1. Timing: the later the better.
Although they delight us in March and April, Spring bulbs must be planted in the Fall— between Halloween and Thanksgiving in the Philadelphia area and similar climes. (That means AFTER Halloween, oh you with itchy planting fingers.) Plant them earlier and they might sprout prematurely, thus ruining the Springtime show. (Unless we're talking about grape hyacinth or one of the other weirdo bulbs that normally sends up shoots in the Fall.) South of Philly, wait until Thanksgiving. North of Philly, sometime in October. When exactly? The ideal is to get the bulbs in the ground with about a month to go before the soil freezes hard for the season, but not much longer.
2. Jam 'em in There!
Spring bulbs tend to look their best when crowded and planted in bulk. Yes, it can be very nice to see the random tulip coming up here and there, and if that's your idea of a good time, go for it. But if you want a real show, plant a tight drift of dozens of the same type; a hundred if you've got the room. If you're going to lift and store them for the summer (see # 9 below), they can touch. If you plan to leave them in the ground to multiply for you over time (you dreamer, you), leave a bulb or two's worth of space in between each bulb.
3. Observe the Depth Chart.
Plant twice as deep as the bulb is high. In other words, you should be able to fit another bulb on top of the buried one. But don't do that; use dirt instead.
4. Wait to Feed.
You'll see a lot of advice to dump fertilizer in the hole when you plant, which is curious because these bulbs are just going to go sleepies for several months and will not be able to use any food. And besides, the following year's flowers are already formed deep inside the bulbs. (Cut one open and check it out; this makes a great 'show and tell' for school children, television reporters and other impressionable people.) The time to feed is NEXT year—after the flowers have faded. That'll grow a new flower that will sit inside the bulb waiting for its Springtime cue.
5. But do plant in good soil.
Bulbs like a nice, light, naturally rich soil in which to spread their little rooties and hide from winter. If your soil is nasty clay, excavate an area, toss away the worst of the clay and add lots of nice yard waste compost. If it's sandy, just mix in lots of compost; your soil already drains well, and all it needs is some substance—like me.
6. Clean up your trash!
Squirrels are notorious for digging up and gastronomically enjoying the tastiest bulbs of Spring—namely tulips and crocus. So after you finish planting, be sure and clean up every piece of 'bulb trash' from the area; those brown outer wrapper pieces are like a neon sign saying: "Yoo, Hoo! Squirrels—dig here!" I also spray deer repellant over the area after planting; it disguises the scent and makes digging unpleasant for the little varmints. If you live in an area plagued by gophers or have lots of voles, bury tulips and other edible bulbs (see below) inside little cages of hardware cloth; use a wider mesh on top so the sprouts are unimpeded.
7. Or just plant daffodils.
Those giant yellow blues-chasers of Spring taste nasty. If the nasty taste doesn't deter underground attackers, they're poisonous. So there. Daffodils have no downsides; they're VERY reliable returners, completely pest proof, and brighten up the month of March better than a spotlight. Nothing bothers them either—or did we say that?
8. Wait to mulch—if at all.
To say that Americans have gotten mulch happy doesn't begin to describe the madness that has attacked our landscapes. "Mulch" (which means anything that covers the surface of the soil to prevent weeds and maintain moisture, and is NOT a synonym for shredded wood, bark or chipped-up pallets from China spray-painted some God-awful color) is largely optional in the winter. Winter mulch mostly prevents bulbs and such from heaving up out of the ground in areas where there's a lot of freezing and thawing. So if you want to mulch to prevent your bulbs from popping up to say hello in January, do so after the soil freezes hard the first time. No; mulch does NOT keep your little bulbies—or anything else—warm over winter. It keeps the soil temperature evenly cold, thus preventing that soil from warming up on sunny days. Do not mulch if you have vole problems; these underground eaters love the protection from predators it affords. Shredded leaves—NOT whole leaves—make the best mulch. Shredded wood, bark and dyed mulches are the worst. (If these wood and bark revelations are a mulch epiphany for you, go to the letter 'M' in THESE ARCHIVES and get yourself learned real good.)
9. Plan to lift next Spring.
When Spring bulbs fail to return, the cause is often planting annual flowers over top after their season is over. This appeals to us, but works against the genetics of the bulb, whose native summers are intensely hot and dry. The easiest answer is to wait until after their green leaves have turned brown, then lift and store them for the summer. Read this Previous Question of the Week for all the details.