The sago palm tree is a living fossil. This species of tree first appeared on earth 350 million years ago and has outlasted the dinosaurs. Part of this plant's success is linked to its extremely long life. Even potted sago palm trees can live for hundreds of years. But there are some growing in the wild that are thousands of years old---much older than any palm tree. This is because the sago palm tree isn't a palm at all but a cycad, a close relative of the conifer.
Water your sago palm plant whenever the soil dries out. Established sago palm plants are quite drought-resistant and do not like continuously wet soil but appreciate the occasional long drink. Thoroughly soak the soil each time you water your sago palm.
Fertilize your sago palm plant once in spring and again in late summer with a balanced liquid commercial fertilizer. Follow the package's application rates for your plant's size. However, if your sago palm is only receiving partial sunlight, it should only receive 1/4 of the recommended fertilizer rate.
Ensure that your sago palm receives extra care when it is producing new leaves. This only happens once a year (if that). When it does, do not re-pot or otherwise disturb the plant at this time. The leaves are quite tender and will take several weeks to harden. The new leaves must receive good overhead light. If your sago palm is grown indoors by a window, turn it 1/4 turn every few hours so it receives even light and the leaves do not reach towards the light source. Do not allow the soil to dry out during this period.
Watch your sago palm's leaves for indications of its health and happiness. If old leaves turn yellow, your sago palm is likely receiving too much water or fertilizer. If new leaves turn yellow, the cause is likely under- or over-fertilizing. Prune yellow or brown leaves immediately. This will encourage your sago palm to produce more.
Prune you sago palm at least once a year. Get rid of the oldest leaves and any leaves that have browned or yellowed to encourage the sago palm to produce new leaves. Prune leaves as close to the trunk of the palm as possible.
Make sure your sago palm tree receives as much sun as possible---at least half a day's worth. If potted, your sago plant should be outside whenever the weather permits. Sago palm plants can tolerate temperatures as low as 30 degrees Fahrenheit and as high as 110 degrees Fahrenheit. Temperatures in the high teens can cause frost damage to a sago palm's leaves. When temperatures are forecast to drop below 30, move potted sago palm plants indoors.
Re-pot your sago palm when it outgrows its container. Cycads actually like to be root bound, so your sago palm's next pot should only be an inch or so wider than its root ball. Cactus potting soils work well for sago palm plants, but they can be grown in virtually any commercial potting soil mix.