Spring blooming bulbs like tulips and daffodils can be planted from mid-October until the ground freezes. Gardeners sometimes aren’t sure how deep to bury them. Even when they know, if the soil is compacted and hard to dig, the tendency might be to give up too soon and just get them barely interred.
Why is it so important to nestle them in at the correct depth? You want to protect the bulbs from temperature fluctuations. In our temperate climate, we have high heat, bitter cold, and winter temperatures that jump up and down the thermometer. Also, anything too close to the surface is in danger of popping out due to frost heaving. Think of the soil as a protective insulating blanket. Reason number two? The roots will anchor the plant in place, providing stability in our constantly windy spring climate.
That brings us to the correct planting depth. Of course, it changes depending on the plant. Most packaged bulbs will come with depth instructions. Many of the mail-order companies send a booklet with your order showing the correct number of inches for all bulbs. If you purchase loose bulbs or get some from a friend, the accepted rule is planting a bulb two to three inches times the bulb’s height.
So, which is it, two or three? The answer depends on your soil. If you are planting in clay or poor draining soil, stick with the shallower two inches times the height to counteract rotting problems. However, when the soil is lighter or friable, choose the deeper three inches times the bulb height. This helps the roots access water.
Daffodils will return more reliably year after year than tulips. In fact, public gardens treat tulips as annuals and dig up the entire display in late spring, plant summer annuals, then plant new tulip bulbs each fall. Most home gardeners hope to get more than one year from their spring display. Try these tips for multi-year color.
Plant species tulips. They are a specific type and are more reliable than the hybridized tulips. If buying from a catalog, look for varieties that include mention of them as repeat bloomers. Plant tulips where they won’t get a lot of supplemental watering during the summer. Design advice is to plant tulips mixed in with perennials so that as the perennials grow, they hide the spent tulip foliage. That is a good design tip, but the water needed by the perennials all summer is not good for the tulip bulbs. Finally, do not remove the leaves until the green has disappeared. They are needed to build energy in the bulb for next year’s display.
Call 217-465-8585 or email schiver@illinois.edu to connect with Edgar County Master Gardeners.
Illinois Extension leads public outreach for University of Illinois by translating research into action plans that allow Illinois families, businesses, and community leaders to solve problems, make informed decisions, and adapt to changes and opportunities. Illinois Extension is part of the University of Illinois Urbana-Champaign College of Agricultural, Consumer and Environmental Sciences.