At this point in October, bulb planting is probably well underway in many parts of country — some areas are probably expecting their first frost soon. But because I live in the South, and because this has been a very warm fall so far, I’ve barely thought about bulbs yet. We can’t start planting here till it cools off a bit anyway, and it’s often hard to know when exactly is the right time to get bulbs in the ground.
I recently got a packet of information from the Netherlands Flower Bulb Information Center that gives some general rules about bulb planting, and I thought it was useful enough to share here:
Is it better to plant bulbs earlier or later in the fall? As a general rule, earlier is better – as long as the soil temperature has cooled sufficiently. One way to gauge “the right time” is to wait until autumn night-time temperatures drop below 50° F (10° C) for two consecutive weeks. Once planted, bulbs need to establish strong root systems before the frosts of winter set in and the bulbs enter a new cycle in preparation for spring blooming. Planting six to eight weeks prior to hard frost is ideal, but bulbs manage to thrive with far less lead-time. Remember to plant bulbs in areas that drain well and water newly planted bulbs to help get those roots growing!
When is the optimal time to plant tulips, daffodils and most other bulbs in fall? In most areas, the “window” of time for planting bulbs in fall is fairly wide. Here is a practical way to plan:
- Time to start planting bulbs: once night-time temperatures in your area drop into the low 50s ° or 40s° F (4-10° C) for two weeks.
- Time to finish up: once hard frosts approach. Generally bulbs root best in the period six weeks or more prior to the ground freezing.
So, how do you know when the first frost will be where you live? I find the following sites to be useful in this regard — the dates estimated for your zip code are based on many years of compiled data.
The bottom line? Fall-planted bulbs begin to grow roots as soon as they are watered. Good root development gives them the strength to survive over winter.
Ideally, bulbs should be planted six weeks before the ground freezes, and knowing the date of the first hard frost in your area may help you calculate when the ground is likely to freeze.
Even if optimal planting time has passed, go ahead and plant bulbs. They won’t survive unplanted, and most late-planted bulbs will still grow and flower in spring.
Images courtesy of the Netherlands Flower Bulb Information Center.