the best time of year.”

Ideally you want to fertilize three times a year. For an easy guideline to remember when, we’ve come up with these three dates for Arizona:

1. Valentine’s Day (Early spring, February-March)

2. Memorial Day (After the last chance for frost/late spring, April-May)

3. Labor Day (Late summer, August-September)

Now, this DOESN’T mean it HAS to be done on that particular day — but it gives you a parameter to use in planning.

Let me give you a “for instance” … let’s say Memorial Day is coming up in a couple weeks, but next week, we’re expecting a good chance for a rain storm. In this case, you’d want to fertilize the weekend before, so that the rain and moist soil will dissolve, disperse and nourish the tree to the fullest extent.

What’s the best fertilizer for my citrus trees?

Our Rosie Certified Partner, Harper’s Nursery, has always recommended using a balanced fertilizer that includes nitrogen, potassium and phosphorus — along with smaller included elements like iron, zinc and manganese.

The best way to judge this from the packaging is it will likely have three numbers, such as, “18-6-12″ which relates to its nitrogen, potassium and phosphorus content. If you’re in need of more fertilizer — head on out to Harper’s and they’ll take good care of you.

Lastly, always remember to follow the application directions on the packaging.

For more gardening and Do-It-Yourself tips, for your house, home, castle or cabin, visit every Arizona homeowner’s best friend: Rosie on the House. And be sure to tune in to KTAR every Saturday morning from 8-11 a.m. for the Rosie on the House broadcast!