Planting spring flower bulbs is fun and easy. The three most important points that you should know about planting them are:
- Setting the bulb at the correct depth
- Making sure to place the bulb right side up in the hole
- Proper planting time, which is based on your regional location
Planting Depth
The chart below shows the recommended planting depths and proper positioning for common spring bulb types.
Bulb Position
Remnants of roots on the bottom of the bulb should tell you which side of the bulb points down. If you see no sign of root remnants, plant the bulb so that the most pointed, narrow part points up.
Best Planting Time
While bulbs sellers offer and/or ship daffodils, tulips and other spring flowering bulbs anywhere from August through October, this might not be the best time in your region to plant the bulbs.
If you garden in a cool climate such as in USDA Zones 3-8, spring flowering bulbs can be planted anytime in the fall after temperatures cool down, but before the ground freezes if you're in northern zones. Your bulbs need to establish strong root systems before winter sets in.
If you live in a warm climate where air temperatures don’t fall below freezing, bulbs, with the exception of daffodils, will require some pre-cooling before planting. You can store them in a refrigerator for about 6 to 8 weeks, even longer if necessary, in a mesh bag such as what most bulbs come packaged in from a nursery. Be careful not to store bulbs with fruit in the refrigerator, especially apples, because the ethylene gas given off by ripening fruit will kill the flower inside the bulb.
Here are the best planting times for spring flowering bulbs for all US Regions:
Northeast and Rocky Mountains: Plant September until the ground freezes
Midwest, Appalachians, Mid-Atlantic Coast, and Plains States: Plant September 30 through November 30
Pacific Northwest Coast: Plant October through December 1
The South: Plant October through December 15
Gulf Coast: Plant October through December 31
California Coast: Plant Mid October through January
What's Your Style?
The planting method and type of bulbs you choose can depend on the design style you want to achieve: natural or formal.
Natural
Regarding bulbs, the term "natural" usually refers to the ability of some bulbs to come back year after year. In naturalistic design, you do your best to imitate a natural planting for a particular type bulb. You might simply walk along a woodland border tossing bulbs here or there and then plant them where they land on the ground. Once planted and up and growing, natural bulbs, such as Daffodils, will go on to naturalize on their own into a larger patch.
Formal
In formal design, it's unlikely you will need or want bulbs that come back every year. Formal designs often use bulbs in densely packed groups or rows, or combined with annual bedding plants in flower bed.
Planting Bulbs
When planting bulbs, keep in mind that most bulbs do not like constantly soggy or wet soil, which can and often will rot the bulbs. So plant bulbs in sites with well-drained soil.
Step 1
If you are planting many bulbs that will be grouped together in a mass or row, dig one long trench or wide hole at twice the depth you intend on planting the bulbs. Place the soil beside the trench or hole, or in a wheel barrow or on a tarp. If you're design is a natural one, and you'll be planting bulbs individually where they were placed or landed, dig a planting hole 6 to 12 inches wide and twice as deep as as you intend on planting the bulb. The wider the hole the better, especially if you're planting perennial bulbs that will multiply and spread over time.
Step 2
If the soil you remove from the planting trench or hole is hard-packed or of poor quality, condition it by mixing in a compost, such as mushroom compost, composted manure, or your own home-made compost. You may also mix in some bone meal to your soil mix. Refill the hole to the halfway point with the amended soil mixture.
Step 3
Place and space the bulbs in the planting hole as directed on the package. Make sure to use a ruler to achieve the proper planting depth for the bulb type(s) you are planting.
Step 4
Backfill your trench or hole with the remaining soil mixture, tamping lightly as you go.
Step 5
Apply bulb fertilizer over the planted area and a layer of aged wood mulch or pine straw.
Step 6
Water bulb planting thoroughly to a depth of at least 8 inches.
Fertilizing Flower Bulbs
When you purchase bulbs from a nursery, everything a healthy mature bulb needs to produce a flowering plant is in the dormant bulb following its harvest by a reputable bulb grower. However, fertilizer may be necessary for the future success of bulbs that are meant to perennialize (return for several years), depending on your soil fertility.
Soil pH
It's a good idea before planting bulbs, or any other plants, to test your soil pH. You can do this simply with a soil pH testing probe. Doing so will help you to know which if any nutrients or minerals need applied to grow certain types of bulbs that might have specific pH requirements. Or you can use this information to select only bulbs that like the conditions of your soil as it is.
Fertilizer
Although fertilizer suggestions for bulbs vary between authorities, current recommendations are to mix a slow release bulb fertilizer into the top few inches of soil once a year. The NFBIC recommends fertilizing in the fall when the bulbs are putting out new roots which will readily absorb nutrients. A fall top dressing of well rotted manure or compost annually is also beneficial. If fertilizer must be applied over bulbs in the spring, try to make the application as shoots emerge (after the soil has thawed). It is not as desirable to fertilize spring flowering bulbs too close to flowering time or too long after bulbs are finished flowering. As spring flowering bulbs go dormant for summer their roots die back and cease nutrient uptake until the soil cools in the fall and starts the cycle over. Whichever product you choose, follow the recommended application rates on the package.
Organic gardeners may choose to apply cottonseed or blood meal for nitrogen, greensand for potash (potassium) and bone meal for phosphorous. Bone meal is not a complete bulb food and modern processing methods leave it low in nutrients, so it is not recommended for use solely as bulb fertilizer.
Application
The application of fertilizer to bulb plantings is best done as a top dressing. To avoid burning a bulb or its roots, never mix fertilizer or fresh manure into the planting hole with the bulb. The high concentration of salts in some forms of nitrogen can desiccate plant tissue if it makes direct contact. The newly emerging roots on a bulb are very sensitive to these salts; death of the roots will result in bulb failure.
Pruning Bulbs
There's really not much to pruning spring flowering bulbs such as daffodils and tulips.
Here's all you have to do:
- Avoid removing foliage from spring flowering bulbs after they have bloomed. Foliage should be allowed to die naturally since it sends nourishment back into the bulb for the next year's growth and flowers.
- If foliage is long enough after blooming has finished, try tying it in a knot. This helps to keep it more attractive until it dies completely.
- After foliage has died completely it can be removed.
That's about it!