These articles are written to apply to the northeastern corner of Illinois. Problems and timing may not apply outside of this area.
Plant Spring Flowering Bulbs This Fall
September 7, 2000
Fall is a good time for planting in the home landscape. One big group of plants for fall planting are the spring-flowering bulbs, including crocus, tulips, hyacinths, and daffodils. Follow a few guidelines to assure showy blooms each spring.
Probably the biggest secret to success with spring bulbs is good soil drainage. Few bulbs will tolerate sitting in excessively wet soil for prolonged periods of time. Improve drainage by adding organic matter to the soil prior to planting the bed this fall. Avoid low areas known to collect and hold water. Consider raised beds as a possibility in marginal areas.
Rodent and squirrels can be a problem by digging up or damaging newly planted bulbs this fall. Cover planting areas with fine wire mesh to help prevent damage.
Most bulbs have energy stored and buds formed before they are planted, so are likely to produce the first spring after planting. For repeated quality and productive blooming, fertilize the soil prior to planting, using a complete fertilizer such as a 5-10-5 or 5-10-10 at a rate of about one pound of fertilizer per 100 (10 by 10-foot) square feet of planting area. Work this into the upper 46 inches of soil.
Bulbs fertilized will start showing improved growth and flowering the second season and beyond. Next season apply about two pounds of the same fertilizer per 100 square feet when the bulbs are in bloom to the upper inch of soil.
After bulbs have bloomed the first season after planting, there are some factors that influence how likely they are to continue blooming each season. One is how long the foliage is left after blooming. Wait until leaves yellow before cutting them off to assure the plant has had time to produce food for the next season. Another problem can be deep shade; which can limit growth and lead to fewer and fewer flowers each year after.
Bulbs may also get overgrown and crowded over time and require dividing.
Dig them up, divide them, and then replant. Discard bulbs showing signs
of rot. Given a choice, the best time for this would be in late spring
or early summer after the foliage has yellowed. Larger bulbs will flower
the following spring, whereas smaller bulbs may not until the second year.