How To: Trench Planting Spring Blooming Bulbs

by Wendy

Trench planting is a quick, efficient way to plant flower bulbs for hundreds of spring blooms with minimal effort.

If you’ve ever visited a botanic garden in early spring, you’re sure to have seen brilliant swaths of blooming Tulips, Daffodils and Hyacinth.

You don’t need a horticultural staff to get this look in your own yard. By trench planting spring-blooming bulbs, you can easily get 100 bulbs planted in under an hour. With just a little time and planning, you’ll have a wonderful spring gift awaiting you.

Trench planting bulbs in 6 simple steps:

1. Choose your bulbs. We suggest planting at least 100 blooms for a big impact.
2. Dig a trench to the right depth for the flower bulb you’ve chosen, between 4-8” deep, depending on the required depth of the bulbs, which will be noted on the bulb packaging. If your soil is hard to dig, you can create a raised bed for bulbs.
3. Place the bulbs in the trench, pointy side up.
4. Cover with soil.
5. Water thoroughly to get rid of any air pockets.
6. Come spring, you’ll be greeted with bright cheery blooms.

You can make a big impact with a small area. A 1 ft. x 5 ft. planting area can be dug quickly, usually in 10 to 15 minutes, but is large enough to give you a beautiful swath of bright blooms in spring.

If you want a little more guidance, we’ve asked our bulb experts for their advice.

Choose all one type of bulb in multiple colors for a cheery look.

11 Tips For Choosing Fall Bulbs For Trench Planting

1. Choose bulbs for your zone

Tulips, Daffodils, and Mini Iris are among the most cold-hardy bulbs, and are typically cold hardy in zones 3-7. These bulbs require a dormancy period provided by the cold temperatures of winter.

If you’re in a warmer area, zones 8-10, choose Allium, Crown Imperial (Fritillaria), Wand Flower (Ixia) or Spider Lily (Lycoris).

2. Select fall-planted bulbs that bloom throughout the spring season.

Choose wisely, making sure you have early-spring, mid-spring, late-spring blooms.

• Early Spring-Blooming Bulbs include Crocus, Mini Iris and Wildflower Tulips. Crocus, Spring Starflowers, and Snowdrops pop through the snow in early spring.
• Mid Spring Blooming Bulbs include Grape Hyacinth (Muscari), Hyacinth, Darwin Tulips and Daffodils.
• Allium are perfect for Late Spring Blooms.

Or, choose a fall bulb mix - these are generally designed to bloom throughout the season. 

3. Plant bulbs where you can appreciate them

If you’re using small bulbs, be sure to place them near a walkway so that you can appreciate their delicate blooms. Use larger, bolder-blooming bulbs if the planting will be viewed from a distance.

4. Make sure you have enough bulbs

Based on the garden area, you’ll want to plant bulbs at the right density per square foot, depending on bulb size.

• Smaller bulbs, such as Crocus, Grape Hyacinth (Muscari), and small blooming Allium, are around 16 bulbs per square foot.
• For larger bulbs, such as Tulips, Daffodils, and Hyacinth, typically 6 bulbs are planted per square foot.
• Some large bulbs--Globe Master Allium and Crown Imperial (Fritillaria) for example--are planted with as few as 3 bubs per square foot.

We note the recommended bulb spacing on every variety we sell, both on our website and the bulb packaging.

Daffodils and Grape Hyacinth combine beautifully.

5. Make planting easy

Choose bulbs that have the same planting density and planting depth. If you want to easily combine bulbs, choose from Crocus, mini Daffodils, Grape Hyacinth (Muscari) and Mini Iris, as most are planted with 16 bulbs per square foot and 2-4” inches deep. Or choose several varieties of Tulips that bloom at different times, but need a planting depth of 6-8” inches.

6. Include some perennial bulbs

If you choose spring-blooming bulbs that are good for naturalizing, it means they are perennial bulbs and will multiply and spread. You’ll plant these bulbs just once, but enjoy them more year after year. Good naturalizers include Glory of the Snow (Chionodoxa), Grape Hyacinth (Muscari) and Wildflower Tulips. To ensure reblooming, fertilize after blooming each year with a 3-5-3 fertilizer.

7. Pick pest-resistant bulbs

If you have deer or other pests such as squirrels and voles, choose pest-resistant varieties such as Daffodils, Grape Hyacinth (Muscari), Fritillaria, and Hyacinth. Planting strong-smelling Fritillaria amongst Tulips will often deter pests from Tulip bulbs, which are not pest resistant. (Note: Wildflower Tulips are deer resistant!)

8. Make a statement with a monochromatic bulb planting

People will notice your bulb planting from hundreds of yards away if you stick to one color. You can accomplish this in several ways. Try planting all Daffodils, but choosing varieties that will bloom at different times. Or, create a pleasing purple palette by choosing purple Crocus and Mini Iris for early blooms, Tulips, Grape Hyacinth and Hyacinth for mid-season blooms and Allium for late season flowers.

Be sure to place the bulbs closely to one another to get a high impact look. 

9. Plant bulbs in layers for a “bursting with blooms” look

You can mix bulbs that require different depths. Dig the depth of the trench to the needs of the deepest bulbs (12” for large Daffodils). Plant those that need the greatest depth first. Add a few inches of soil and add another layer of bulbs that have shallower planting depths.

10. Plant spring-blooming bulbs in your lawn

Remove the sod before trench planting, then lay it over the planted area again. Make sure to account for the depth of the sod when digging your trench. Bulbs will poke through the lawn and bloom in spring-time. After your bulbs have gone dormant (a few weeks after blooming), you can resume mowing the area again.

11. Mix Bulbs with Perennials

You can also plant perennials on top of the bulbs, to disguise the bulb foliage as it dies back. Spring-blooming groundcovers such as Phlox, Veronica and Thyme work particularly well, as they will bloom in tandem with the bulbs. We recommend Veronica and Daffodils, Tulips and Thyme and Phlox with Hyacinth and Allium.