The first time I ever tried rhubarb, it was a squishy mess inside a pie at a chain restaurant somewhere. I never wanted to eat it again.
That all changed the summer I moved to Alaska, when my parents convinced me to try the pie at a quaint Alaskan establishment, with the best view ever of mountains and the Matanuska Glacier.
Because of the breathtaking view plus gasp-worthy pie combo, we visit as often as we can.
Now an enthusiastic rhubarb convert, the sweet, tart tang of the red-green stalks haunted my winter dreams and made me ache for summer. Even though all my friends had pie plant patches in their gardens, I still didn’t.
That’s when I realized that I needed to grow rhubarb in containers during the winter.
My state may freeze for over half the year, but that doesn’t mean I can’t get a head start on growing my favorite pie filling in the world.
And so can you! In this article, I’ll show you exactly how.
Here’s what I’ll cover.
Why Grow in a Container?
A member of the Polygonaceae family, produces red or reddish-green stalks from springtime to early or mid summer, depending on the variety.
While the leaves are inedible and even toxic if consumed in large amounts, the stalks are deliciously edible.
Cooked down with buckets of sugar, they shine in pie. That’s reason enough for me to want to grow a whole field of pie plant!
Growing rhubarb in containers is an easy way to have your own fresh harvest of stalks even if you haven’t got much space in your garden.
Containers also help keep this plant in check, as once it’s established in your yard, rhubarb tends to take over, spreading so tall and wide – up to four feet both ways – that it can overshadow other crops growing in the area.
In southern climes – USDA Hardiness Zones 9 and above – rhubarb plants perish when temperatures rise in the summer, which is why it’s often grown as an annual in those locations.
If it isn’t too hot out – meaning temperatures stay around or below 80°F – rhubarb thrives, and then naturally goes into dormancy during the late fall and into the winter months.
Rhubarb then needs to chill out at 40°F or below for at least six weeks.
For those in Zones 7 or 8, the weather doesn’t always comply with this requirement.
Bringing your plant into a cool place like a basement or barn during these months will help it stay happy during its winter rest and allow it to put all its energy into producing tasty new stalks come spring.
This is easy to do if you grow the plant in a container.
Choosing the Right Container
Are you planning to plant crowns, divisions, or bare roots in pots outdoors? Then you’ll need a container that’s at least 20 inches tall and wide.
It’s up to you whether you want to use a light plastic one, a more robust terra cotta variety, or something pretty and ornamental. Read more about what material is best for containers, pots, and planters.
For starting seeds that you’ll later transplant to a larger outdoor container, select a pot that’s at least 8 inches wide and 7 inches deep.
This gives your plant plenty of room to grow and establish before transplanting – without taking up scads of space in your house.
Alternatively, you can start seeds in trays and transplant later.
Make sure you select a pot that has a draining dish, drainage holes that don’t leak, or a self-watering insert.
You can also fill a regular pot with a layer of gravel to promote drainage away from the root system.
Preparing Your Container
Fill your 20 inch by 20 inch container with either:
- Potting soil mixed with a little balanced 10-10-10 (NPK) vegetable fertilizer
- Garden soil amended with well rotted manure or compost (about half and half)
Use a good quality, organically rich potting soil that is well-draining. Rhubarb enjoys soil with a pH of between 5.0 and 7.0 – lightly acidic to neutral.
If you’re using garden soil, you may need to amend with compost or well-rotted manure. You can conduct a soil test if you are unsure.
How to Grow
You can propagate rhubarb in four ways: from a crown (a one-year-old plant), a division, a dormant bare root ball, or from seed.
We’ll discuss each method as it pertains to container growing so that you can make the best selection for your garden.
Planting a Crown
A rhubarb crown is a good way to start if you want stalks to harvest in the first season after you’ve planted it.
Make a four-inch-deep, six-inch-wide hole in the soil. Carefully remove your crown from its planter.
You may need to gently untangle the tendrils of the rhizome if the root ball seems very compacted.
Next, set the root ball in the hole, and backfill with soil. Don’t cover any part of the existing stalks or leaves with soil. All you need to do is make sure the root ball is covered.
Give the plant a thorough soaking and set the container in a location that gets at least six hours of sun, preferably more. Keep the soil moist, but not soggy.
For fall planted crowns, reduce watering over the winter months, and begin again when you see the first signs of life in springtime. Then keep the soil evenly moist but not waterlogged.
If you have planted your crowns in the spring, get ready to watch them grow. As I mentioned above, don’t overwater, but don’t let them dry out, either.
While you may be tempted to snip stalks off immediately, don’t!
Wait until stalks are 10-12 inches tall, and in the first season, harvest lightly, taking only 1/8 to 1/4 of the plant’s total stalks.
This will allow it to establish the strong root system it needs to produce truly delicious stalks a year after planting.
Planting a Division
If a friend is kind enough to give you a division from her rhubarb plant, rejoice!
Rhubarb plants are so sturdy that to divide them, you have to dig up the root and cut it in half (or into three pieces, depending on how large it is).
The plant is best divided in spring, when it’s starting to wake up from its winter dormancy, or in the fall, before it goes dormant.
See our full guide to dividing perennials for detailed instructions on how to do this.
Depending on the division time, the root balls (rhizomes) will be yellowish, chunky, tuberous things that may or may not have stalks and leaves attached.
Plant the division in a hole about eight to ten inches deep, leaf side up. Cover all but the top inch of the root ball with soil, and leave any remaining stalks, as well as the leaves, uncovered.
Water the division thoroughly and find the container a sunny spot on your porch or deck.
For fall-planted divisions, you’ll be able to harvest stalks the following spring. Spring-planted divisions will grow much quicker and be ready for harvest as soon as the stalks are 12-18 inches long.
If you’ve planted a rhizome divided in the fall, keep the soil moist until the plant goes fully dormant – in other words, until it dies all the way back.
For spring-planted divisions, keep them moist throughout the rest of the spring and summer and watch those mature stalks pop up. (Yes, you can harvest them!)
Planting a Dormant Bare Root Ball
A dormant bare root ball is essentially the same thing as a division, only it’s what the plant is called when you purchase it from a nursery, and it generally has just one pale, dormant bud.
Dig a hole eight to ten inches deep, depending on the size of your bare root.
Set the bare root inside, leaving the top inch, plus the bud, exposed. Whatever you do, to find the bud. It’s usually a very pale, one-inch-long bud near the top of the bare root.
The surest way to kill a bare root is to plant it root-side-up, bud-side-down.
If you don’t see a bud anywhere, contact the seller and explain the situation. They may be able to help you find the bud, or send a replacement.
Water your newly planted root ball thoroughly, find it a sunny, warm area, and keep the soil moist. If you plant in the fall, there’s no need to water the bare root once temperatures drop to 50°F and below.
The plant will stay comfortably dormant until springtime.
With springtime planting, leaves should emerge within two or three weeks, but don’t harvest during the first season.
Rhubarb planted from small bare roots need time to establish a strong and healthy root system – giving you a better second-season yield and a hearty third-season yield.
Since Alaska – along with other northern states from Washington to Maine – grows excellent rhubarb, I decided to start my own from seed in late January.
Rhubarb seeds are kind of funky looking, shrouded as they are in a papery casing.
To speed up germination, it’s recommended that you soak the seeds in tepid water for at least two hours before sowing, to loosen the casing around the seed.
Typically, you’ll start seeds indoors about three months before your area’s average last frost date.
I chose to start my seeds in neat little starter trays, which you can find on Amazon.There are six cells per tray, and ten of everything: ten trays, ten bases, ten “roofs” with 10 humidity adjustment knobs, and 10 labels.
To sow, make a one-inch deep hole, about the size of your fingertip, and drop one seed into each hole.
Lightly cover each seed with soil, give them a gentle but thorough watering.
Germination can take anywhere from seven days to two weeks.
After three weeks, I transplanted my baby seedlings into my eight-inch wide, seven-inch deep pots, prepared as mentioned above with potting soil and a little granular fertilizer.
Keep them in an area that gets at least 6 hours of sunlight per day (or use a grow light), and maintain even moisture, but don’t let them get waterlogged. As the rhubarb grows, you’ll notice more leaves developing from the stem.
In spring, when all risk of frost has passed and they are four to six inches tall, your plants will be ready for hardening off and moving outdoors, into a larger container.
To harden them off, place the pots in a partly sunny area protected from wind, rain, or excessive sunshine for two hours a day.
Over the space of a week, gradually increase this to eight hours, and then full time.
And voila! Your pie plant is on its way to becoming a one-year-old crown. Next summer, you’ll get to enjoy stalks from your very own seed-grown rhubarb.
Once established, rhubarb is easy to care for. It grows best in a sunny spot with evenly moist soil.
When growing it in containers remember that the soil can dry out more quickly than it would in the garden. Keep an eye out, especially during hot weather. If you haven’t had sufficient rain you may need to provide extra irrigation.
Mulching with shredded bark, woodchip or compost can help the soil to retain moisture, just be sure not to let the mulch touch the crown – keep it about an inch away from the stems.
In the late fall, after harvest, the plant will die back and go dormant for the winter. As mentioned above, it needs a winter chilling period of about six weeks with temperatures below 40°F.
Come spring, when you see the first signs of new growth, fertilize with a balanced 10-10-10 (NPK) granular fertilizer. Note that this may not be necessary if you are mulching with compost, as it will gradually rot down and provide extra nutrients to the soil.
Dividing Larger Plants
You won’t need to worry about this for about three or four years, but once your plants start to look too big for their container, it’s time for some division.
Wait until late fall or early spring to do this – when the plant is either about to go dormant for the winter, or when it’s just waking up in springtime.
With a trowel or hand rake, scrape at the outside of the root until you can reach down and pull it out with two hands. Take a flat spade in two hands and hit the root with it, slicing the tuberous yellow chunk straight down the middle, or use a garden knife.
Depending on how large the root is, you may want to slice it again crossways so that you have four chunks instead of two.
(Yes, your plant will survive this. It’s very hardy!)
Replant the chunks with the stalk (bud) sides up, douse them with water, and watch them pop up with new stalks in the spring.
- When planting crowns, bare roots, or divisions, plant directly into a 20-inch-by-20-inch container
- Keep your plants moist but not waterlogged until they die back in the fall
- Make sure your plants get at least six hours of sunlight
- Divide plants every three to four years for the best yield
Cultivars to Select
You can grow just about any cultivar in a container, but some varieties are smaller than others, making them better suited to growing in a smaller space.
Here are a couple of the more popular cultivars suitable for your container garden. See our guide to the best rhubarb cultivars for a full selection of what’s available.
This variety is perfect for container growing because it’s a bit smaller than other cultivars, growing just two feet wide and tall.
Plus, you can harvest it from spring all the way until late summer. And you can harvest ‘Glaskin’s Perpetual’ one year after planting from seed!
Sweet, tart, and a bit less bitter than some other varieties, the reddish-green stalks will be harvest-ready when they’re 12-14 inches long.
Find packs of 500 or 1,000 seeds from Outsidepride via Amazon.
Sweet and just tart enough to please, ‘Victoria’ is a cultivar that everyone has loved since it first popularized pie plant in the mid-1800s.
This one is well suited to container growing because it reaches three feet wide by three feet tall at maturity. While this sounds huge, it’s smaller than other cultivars!
‘Victoria’ is what I’ve been growing in containers, and it’s an excellent cultivar to start from seed. Find seed packets of 50 from Everwilde Farms via Amazon, like I did.
If you want to get a head start on the growing season you can also buy plants or bare roots available at Burpee.
Managing Pests and Disease
Rhubarb is impressively pest-resistant, and if you’re growing it containers, you won’t have as many (if any) weeds to worry about.
But keep an eye out for fungal leaf rot, which can happen if the leaves stay damp or damply hug other leaves for too long. An easy way to avoid this is to water at the base of the plant, avoiding the leaves entirely.
If you do find fungus, remove the infected leaf and stalk. You can still use the stalk, but removing the leaf will help keep the infection from spreading to the rest of the plant.
The number one pest to watch out for?
Rhubarb weevil, a yellowish, long-snouted, half-inch-long beetle that carves notches out of your beautiful stems and leaves.
Scrape the weevils off the plant if you spot them and kill them so that they don’t come back.
It’s important to catch them early, before they start laying eggs and multiplying at rates that are hard to keep up with.
To harvest your stalks, wait until the second season of their growth. That’s the hardest part, especially when your tastebuds crave pie!
Most varieties will be ready for harvest from late April through June.
When the stalks are 12-18 inches in length, harvest outer stalks by finding the base with your fingers and pulling firmly to break it off. The stalk should detach from the base, featuring a tapered end.
Cut the leaves off and whisk them off to your compost container.
Remember, they’re inedible and potentially even harmful due to high levels of oxalic acid, so you don’t want children or pets munching on them.
During your plant’s first harvest, take only about 1/4 of the total stalks. The following year, you can take all but 1/3.
By leaving behind a few stalks, you allow the plant to store energy for the winter dormancy and reawakening in the springtime.
If you live in Zones 7 or above, move your container to a cool, sheltered space: a basement, garage, or even outdoor freezer once it gets too hot (above 80°F).
It’s ideal if this space gets down to 40°F during the winter so your plant can go through the necessary chilling period. Your plant will be able to overwinter there, and come back in springtime.
If you are growing your plant as an annual, harvest every single stalk off your pie plant, watch it shrivel under the heat, and replant a new division or crown in fall or the following spring.
Those in Zones 3-6 can leave the containers outside to happily overwinter in the cold.
Recipes and Cooking Ideas
For use throughout the winter, cut stalks into one-inch pieces, lay on parchment paper, and freeze until firm. Then transfer to gallon freezer bags, making sure to mark the date you put them in the freezer. They’ll keep for up to a year.
Alternatively, you can make a delicious pie, like this one from our sister site, Foodal.
Try your hand at rhubarb jam or sauce, perfect for spreading into your ice cream. Maybe bake a crumble or spelt cake such as this one, also from Foodal.
You can even pair the pie plant stalks with things that aren’t pie. For a full list of pairable foods, check out this article on using rhubarb in the kitchen, from Foodal.
The options are endlessly tart and tasty.
Tart, Juicy Goodness Awaits You
By growing rhubarb in a container, you have more control over its growing conditions. As in, you can helicopter-parent your pie plant until it grows old enough for you to watch it fly away from the nest… and into your mouth.
I’ll be sitting here hovering over my six little plants for two years, just waiting until the gorgeous day when I can harvest them for the first time.
Until then, I’ll be making plenty of pie stops at Long Rifle Lodge, just off Mile 102 on the Glenn Highway in Alaska (in case you ever visit!).
What’s your favorite rhubarb treat? Let us know in the comments!
And don’t forget to check out our other guides to growing veggies in containers next:
- How to Grow Beets in Containers
- How to Grow Carrots in Containers
- Will Kale Grow in Containers? Tips for Growing Your Crop in Pots
About Laura Melchor
Laura Melchor grew up helping her mom in the garden in Montana, and as an adult she’s brought her cold-weather gardening skills with her to her home in Alaska. She’s especially proud of the flowerbeds she and her three-year-old son built with rocks dug up from their little Alaska homestead. As a freelance writer, she contributes to several websites and blogs across the web. Laura also writes novels and holds an MFA in writing from Vermont College of Fine Arts.
“How to Grow Rhubarb in Containers” was first posted here