(Almost) Never Too Late to Plant Bulbs

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Ill.: Claire Tourigny & clipartstation.com

Normally spring flowering bulbs (tulips, daffodils, hyacinths, crocus, etc.) are planted from September through November in the Northern Hemisphere. In my climate (USDA zone 3), however, the soil often freezes before the end of October and I’ve occasionally had to plant bulbs in the frozen ground. Fortunately, soil freezes on the top first before frost reaches any depth, forming essentially a thin crust of frozen soil over the still friable garden soil below. So, I’ve found it fairly easy to simply break the frozen crust of soil like a sheet of thin ice and plant my bulbs.

However, if you know in advance that you won’t be able to plant bulbs until a very late date, you can put a thick layer of compost or leaf litter on the planting site. Both give off heat and will prevent the ground from freezing until you are ready to dig, at least for a while. Even so, you really should plant your bulbs by mid-December at the latest!

No-Dig Planting in Frozen Soil

I was once caught off guard by a late delivery of narcissus bulbs. It was only late November, but that year winter had come early and the ground was knee-deep in snow. What to do? I figured the bulbs were lost!

Then we had a January thaw, most unusual where I live. The snow didn’t all melt, but there had been several days of mild weather and rain and I was hopeful the ground had thawed out under the snow. So, I went out and dug a hole in the snow. Bad news: the soil was frozen solid. What to do? 

I figured I’d take a chance and did the following.

I went back inside and brought out a bag of potting mix. I dumped a layer of mix about 2 inches (5 cm) thick to the bottom of the hole so the bulbs would have something unfrozen to root into, then set the bulbs on that layer. I then covered them with about 6 inches (15 cm) of mix and shoveled more snow back on as insulation.

We’d see what we’d see.

Narcissus growing in a mound
The narcissus still bloom where I planted them nearly 30 years ago. Ill.: Claire Tourigny

Well, when the snow melted next April, up come the narcissus flowers from a little mound in the garden. They were in perfect condition! And last time I checked (I no longer live there, but the garden is easily visible from the street), they bloom there still, some 30 years later. 

Article adapted from one published on November 3, 2014.

What to Do with Forgotten Bulbs

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What can you do with the fall bulbs you forgot to plant?

So, you bought a few packs of spring-flowering bulbs (tulips, daffodils, crocuses, hyacinths, etc.) last fall, intending to plant them right away. Except it’s now winter and it’s apparently too late to plant them, what with the ground is frozen or covered with snow. It looks like you missed the boat. So, can you keep bulbs over the winter and plant them in the garden next spring?

In general, that’s not a good idea. Most of these bulbs will not bloom unless they undergo a long, cold winter. But there are several other options:

Extra-Late Planting

The most logical thing to do with fall bulbs is still to plant them outdoors, even though it’s later than normal.

If the soil is not yet frozen (that will depend on your local climate), there is no problem in planting tulip bulbs, narcissus, crocus, etc. as late as December or even January.

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So what if the ground is covered with snow? Just brush the snow aside and dig a hole.

If there is snow on the ground, sometimes you can just brush it away before planting and still dig.

If the ground is frozen, but only on the surface, it’s easy enough to break through the frozen crust thus formed. Then just plant as you usually would, digging a hole three times deeper than the bulb is high (for tulips, a depth of 1 foot/30 cm is preferable) in rich, well-drained soil somewhere that receives spring sun. There is even an advantage to planting a bit late: often the surface soil refreezes quickly after planting, keeping the bulbs safe from squirrels.

No-Dig Planting

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With no-dig planting, just dump packaged soil over the bulbs and let Mother Nature do the rest!

If crunching through a crust of frozen soil is not your idea of easy gardening, here’s an equally effective, but faster method.

First remove the snow, if there is any, then set the bulbs on the ground. Now, here’s the neat part: you don’t really have to dig a hole at all. Just cover them with a bag or two of garden soil or potting soil. Again, strive for a depth three times the height of the bulb. The warmth of the fresh soil will thaw the ground below, allowing the bulbs to root well… and they’ll be buried deeply enough that they won’t freeze until they’ve rooted in, which is what you want.

I’ve used the “no-dig planting” method during a January thaw and had great success.

This is the ideal method for planting bulbs where there is root competition too, such as in a wooded spot, even when the soil isn’t frozen.

Too Late, the Soil is Frozen Solid

The two previous methods only succeed when the soil is not frozen or only frozen on the surface. If the ground is frozen so deeply that a shovel can’t penetrate it, then it really is too late to plant your bulbs outside this season. But there are still other possibilities.

Forcing to the Rescue

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Forcing bulbs is easy: just pot up your bulbs and keep them moist and cool.

You can also force bulbs indoors for spring bloom in pots and in fact, this is the most logical solution to apply when the ground is thoroughly frozen.

Just pot them up and water well. Seal the pot inside a plastic bag (to prevent evaporation, as you’ll want the roots to remain moist at all times) and place it in a refrigerator, a heated garage or a cold room. It takes about 13 to 14 weeks (three and a half months) of cold for the bulbs to get ready to bloom (a bit less for hyacinths), then in late March or early April, set the potted bulbs on a bright windowsill… and fill your home with blooms!

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Forced bulbs just starting to bloom on a windowsill.

You will find more information about forcing in the article Forcing Bulbs without Twisting Arms.

Pre-chilling

It is also possible to store the bulbs dry in a cold spot over the winter, thus giving them the cold period they require for blooming… before you plant them. This technique is called “pre-chilling” and is commonly used to make tulips, hyacinths, narcissus, crocus, etc. flower in regions where they normally wouldn’t bloom because the winter isn’t cold enough for them (spring bulbs are cold climate plants: without a cold winter, they won’t flower). If you see tulips or hyacinths blooming at Disneyworld, on the French Riviera or in Australia, their bulbs were probably pre-chilled.

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Store  your bulbs cool but well-aerated.

For pre-chilling, store your bulbs bare (i.e. unplanted) in the refrigerator, a barely heated garage or in a cold room over the winter. The temperature should remain between 34˚ and 40˚F (1˚ and 5˚C) at all times. They can be stored loose in an open box or container or placed in a mesh bag, a paper bag or a nylon stocking, but never inside a plastic bag (under plastic, there is too much risk of condensation and during pre-chilling the bulbs must remain dry).

Now, where spring comes around, plant the pre-chilled bulbs outdoors as soon as possible, while the soil is still cool too cold. There is then a very good chance that not only will they bloom beautifully this first spring, but that’ll they adapt and come back to flower again and again for many springs to come… that is, if you live in a cool to cold winter area. (In warm-winter climates, such bulbs will not come back and are best treated as annuals.)


So, to resume the situation: the very best way to ensure that spring-flowering bulbs bloom beautifully not only the following spring but also perennialize well still remains planting them outdoors in the autumn according to the traditional method. But at least you now know what to do if you miss that opportunity!20161212a