Knowing when to plant bulbs in fall is important to ensure successful spring flowering. These tips show you when, where, and how to get started with fall-planted bulbs.
Looking for bulb options? See 20 Flowering Bulbs to Plant in Fall.
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With your favorite fall-planted flowering bulbs ready to go, it’s time to prepare for planting.
For fall-planted bulbs, we need to know:
- When to plant (soil temperature and timing in relation to first frosts)
- Where to plant (preferred soil, water, and light conditions)
- How to plant (soil depth)
While fall-planted bulbs do give us a jump-start on spring blooms, the reason we plant bulbs like tulips, daffodils, hyacinth, crocus, and snowdrops in autumn is because they need a dormancy period prior to flowering. Without this winter rest time, they may not have what it takes to grow and bloom.
For many of us, bulb planting is a simple task. Pick a fine fall day, dig a hole deep enough to bury the bulbs, toss them in, cover them with soil and call it a day. And that often works just fine. It may also be the only way it gets done if you’re short on time or have a lot of bulbs to plant.
Where I am in Ontario, Canada, optimum planting time is from mid-September through October, when various natural signs and signals like leaf drop tell us it’s time, prior to first frosts in late October or November.
Practically speaking, you must get it done before the ground freezes when digging is impossible.
For your best chances of success—with lots of beautiful flowers from late winter onwards—use these tips.
1Start With Healthy Bulbs
Have a look at the bulbs before you buy or plant them.
Are they firm and dry? Healthy looking? Free of mushy spots, mold, or bruises? Good! If not, choose others.
If you have received unhealthy bulbs by mail order, contact the company and exchange or return them.
Some people ask about the papery skins that peel and come off. That’s fine! It’s a natural protective layer but they will come off over time. Just don’t force them.
2Plant at the Right Time
Best Soil Temperature for Bulb Planting
In general, the optimum time to plant bulbs in fall is when the soil temperature is 60°F/16°C (or cooler) but before first frost.
If you want to check soil temperatures, use a meat thermometer, and check the soil at planting depth. Measure at different hours of the day over several days to get the average. There is more on checking soil temperatures here.
If you don’t want to take your soil’s temperature, find out your average first frost date (you can look it up here) and be sure to get them planted at least two weeks earlier.
Many bulbs need 16 to 18 weeks of cold temperatures to produce blooms the following spring or summer. Missing this dormancy period is one of several reasons our bulbs may not bloom.
In addition to planting in the ground, you can also grow bulbs in containers. See Tip 4 for more.
3Plant in the Right Place
Planting location in your garden and how deeply you plant the bulbs both matter.
I mentioned gardeners casually burying bulbs in the ground and calling it a day, and that’s great if conditions happen to be right, but it won’t go so smoothly if your bulbs are planted too deeply, get limited sunlight, or find themselves soaking in a boggy area.
All bulbs need well-draining soil to prevent rot, but, beyond that, some like tulips do best with full sun while bulbs are fine with part sun.
To get it right, check your product labels for planting instructions.
Wrong location? Yes, You Can Transplant Flower Bulbs.
What if I don’t have a plant tag or label?
If you know what the bulb is (tulip or whatever), look it up. Otherwise, here are some tips.
In general, bulbs should be planted at twice the depth as the bulb is tall.
If your flower bulb is approximately 3-inches tall, you would dig 6-inches deep in the soil for planting.
You will find all sorts of advice on best planting depths—much of it contradictory—but this is my best guesstimate.
If your climate is colder (zone 5 or lower), you can also insulate everything with a few inches of mulch on top until things warm up in spring.
Bulb Fertilizer: I don’t buy it. Bulbs already have the energy to produce leaves and blooms. Instead of randomly adding bulb fertilizer that may not benefit your conditions, take a step back and manage the overall healthy of your soil for the well-being of all your plants.
4Know Thy Bottom from Thy Top
Each bulb has a top and bottom. On some, it is more obvious than others. The top is often somewhat pointy. The bottom is flatter and there may be fine roots already there.
When planting, the bottom sits on the soil and the top faces up.
If your bulbs are not making this obvious, don’t sweat it. They will still grow and bloom when planted upside-down: it just requires a little extra growth to get turned around.
TIP: Be sure to mark your planting locations with plant markers or rods so you don’t accidentally dig them up during spring planting.
And put the markers in before the bulbs so you don’t accidentally pierce them.
5Plant in Containers
I consider planting bulbs in containers an insurance policy of sorts. While I cannot completely stop wildlife from digging up bulbs in the ground, I can keep them from getting into containers.
If you do plan to use containers, there are a few extra steps needed.
- Have a winter storage space ready where you can keep the container accessible (for monthly checkups) and just above freezing.
- Choose a container wide and deep enough to accommodate the bulbs you have chosen (read your label) and make sure it has drainage holes.
- Use container potting mix.
- Water at planting time and cover with hardware cloth (fine wire mesh) to keep critters including mice out. I put a brick on top to secure it.
- Store in a garage or shed with insulation around the pot to prevent freezing. I use old blankets, old coats, bubble wrap, foam, or whatever I have on hand.
- Set a reminder on your phone to check on the pots monthly.
In spring, the containers are re-introduced to light, warmer temperatures, and watered so the plants can grow and bloom. These tips on overwintering potted trees follow the same steps.
Generally speaking (again), when temperatures hover around 60°F (15°C), it’s time to wake up the bulb containers from storage.
You can also force bulbs indoors using these instructions.
Bulb Layering Tip for Extra Beauty
For a single growing season, consider layering bulbs in a container.
- Plant from largest to smallest working from the bottom up.
- This will provide continuous blooms and a lovely array of flowers.
- After the foliage has died off, dig up, dry, and store the bulbs for future planting.
Leftover bulbs should be dry (but not dried out) and can be stored in a cool (above freezing), dark location until next planting time.
And that’s it.
As warmth and light return in spring, the bulbs will do their thing. Bloom times will depend on what you planted.
Whether on not bulbs grow perennially will also depend on what you planted and your growing conditions. Many types of flowering bulbs provide several years of blooms or more. Some, like alliums, may need replacing every couple years.
~Melissa the Empress of Dirt ♛