Knowing when to plant bulbs in spring is the key to a beautiful summer garden. This guide will help you get the timing just right for a fantastic display of color.
Many gardeners think of bulbs as a fall-only task, but that’s not true. Spring is the perfect time to plant a whole range of summer and fall-blooming bulbs. If you get them in the ground at the correct moment, you’ll be rewarded with gorgeous flowers for months.
When To Plant Bulbs In Spring
This is the core question. The simple answer is: after the danger of a hard frost has passed and the soil has begun to warm. Planting too early in cold, wet soil can cause bulbs to rot. Planting too late gives them less time to establish before the summer heat.
For most regions, this means planting in mid to late spring. A good rule of thumb is to get them in the ground around the same time you’d plant tender annuals like tomatoes or peppers.
Understanding Soil Temperature
Soil temperature is a more reliable guide than the calendar. You want the soil to be consistently at least 55°F (13°C) at a depth of 6 inches. You can use a simple soil thermometer to check this.
- Below 50°F (10°C): Too cold. Wait.
- 55–65°F (13–18°C): Ideal for most summer bulbs.
- Above 70°F (21°C): Getting late for some types.
Regional Timing Guidelines
Your local climate is the biggest factor. Here’s a basic breakdown:
- Cold Climates (Zones 3-5): Plant from late May to early June. Wait until after your last average frost date.
- Temperate Climates (Zones 6-7): Aim for April through mid-May. The soil warms up reliably during this period.
- Warm Climates (Zones 8-10): You can plant as early as March or even late February. Some bulbs can be planted in winter here.
Always check a local gardening calendar or extension service for the best advice in your specific area.
Which Bulbs to Plant in Spring
Not all bulbs are planted in the fall. Focus on “tender” bulbs that can’t survive freezing winter ground. These are you’re spring-planting stars:
- Dahlias
- Gladiolus
- Canna Lilies
- Callas
- Begonias (tuberous)
- Caladiums (for foliage)
- Lilies (Asiatic, Oriental)
- Crocosmia
- Elephant Ears (Colocasia, Alocasia)
Step-by-Step Planting Guide
Once the timing is right, proper planting ensures success. Follow these steps.
1. Selecting and Preparing Bulbs
Choose firm, healthy bulbs without soft spots or mold. Larger bulbs usually produce stronger plants. Soak any dry-looking bulbs (like dahlia tubers) in lukewarm water for an hour or two before planting to rehydrate them.
2. Choosing the Perfect Spot
Most summer-blooming bulbs love sunshine. Pick a site that gets at least 6-8 hours of direct sun daily. Good drainage is absolutely critical. If water pools in an area, your bulbs will likely rot.
3. Preparing the Soil
Bulbs thrive in loose, fertile soil. Work the area to a depth of about 12 inches. Mix in several inches of compost or well-rotted manure. This improves drainage, provides nutrients, and makes it easier for roots to spread. A balanced, slow-release fertilizer can be added at this stage too.
4. The Planting Process
Depth and spacing are key. A general rule is to plant a bulb at a depth of 2 to 3 times its height.
- Dig a hole to the proper depth.
- Place the bulb with its “eyes” or pointed end facing up. If your unsure, plant it on its side; the plant will find its way up.
- Cover gently with soil and pat down to remove large air pockets.
- Water the area thoroughly after planting to settle the soil.
For a dramatic effect, plant bulbs in groups or clusters rather than single lines.
5. Post-Planting Care
Keep the soil consistently moist but not soggy as shoots emerge. A layer of mulch (like shredded bark) helps retain moisture and suppress weeds. As plants grow, you may need to stake tall varieties like gladiolus or dahlies.
Common Mistakes to Avoid
Even experienced gardeners can make these errors. Here’s what to watch for.
Planting Too Early
This is the most frequent error. Cold soil shocks tender bulbs and invites rot. Patience is a virtue in spring gardening.
Poor Drainage
Bulbs despise “wet feet.” If your soil is heavy clay, you must amend it with compost or consider raised beds. Soggy soil is a death sentence.
Incorrect Depth
Planting too shallow can lead to toppling plants; planting too deep may prevent them from blooming. Stick to the 2-3 times height guideline.
Forgetting to Water at Planting
That initial watering is crucial for triggering root growth. Don’t just rely on rain if the soil is dry.
FAQ: Spring Bulb Planting
Can I plant spring-blooming bulbs in the spring?
No. Tulips, daffodils, crocus, and hyacinths require a long period of cold dormancy. They must be planted in the fall to bloom the following spring. Trying to plant them in spring usually results in failure or no flowers for a year.
What if I missed the ideal planting window?
Don’t worry! You can still plant bulbs later in spring or even early summer. They may bloom a bit later or have a shorter season, but it’s better than not planting them at all. Container planting is a good option for late starters.
How often should I water after planting?
Water deeply once a week if there’s no significant rainfall. The goal is to keep the soil lightly moist. Once plants are established and growing well, they will be more tolerant, but consistent moisture leads to the best blooms.
Do I need to dig up bulbs every fall?
In colder climates (roughly zones 7 and below), tender bulbs like dahlias and cannas must be dug up after the first frost kills the foliage. Store them in a cool, dry place over winter. In warmer zones (8+), they can often be left in the ground with a thick mulch layer.
Why are my bulbs not flowering?
Several reasons are common: not enough sunlight, overcrowding, too much nitrogen fertilizer (which promotes leaves, not flowers), or the bulbs were planted to shallow and got damaged by temperature swings. Also, bulbs may need dividing if the clump has become to dense.
Can I plant bulbs in containers?
Absolutely. Containers are a fantastic option. Ensure the pot has excellent drainage holes. Use a high-quality potting mix, not garden soil. Watering will be more frequent, as containers dry out faster. You can create stunning, movable displays this way.
Getting the timing right for spring bulb planting sets the stage for a spectacular garden. By waiting for warm soil, choosing the right bulbs, and giving them a good home, you’ll enjoy a vibrant and colorful payoff all summer long. Remember, a little planning in spring leads to months of beauty.