Here in the low desert of Phoenix, citrus is fertilized three times a year. I use an easy way to remember when to do it using holidays: Valentine's Day, (February), Memorial Day (June), and Labor Day (September).
Recent research from the University of Arizona demonstrates that fertilizing newly planted citrus is unnecessary. Wait until your tree has been in the ground for two years before applying fertilizer.
Nitrogen is the element that established citrus trees need the most and it is responsible for assuring a good fruit crop and a healthy tree. Feeder roots are located just below the surface of the soil, so it is important not to over fertilize, which could burn these tender roots. The amount of fertilizer you use will vary according to the age and size of the tree, and in some cases the variety of tree. Established grapefruit trees only need one-half the amount of fertilizer normally given to other varieties of citrus. Use this chart to determne how much to use.
Water the tree the day before, broadcast the fertilizer over the root zone and water in well. Remember to water deeply-at water should seep down at least 3 feet! This may mean using a house with a slow trickle for several hours. Test the depth with a metal rod. It will stop when it reaches the hard dry ground!
You can purchase citrus fertilizer at almost any garden center, however I prefer to get mine at a private nursery. I also use Soil Secrets to build the soil so the tree can take up the nutrients easier. Read more about Soil Secrets below.
Don't expect much fruit production for the first two to four years after planting. Some trees on slower-growing rootstocks may take five or six years to produce a bountiful crop.
Doreen Pollack is the Garden Goddess and owner of Down 2 Earth Gardens, providing garden consultations and coaching. Join her for gardening tips at monthly workshops or schedule a home consultation. To find a workshop near you, visit www.down2earthgardens.com or call 623.217.6038
