In late spring, a mature male Sago produces a golden cone, shaped like a giant pine cone which may grow over 2' tall as shown in the photo above.  A female, shown below, produces a huge golden flower which slowly opens when it is fertile, then closes, and begins to produce viable seed if pollination from a male sago was successful. 

How can you tell if a Sago is male or female when it is young, or in a 6" - 17" (15 - 40 cm) pot at the Garden Center?  You can't.  Most Sagos must be at least 15 -20 years old before they are mature enough to bloom, and they also must be well established in your garden or landscape.  I've never seen one bloom in a pot.   How big is a 15 year old?  BIG!  Usually they will have an 10" - 14" (30 cm) diameter trunk and a leaf spread of 5' - 6' (2 m). 

In their native habit, Cycads are pollinated by wind or insects, however, in cultivation, they usually must be hand-pollinated for viable seed production.  In my South Texas greenhouse operation, 100 mature male and female Cycas revoluta - over 25 years old - are ground-planted as seed "parents".  Each year, about 30 males and females bloom and can produce more than 7,000 seed. 

You don't need a greenhouse operation to experience the fun of growing Sagos from seed, all you need is a male and female in your yard.  Or if you have one, perhaps a neighbor or friend has the other! 

In the Northern Hemisphere, Cycas revoluta ("King Sago Palms") begin to flower at the end of May.  Gary, our sago palm grower, and I check the blooming plants daily to determine when each is ready for pollination - timing can be somewhat critical.  The female flower will open when it is ready to receive pollen, and the male cone's "scales" will open to reveal pollen and have a sweet perfume odor.  At that point, we snap (or saw) the male cone from the center of the plant and shake it over the female.  A cone has plenty of pollen and can be used on several females at a time, or on one several days in a row.  The process is shown below:  
 

MALE SAGO FEMALE SAGO Male begins to form a cone. Female begins to form a flower. Male cone is reaching maturity.  Female flower opens. Male cone is shaken over female to release pollen. This should be done daily until the flower begins to close several days later. Female closes and begins to form seed during the summer months. Maturing seed will slowly turn from yellow to bright orange.

[Note: If you don't plan to use your male cone for pollination, then it can be removed, even when first starting to grow, without any ill effects to your sago palm.  There's no way to remove the female, but then the flower is rather pretty.  Usually they will not grow new leaves until the fall or following spring.] 
 

Note: I've had lots of emails asking which end of the seed to plant.  You plant sago seeds on their side.  To demonstrate this, take a handful, drop them on a soft floor and watch how they fall --  they fall on their sides just like if they fell out of a mother plant in the forest.  Only the top flat side of the seed should peek out of the soil.  Mother Nature usually covers them with falling leaves and natural mulch, but we'll have to improvise with a little extra soil almost covering them. 
 

Water the seed when the soil becomes dry about 1-2 inches down (3-5 cm). You do not want to keep them constantly wet, yet you do not want them to dry out completely.  Be sure to water the entire pool or pot thoroughly - we water ours once to "wet" the soil, then after the water has drained through, water them a second time to be sure the soil is completely saturated.  Do not rely on a dripper or mister system since those methods may not drench the soil properly. 
 
Seed usually put down a tap root and then the first leaf rises upwards from the same point.  The illustration shows how a "bulb" starts growing between the root and leaf.  This will continue to become larger as it becomes older. 
 
If we plant the seed in March or April, the first ones will usually began sprouting by the Forth of July.  If planted late in fall, it sometimes is spring before they come up. 
  
Usually, more than 90% of our seed sprout, although many other growers report lower figures.  It may well be that they are importing and using "old seed" from the Orient or Eastern Hemisphere or cracking open the seed before planting (which encouraged bugs to chew on ours).  Since we hand pollinate our Sagos, harvest them at the right time, store them properly, and plant within a few months after harvest, it gives us high success rates.  We also always include some extra "bonus" seed in our sales packets sold from the nursery. 
 

SEEDLING SAGO Cycas revoluta This 1 year old still has its seed attached. The small bulb is about 1/2" (1 cm) in diameter.  It sprouted during July and in January was moved to a  4" (10 cm) pot. The photo was taken when the seedling was a year old.