Summer is still in full swing, and yet it’s already time to begin thinking about next year’s spring garden. That’s because some of your favorite spring blooms need to be planted as bulbs in early fall when the ground is cool. For those of us in the coldest US climates, that means late August or early September. Getting the timing right for bulb planting can be tricky business, so we’re breaking it all down here. Read on to learn when to plant your bulbs and how to set them up for a successful spring bloom.
When to plant spring bulbs
Like most flowers, there’s an optimal time to plant spring bulbs. And yet, it’s not as straightforward as with other garden varieties. Here’s a quick rule of thumb for when to plant your bulbs, based on your USDA growing zone:
- USDA Zones 1 to 4: Plant in late August or early September when the ground begins to cool.
- USDA Zones 5 to 7: Plant in September through November, depending on the year. This is where the calendar isn’t really to be trusted. Instead, wait until evening temperatures average around 40° to 50°F.
- USDA Zones 8 and higher: The ground in these climates likely won’t get cool enough for your bulbs to chill until quite late in the year. Instead, you’ll want to purchase pre-chilled bulbs or keep your bulbs in the refrigerator for 6 to 10 weeks before planting. Be careful not to store them with fruit or vegetables that emit ethylene (like apples), as that can be fatal for the plant inside the bulb.
What to look for when shopping for bulbs
When selecting bulbs, look for those that are large, plump and firm. Avoid any that are spongy or softening. You’ll also want to look closely at the bulbs to check for signs of disease, mold or damage. When it comes to price, it really can be worth it to splurge on the more expensive bulbs. Likely those are ones that will have the most brilliant blooms. If you need some guidance on which varieties to choose, check out our post on our favorite spring flowers, or our guide on the different types of bulbs that you’ll likely come across in your garden center.
Preparing for bulb planting
Bulbs can be a little picky about where they’re planted, as they don’t like to be too shallow or too deep. A good rule of thumb is to plant the bulb 2 to 3 times as deep as the bulb is tall. An auger drill bit or our bulb planter will be your best friend in the garden if you plan to plant more than a few bulbs, as they’ll give you perfectly deep and wide holes every time. You’ll want to make sure your bulbs are planted in an area with great drainage. Otherwise, they’ll rot as they lie dormant for weeks underground. If your soil needs a little help in this area, you can loosen it up by mixing in some organic material and doing some gentle tilling by hand. Companion plants are a good way to keep your planting area healthy while the bulbs are dormant. Look for perennials like thyme, bleeding heart, daylilies, and sedum.
