Forcing Bulbs

Daffodils for forcing

Each fall I pot up daffodils, tulips, crocus and other bulbs for indoor blooming. Now is the time to do it. It takes a long time for bulbs to establish roots and get ready to bloom, come spring, so the sooner you do so the better. Most bulbs need three to four months before they are ready.


Most bulb packages will specify early, mid-season or late blooming times. When selecting bulbs for forcing, choose early-blooming or mid-season varieties. Species tulips like Fosteriana and Kaufmanniana are both early. The Darwin hybrids are early- to mid-season varieties that force well. Triumph tulips are also good.


Forced Tete-a-tete daffodils

Of the early daffodils my favorite is Tete-a-Tete which produces small gold flowers, 2 or 3 blossoms per bulb. These are readily available in grocery stores in early spring and I buy them already blooming in small pots for under $5. One of my favorite things to do with them is to put a pot in a rubber boot in the mudroom, their blossoms poking out of the boot. It always evokes a reaction from visitors.


So how do you force bulbs? Plant them in ordinary potting soil in pots and keep them in a cool spot that stays slightly above freezing, and never more than 50 degrees. I have a cold, above-ground basement that is perfect for that. But you can keep them in the garage or perhaps the bulkhead.


No harm is done if temperatures drop below freezing for part of the time they are getting ready, but no growth occurs when they are frozen, so keeping them above freezing is better.


Bulbs have everything they need to bloom already packaged inside. You don’t need to fertilize the bulbs when you plant. Each fall I clean out all the pots that had annual plants on the deck and save the potting mix in a big contractor bag. I use that potting material to fill other pots for forcing bulbs.


Mice can be an issue if planting tulips or crocus, though daffodils and alliums are of no interest to them. I cut squares of plywood large enough to cover any pots I use for tulips. I put a brick on top of the plywood to keep mice out – they can squeeze through incredibly small spaces.


Most gardening books warn against watering the soil mix in which you have planted bulbs. They say bulbs will rot if too wet. That may be true, but I’ve found that in winter my problem has been more with the soil drying out too much. Humidity is very low in winter, and the potting mix, which is peat-based, loses moisture quickly by evaporation. I check the soil once a month and water if the soil feels dry. One year I let the mix dry out to much and did not get many blossoms. Always start with lightly moist soil mix.


Forced daffodils

Clay pots may look good to you, but they can allow moisture to evaporate quickly from the sides of the pot. Plastic, fiber glass or porcelain containers are better for bulbs because they hold the moisture of the potting mix, minimizing water loss.


So how close can you plant your bulbs? Basically as close as you want. I have some nice Italian pots that I use each year for forcing. They are rectangular, roughly 14 inches long, seven inches wide and six inches deep. I put 8 to 10 bulbs in each one. In a 10-inch round pot I put 10 daffodils. An inch or two between bulbs is fine.


Most pots do not allow the same planting depth you would have outside. Instead of 6 inches of soil covering a tulip or a daffodil, two or three inches is fine. I put a thick layer of soil in the bottom of the pot, then arrange the bulbs on it. I push down on each bulb to set if firmly in place, and then cover with soil mix. A light watering is good after patting the top of the soil to firm it up a bit.


If you do have a deep pot – 10 inches or so – you can plant 2 layers of bulbs. Plant daffodils near the bottom of the pot, add soil mix, and then add some small bulbs like crocus or snowdrops near the soil surface. Just leave a little more space between the small bulbs than you might otherwise so that the daffodils can grow up between them.


How do you know when your bulbs are ready to bring into the warmth of the house? Make a tag for each pot that tells you what is planted, and when it was planted. Eight to twelve weeks is fine for daffodils, and 16 weeks for tulips. But look at the pots. If buds are up and craving light, bring them up a little early if you wish. But never bring tulips up before the end of February or they won’t bloom.


Winter is often a hard time for gardeners. We crave working in the soil and seeing things grow. Forcing bulbs indoors is one way we can satisfy our need to have flowers – even with snow on the ground.


You may reach Henry at PO Box 364, Cornish Flat, NH 03746. Please include a SASE if you want a written reply. Better yet, e-mail him at You may read his blog posts at


Forcing Bulbs

     I love to ski and snowshoe. I don’t mind shoveling snow and lugging in firewood for the woodstove the chugs along day and night now. But there are limits to my patience, and by March I’ll ready for green growing things and some fresh flowers. So I start lots of veggies and flowers by seed, starting in March and April. But I also force bulbs to bloom indoors in March. Now is the time to do so.


          Most bulbs are described on their packages as early, mid-season or late. Go to your local garden center and ask for bulbs that are early bloomers because they are the best for forcing. Buy daffodils, some tulips and maybe some small bulbs like crocus or snowdrops. You can plant these bulbs in large pots or even in your window box that is, by now, cleaned out and stored in the garage or barn.


           You will also need some potting soil and compost. I make a mix that is half compost, half potting soil for forcing bulbs. I don’t use garden soil because it can be heavy and often stays wet. Bulbs can rot if they are left in wet soil for too long.


daffodils being planted for forcing

daffodils being planted for forcing

I recently planted 25 daffodils in a window box that is about 30 inches long, 6 inches wide and deep. It was a mix of different kinds of daffodils. I prefer to get all of one kind so that they all bloom at once, but the mixed bag was what was available (and on sale).


          I filled the window box a little more than half full with my mixture of compost and potting soil and placed the bulbs, pointy end up, in the soil. Once I had them all in place I pushed them down more and filled up the box with more potting soil-compost mixture. Bulbs for forcing can be planted shoulder to shoulder, or nearly so.



                    In order to prepare bulbs for early blooming indoors, you will need a place to store them that is cold, but not as cold as the outdoors. Despite global warming, I still see minus 20 every winter, even if for only a few days. Bulbs planted in the ground have some protection against the cold, but if you were to plant bulbs in pots and leave them outside, the extreme temperatures would kill most. Bulbs left in a cool basement or garage will do just fine. Inside the bulkhead to your cellar might be the right temperature, too.


Ideally temperatures for bulbs used for forcing will be between 25 and 50 degrees, though colder temperatures should not be a problem (my basement often goes below freezing). Left in a warm location, the bulbs will grow green tops – but not blossoms.


You need to be aware that rodents like eating bulbs (indoors or out) – especially tulips. My basement has, most years, harbored mice and even sometimes red squirrels. In fact, I have learned the hard way that indoor rodents can – and will – dig up and eat tulips. So now I keep my pots of tulips covered with hardware cloth (a fine-mesh metal screening available at hardware stores). But wear gloves if you cut hardware cloth to size – the edges are as sharp as razor wire. Daffodils, on the other hand are not of interest to rodents as they are mildly poisonous.


      You can double your production of blooms by planting two layers of bulbs in a container. Plant big bulbs deep in the pots, add soil, and then plant a layer of crocus or other small bulbs above them. To avoid planting the little guys right over the big boys, you can mark the location of the deeper bulbs with straw from a broom. That way they won’t get pushed over as the daffodils come up. Or you can just take your chances.


Don’t wait until mid-December to start your bulbs, get on this project now. Daffodils take about 12 weeks of dormancy before they should be brought into the warmth of the house, and tulips do better with 4 full months. Planted now, they would be ready in mid-March. Little things like crocus can be forced in 8 to 10 weeks.

Forced flowers

Forced flowers

It is important to check on the bulbs you are forcing at least once a month, particularly if you have put wire rodent-proofing over the containers. I’ve had shoots get damaged by trying to grow through the hardware cloth. If the bulbs are sending up shoots, remove the wire mesh. I also don’t want the soil mix to get bone dry, so I check it and water a little if it is too dry. The bulbs will grow roots when first planted, and then go dormant if kept in a dark, cold location.


When it is time to bring up your potted bulbs into a warm place, let them wake up gently. My mudroom is good for starting them: there is some sunshine but it is cool. Then, once the shoots are up and green, I place the containers on my sunniest window sills – either east or west facing.


I was a Peace Corps volunteer in Cameroon, West Africa many years ago. There I could have flowers blooming outside every day of the year. It spoiled me, perhaps, because I still want flowers every day. Forcing bulbs is one way to have lots of blossoms when there is still snow on the ground.


Henry Homeyer is the author of 4 gardening books. His Web site is You may also reach him by e-mail at


Preparing Bulbs for Forcing


            Winters here can be long and cold.  Sometimes they are burdensome for a guy like me who loves being outside playing in the garden – planting and picking flowers, or harvesting lettuce and berries. But like the squirrels, I’m planning ahead and burying some little round things for future enjoyment. Nuts? No, I’m not. I am planting bulbs in pots now so they will bloom indoors in February and March.


            Each fall in early November I plant tulips and daffodils and sometimes crocus in pots, planters, and in a window box that I take down and bring into the basement where it’s cool and dark. Almost any spring bulb can be planted for forcing, and now is the time to do it.


Daffodils for forcing

Daffodils for forcing

One nice thing about forcing bulbs is that the deer cannot get them. Tulips are like magnets for deer and rodents in many neighborhoods, though my fierce and determined Corgi, Daphne, does a pretty good job of deterring them for me. But tulips growing inside are unlikely to be bothered by anything. That said, one year rodents did get in my basement and dug up tulips that were in pots, so I sometimes cover containers of tulips with wire screening I get at the hardware store called hardware cloth.


My window box is one I built over 10 years ago out of cedar and it is still holding up nicely. (A nice winter project might be to make one yourself. Directions are in my first book, Notes from the Garden, which is now out of print but available at many libraries.) The box is 36 inches long and 7inches deep and 9 inches from front to back.


            Outdoors I plant tulips and daffodils so that their tips are six inches below soil surface, and 2 to 3 inches apart. But in my window box I plant them closer together to cram as many bulbs as possible in the space given. I plant them in 2 inches of soil mix so that they have plenty of space for their roots, but this means their tips are just below the surface of the planting medium after I fill up the box.


            I start the process by dumping out all the plants and soil from my window box. I take a stiff scrub brush (the one I use for cleaning out garbage cans) and clean the window box as often roots and dirt are sticking to it. I have drilled holes in the bottom of the box for drainage and I check to see that they’re not clogged.


            Garden soil is great for growing bulbs outdoors but is not ideal in a container. In a pot it tends to get compacted by watering. So I make a mix that is 50% compost and 50% potting mix that I buy. That mix is very light and fluffy because it contains peat moss and perlite. Perlite is an expanded mineral – sort of a rock popcorn. It’s the white stuff that looks like Styrofoam in potting mixes.



Forced Daffodils

Forced Daffodils

I planted 25 large daffodils in my window box, which was a bit of a squeeze, but will be dramatic when they bloom. Some years I plant 2 or 3 varieties of  daffodils in it to stagger the bloom time, but this year I went for the “Big Bang” look – all blooming at once. I will bring the box out of the cold basement in early March.


            After planting I water the mix lightly if it is dry. Bulbs won’t do well if sitting in soggy planting mix, but they also are living beings that are growing roots and that need some moisture. If the soil mix dries out too much, I sometimes do a light watering half way through their winter rest.


            When selecting bulbs for forcing, “early-season” varieties are best. Some varieties will be listed as “good for forcing” and those are ideal. Daffodils I give a minimum of 90 days of rest before bringing them into a warm room to start the process of above-ground growth. Tulips I recommend 120 days – 4 months from now is mid-March. If you bring them up without proper rest, you will get foliage but no blossoms. Crocus are ready in 10 weeks or so, but can be planted in the same container as daffodils – as a second layer of bulbs above the daffodils. 


            Those 8-inch plastic pots that are used for perennials at the garden center make good pots for forcing, too. Half a dozen tulips in one will make a very nice display indoors while there is still snow on the ground. Plant several pots and bring one into the warmth every week for a continuous display.


            Oh yes, temperature is important, too. The ideal temperature for forcing bulbs is 40-45 degrees. Anything over 50 is too warm, and below freezing is too cold. You might have a place in your garage or on the steps of the bulkhead, or even in an unheated mudroom. It is best to keep the pots in the dark, but you can create that by placing a plank over the top, I suppose.         


            So go get some bulbs and pot them up for a late winter delight. It’s easy, it’s not costly, and you can plant those bulbs in your garden after they have done their work – cheering you up.


Henry Homeyer is the author of 4 gardening books and a fantasy-adventure for children, Wobar and the Quest for the Magic Calumet. His Web sites are and


Forcing Bulbs for Spring

Posted on Wednesday, October 31, 2012 · Leave a Comment 


          Winters can be hard on many gardeners: short dark days, icy roads and little to do in the garden. Yes, I like to snow shoe and cross country ski, but it doesn’t replace gardening. I water my houseplants (and occasionally talk to them), but they are weak substitutes for the real thing. By the time mud season comes in March, I want blooming flowers to brighten my life.


I get early blossoms in two ways: First, I have early bulb plants outdoors, including hundreds of snowdrops that bloom in March. And second, I force bulbs to bloom early indoors. Now is the time to plant bulbs so that they will bloom when we need them the most – a month or two before they bloom outdoors. 


          In order to prepare bulbs for early blooming indoors, you will need a place to store them that is cold, but not as cold as the outdoors. Despite global warming, I still see minus 20 every winter, even if for only a few days. Bulbs planted in the ground have some protection against the cold, but if you were to plant bulbs in pots and leave them outside, the extreme temperatures would kill most. Bulbs left in a cool basement or garage will do just fine.


Ideally temperatures for bulbs used for forcing will be between 33 and 50, though a few days of below freezing temperatures is not be a problem (my basement often goes a below freezing). Left in a warm location, the bulbs will grow green tops – but not blossoms.


Bulbs can be planted for forcing in pots or window boxes. Good drainage is important to avoid rotting the bulbs, so don’t plant them in ordinary garden soil. I think an ideal mix is one that has half compost and half potting mix. I want the mix to be lightly moist at planting time, but not soggy. Once a month I check the pots to make sure the soil is not bone dry; if it is, I water lightly.


Forcing Bulbs

When planting daffodils or tulips outdoors, I plant them 6-8 inches deep but that is not necessary when planting bulbs in pots. Depending on the type of container I use, the pointy tips of my bulbs may be just an inch or two below the soil surface. And I plant them shoulder-to-shoulder, crowding in as many bulbs as possible in the container. After they finish blooming in the spring I will plant the bulbs outside, but for now they have everything they need to bloom inside the house.


Timing is key to success with forced bulbs. Little bulbs like crocus need just 8-10 weeks of dormancy, but daffodils need 12 weeks, and tulips do better with more, up to 16 weeks. Choose bulbs that are marked “Good for Forcing” or that are listed as “early” rather than mid-season or late. If you are selecting bulbs now, make sure that they are still firm, not papery and dried out. And if you see them with long green sprouts, pass them by.


Beware of mice. If you have mice, they will eat your tulips unless you exclude them somehow – with wire mesh screening, for example. Daffodils are lightly poisonous, so mice don’t eat them.


You can maximize blooming by planting two layers of bulbs. I often use those 8-inch pots that perennials come in for forcing. They are not elegant, but can be dressed up with wrapping paper or baskets when displayed on the table. I put in an inch of gravel, an inch or two of soil mix, then daffodils or tulips. I cover them with soil, and then add a second layer of bulbs. The small bulbs like crocus work well for a second layer. Leave a little space at the top of the pot for watering.


Forcing Bulbs

When planting two layers of bulbs I used to worry about the big bulbs coming up and pushing the little ones aside like playground bullies. So I carefully placed the little ones above the spaces between daffodils. I even used broom straws to show me where to plant. But one year I just put them in without worrying about crowding and every bulb did fine. Plants know more than we give them credit for, I think.


When you take your plants out of their cold resting spot, most will begin to grow almost immediately. I generally start mine off in a cool location in the house, and once they have fully woken up I put them on a sunny, warm windowsill. A trick for prolonging their blooms (which also works with cut flowers from the florist) is to move the flowers into a cold mudroom or entryway at night. Cool temperatures prolong the life of your flowers.


So go to your local feed-and-grain store, garden center or food coop; get some bulbs and prepare them for forcing. Come March you’ll be ready for spring, and will have some flowers ready to perform their annual dance before their cousins outside do.


Henry Homeyer has a new children’s chapter book that just came out: Wobar and the Quest for the Magic Calumet. Read about it at


Filed under Article · Tagged with , ,