It's not as hard as you think.

There are two good reasons for buying a Christmas tree with roots. First, you're too cheap to blow fifty bucks on a cut tree you're going to throw out in a couple of weeks. Second, you'd like to plant it in the yard where—if it survives—it will conjure up fond memories each December as you festoon it with lights that no longer work.

Let's be dishonest and presume you've chosen a live tree for the second reason. Having lugged the dang thing home—roots and dirt are heavy!—your primary task is keeping it alive, so it may fulfill its task once you plant it outside. Fortunately, Grumpy knows all about this and offers you the following tips (I refuse to use the word "hacks," as I am older than 24).

Select a tree that's adapted to your soil and climate.

Just because you can buy a Colorado blue spruce in Florida doesn't mean you can grow it there. Firs, spruces, and white pines don't like the South's long, hot summers and heavy soils. The only place you can grow a Fraser fir, the most popular Christmas tree, is in the mountains where it's native. Spruces tolerate a little more heat, but not much—like white pine, they do better in USDA Zone 7 and above. This means if you live in USDA Zones 8 and below, the only live Christmas trees likely to live very long include red cedar, Virginia pine, and Leyland cypress—not exactly top of the list.

Keep the root ball moist at all times.

But not sitting in a tub filled with water. (Roots, like you, need air.) If the roots dry out, your tree is history.

Don't keep a live Christmas tree in the house too long.

Sorry, but five days is tops. This is because the tree comes to you in its naturally dormant winter state. Leave it in the house too long and the heat will cause the tree to wake up and start growing. Then it you plant the tree outside and a freeze hits, the sudden cold will kill it. In addition, live Christmas trees need sun.

WATCH: How To Choose a Christmas Tree

If you're determined to buy a live tree, the photo above shows a smart way to do it. Buy a small tree in a one or two-gallon pot that you can decorate and display on a tabletop, windowsill, etc. Then after your five days are up, move the tree out to the porch or patio for the winter. Dwarf Alberta spruces, the trees in the photo, are excellent candidates, because they come in small sizes, grow very slowly, sport the traditional Christmas tree shape and needles, and grow as far south as USDA Zone 8A. They're quite cold-hardy too. Water the pots once a week.