A better choice is terra cotta or ceramic, both of which will breathe, and allow moisture to escape. Regardless of the material, though, you need to make sure your containers have enough drainage holes. Don’t be afraid to add more if you don’t think there are enough. Even if your containers are new, it’s probably a good idea to wash and sanitize them first. This can help prevent diseases like tulip blight from spreading or carrying over from one growing season to the next. A weak bleach solution should be enough to kill most any fungus or bacteria present. Be sure to rinse containers thoroughly after washing. In order to keep your soil from leaking out through the drainage holes in the bottom of the container, you’ll want to add about an inch of gravel or pottery shards before filling your container.
Make sure your gravel or broken pottery has been washed and sanitized as well. Next, fill your container to the proper level with good quality potting soil. If you choose a soil specially formulated for growing tulip bulbs, you won’t have to add more soil amendments. If you are using a general purpose potting soil, adding some bone meal or bulb fertilizer at this point will help ensure a bountiful tulip crop. You might also want to add a layer of coarse sand at this point. Tulips hate being too wet, and the bulbs will quickly rot if the soil isn’t well drained.
Adding a layer of sand helps keep your bulbs on the dry side, just the way they like it. Inspect your bulbs carefully for soft or discolored spots. Discard any bulbs that seem damaged or bruised, have missing tunics (the papery bulb covering), or feel completely dried up. Tulip bulbs should feel heavy for their size. Place your tulip bulbs with the point facing upwards and the root, or basal, end in the sand. Refer to the planting instructions for your bulbs to determine how far apart to space them. Tulips tend to look best when planted in uneven numbers, between five and fifteen bulbs per pot. Completely fill your container with soil and water well.
Containers should be stored for the winter in a protected place, such as inside a shed or garage. If you live in a particularly cold area, however, you might want to let your tulips overwinter in a basement or root cellar. It’s important for tulips to have six to eight weeks of temperatures below about 50 degrees Fahrenheit. Bring your tulip containers out in the late winter, about the time you’d start looking for signs of life from your perennial garden.