How to Harvest Rhubarb

In this guide we teach you how to harvest Rhubarb plant. Rhubarb is an old-time plant with tangy, edible stalks. Though technically a vegetable, it’s most commonly used to make jams, jellies, pies, and other desserts. You’ll often see it paired with strawberries for a classic combination.

The rhubarb plant is a perennial that grows and produces best in cool weather. Once established in your garden, you’ll be able to get a good yield year after year.

Because it’s a perennial and grows from spring to fall, you might be wondering when and how to harvest your rhubarb. Here’s what you need to know before you harvest rhubarb plant, plus a few tips to make sure you’re getting the best harvest when you harvest rhubarb.

What Is Rhubarb?

Rhubarb is a precocious and prolific “fruit,” and it looks like stalks of celery colored a magenta or pinkish green. It has a much more tart flavor profile to it, and it makes it a great compliment for sugar in sweet dishes like compotes, crists, and pies. Rhubarb will also give you a slightly tart fruitiness to a range of savory dishes, and it pairs very well with poultry and pork. In the United States, you’ll find that rhubarb grows best in the northern states from Maine to Illinois to Washington. If you look around the world, you’ll find rhubarb growing in China and all across Europe. 

This plant is a member of the genus of plants called Rheum. It’s a decently hardy perennial vegetable, but people tend to use it more like they would fruits. In fact, a judge in New York in 1947 ruled that rhubarb is a fruit, so it’s classified as such by the U.S. Department of Agriculture. It’s a very popular addition to a range of backyard gardens, and it’s easy to grow. However, you should know that it’s hard to get rid of. It does need a cold winter to grow well and produce the brightly colored stalks in the spring months. 

You’ll only eat the rhubarb stalks with this plant because the triangular, large leaves are poisonous. They have a much higher concentration of oxalic acid than foods like cauliflower, broccoli, and spinach. Many people also think that this plant’s leaves also have a stronger unidentified toxin. You’d most likely have to eat a big amount of the plant’s leaves for it to be lethal. 

However, eating even smaller amounts can cause vomiting and nausea. To be on the safe side, don’t make a habit of serving or eating the leaves, and keep them away from your pets and children. Once you remove the leaves from the stalks, you can cut and trim them to suit your needs. Rhubarb gets sold by the pound, and you can expect to pay anywhere from $1.50 to $4.00. The price depends on whether or not it’s in season and how big the harvest was. 

Rhubarb by Rebecca Siegel / CC BY 2.0 Rhubarb is a very popular and large plant found in home gardens throughout the northern portion of the United States. It has a tart flavor that works well in savory and sweet dishes. 

Rhubarb Origins

Rhubarb originated in Asia, and it was first brought to Europe sometime during the 1600s. It is best planted in areas with a cooler climate, and this makes it a popular addition to northern gardens. It’s also decently easy to grow, but it requires a period of dormancy to grow well and give you a large amount of stalks. 

The stalks will give you a very tart, rich flavor when you cook them. Another nice point about this plant is that it’s a perennial. With the correct growing conditions, it’ll do well for years at a time, up to five or more. For this reason, you want to give your rhubarb plant a space on its own in the corner of the garden where it won’t compete with other plants and it can grow without being disturbed. It likes to have amended soil with a lot of decomposed compost or manure. This is why a lot of people plant it right by their compost bins or piles. 

Popular Rhubarb Varieties

There are several rhubarb varieties available, including some that grow green stalks that have a very sweet taste to them. You’ll generally find one of two popular varieties available to purchase in grocery stores and markets. The traditional, older variety offers greener, thicker stalks, and the slender-stalked, more intensely colored variety called hothouse rhubarb. The deep red coloring on the stalks can make a more attractive and brighter dish, but the brighter color also indicates that your rhubarb is more tart. The green stalks bring a very balanced, mellow flavor profile to your dishes. 

Rhubarb Nutrition and Benefits

The rhubarb stalks are very nutritious, and they have high amounts of manganese, calcium, vitamin K, vitamin C, fiber, and a range of antioxidants. It can help with digestion, relieve any constipation, lower cholesterol levels, and it can help soothe inflammation. 

Growing Conditions for Rhubarb

If you care for this perennial plant correctly and get the growing conditions right, it can give you seasonal stalks for up to eight years. It can grow into a very large plant, so you want to leave ample room between them to let them spread out. They need consistent water and fertilizer throughout the growing season to encourage them to continue to produce stalks. When the summer temperatures start to go up, you can add a layer of mulch around the plant’s base to help protect the new growth. Rhubarb won’t offer any stalks until after it establishes itself for a year, so your first crop will come during the second growing season. 

You can cut the stems with a knife when it comes time to harvest them, and they should be around a foot long at this point. You can also carefully pull and twist to remove the stalk, but this could accidentally cause root trauma. It can produce up to six pounds of stalks on a single plant in a growing season. 

Picking and Preparing the Planting Site

• You should take steps to eliminate weeds in the planting site before you plant your rhubarb. 
• Your site should have fertile but well-draining soil. Good drainage is necessary to prevent the plant from rotting, so you may want to amend the soil with bark or peat moss. 
• Rhubarb isn’t hugely picky about soil pH levels, but it’ll grow better if your pH is slightly more acidic at 6.0 to 7.0.
• This plant is a very heavy feeder and needs a large amount of organic matter to support growth. Mix rotted manure, compost, or anything with high organic matter contents into the soil.
• Plant it in a place that gets full sun. It will also tolerate partial shade, but it won’t grow as well. 
• Your planting zone should get around 40°F in the winter months and over 75°F in the summer months. 
• Plant it in a site where it won’t be crowded because each plant can get between two and three-feet across. 

How to Grow Rhubarb

• Water the rhubarb consistently and deeply. It needs sufficient moisture to do well, especially during the dry, hot summer months. 
• Add a heavy layer of mulch with straw to help discourage weed growth and retain moisture around the roots and base. 
• Overcrowding is a very common problem with this plant because people don’t realize that it gets so big. As a result, it can stunt the growth. Dig and split your rhubarb plants every three or four years during the late fall or early spring months. There should be at least one big bud on every division. 
• Remove the seed stalks as soon as you see them because they pull energy and nutrients from the plant that it could use to produce stalks or roots. 
• When the ground starts thawing in the spring, sprinkle a light layer of 10-10-10 fertilizer. 
• Remove all of the plant debris in the fall. Once the ground freezes solid, cover the plant with two to four inches of mulch and well-rotted compost. This will inject nitrogen into the soil that will kickstart the spring growth season. 

Rhubarb by Tony Buser / CC BY-SA 2.0 Growing rhubarb isn’t hard as long as you give it plenty of space to spread out so they don’t compete and end up with stunted growth. 

When to Harvest

You should only harvest stalks from established plants. If you just planted your rhubarb, wait until it’s had a year to grow before doing any harvesting. Nourish it with some homemade plant food and leave it alone this season.

Knowing when to harvest rhubarb is not an exact science because it will vary depending on your planting zone. Generally, the best time to harvest rhubarb is from April-June or whatever months your spring and early summer fall into.

You can tell when stalks are ready to pick by looking at the plant itself. Rhubarb doesn’t turn color and “ripen.” You need to look at and measure the length.

Stalks should be at least 10-12 inches long before you start picking any. Once the plant gets to this size, you’ll know that the plant has grown enough and will not be harmed when you harvest rhubarb.

This rhubarb plant is still emerging and is too small to harvest. As we note in this guide on how to harvest rhubarb plant, wait until stalks measure at least 10-12 inches before picking the stalk.

When to Stop Harvesting

Once you start to harvest rhubarb, you can keep doing it regularly for about 6-10 weeks as long as you don’t cut off too much.

From midsummer on (usually late June or early July), you’ll need to stop harvesting altogether or only pick a few stalks sparingly. This is because your plant is already starting to get ready for the winter.

Rhubarb uses energy from its leaves to store up for the winter season. If you keep harvesting all the way until fall, you risk killing the plant because it won’t have enough leaves to give it energy.

Because rhubarb likes cool weather, it won’t grow as much during the summer months anyway, so there won’t be much to harvest. When the cooler fall months come around, you may notice a surge in growth.

If this happens, you can safely pick 1-2 stalks from each plant as long as it looks healthy and you leave at least ⅔ of the plant intact. If you’re ever unsure, play it safe and don’t harvest the stalk. This will ensure you have a good harvest yield next spring!

Tools for Harvesting Stalk

Tools are not absolutely essential to harvest rhubarb since you can cut the stalks with your hands. However, they do make the job easier, especially if you have an older plant with tougher rhubarb stalks.

A pair of gardening shears or a sharp knife will help you cut the stalks and remove the rhubarb quickly and cleanly. They also make it easier to cut the rhubarb leaves off after harvesting, since the rhubarb leaves aren’t edible.

To make sure you don’t infect your rhubarb plants with any type of bacteria or harmful pathogen, always clean your garden clippers before or after use.

Simply rinse your shears under warm water and wash them off with a little dish soap (or baking soda for tougher spots). To get rid of any bacteria, dip the blades in a solution of bleach, white vinegar, or rubbing alcohol.

Dry your clippers with a rag so they don’t rust, and you’re ready to go!

Rhubarb by Dave Gunn / CC BY-NC 2.0 Harvesting rhubarb is something you can do all at once or stagger it out over four to six weeks. Cut cleaning to avoid damaging the root system. 

How to Harvest Rhubarb Stalk

Once your rhubarb plant has reached the right length, it’s time to enjoy them.

To harvest, grab one of the outer plant stalks right at its base. Pull the rhubarb stalk slightly away from the rest of the rhubarb plant, and cut the rhubarb stalk with your shears as close to the base as possible. Try to make a clean cut so that the plant can easily recover.

If you don’t have garden clippers (or forgot them), you can also grab one of the stalks at the base of the rhubarb and slowly pull it away from the plant while twisting. The stalk should break away, although the tougher rhubarb stalk might be a little resistant.

Harvest the outer stalks first, and cut or pull them off as close to the base of the plant as possible. Always leave at least ⅓ of the plant to keep growing after you’ve finished harvesting.

Be sure you don’t start pulling the plant up by mistake. If the stalk is being difficult, get a knife and cut it off at the base.

Any time you harvest, be sure you leave at least ⅓ of the plant intact. Once your plant bounces back from its first harvest, you can come back and pick the outer stalks again. If harvested correctly, plants can keep producing for up to 20 years!

Trimming and Storing Tips

After harvesting the rhubarb plant, be sure you trim off all the leaves and put them in your compost pile. The leaves are poisonous and should never be eaten.

You can wash and use the stalks immediately to make your favorite recipes or store them for later.

If you want to store your rhubarb, there are two ways to do it. For short-term storage, wrap in a damp cloth or paper towel and store them in a plastic or reusable bag in your refrigerator. Preferably, you want to store them in a bag that’s slightly open or has small holes so that there’s still air flow.

Use your freshly picked rhubarb right away in your favorite recipes or store them for later. Be sure you trim off the leaves, which are poisonous, and put them in your compost pile or yard waste bin.

They should be kept for up to four weeks in the refrigerator. Put in a glass of cold water to refresh them before using.

You can also freeze rhubarb for longer-term storage. Just chop the stems up into smaller pieces and freeze them in quart or gallon bags. Blanching is not required, but it can be done to better preserve the flavor and texture.

You can expect rhubarb to keep its fresh flavor for up to a year in the freezer.

Rhubarb by Sarah Braun / CC BY-NC-ND 2.0 You should carefully trim and store your rhubarb when you harvest it so it’s ready to go when you want to use it. 

More Tips on How to Harvest Rhubarb

You’re now all set to pick, store, and cook your rhubarb. Here are a few extra tips to make sure you get the most out of your plants:

• At some point, your rhubarb plant will start to flower, which will make the stalks tougher and more difficult to work with. Cut off the flower stalks when they appear to extend your harvesting season.
• After you finish harvesting in late June or early July, put some homemade compost around the roots to help your plants recover and give you a good yield next year.
• Water your plants during the summer months if you go through a dry spell. You can also apply mulch (especially if you get hot summers) to keep moisture in the soil. This helps your plants to recover and stay healthy after being harvested.
• Your rhubarb will likely keep getting larger over the years. Extremely large stalks can be tough, so divide your plants every 3 to 4 years to keep them to a manageable size. Just dig up the roots in early spring or fall (when the plant is dormant) and split in half.

How to Cook With Rhubarb

Rhubarb is one plant that is relatively easy to cook with. It’s essential that you discard and trim away the leaves due to their toxicity. Wash each stalk very well and trim away the dry ends. It may be tempting to peel away any fibrous skin you see as you cut up the stalks, resist doing this. The skin will hold a large amount of flavor and color. 

When you cook rhubarb, two things happen. The first thing is that the juices start to thicken and it’ll fall apart into shreds. If you cook your rhubarb heavily, you get a perfect jellied consistency that works for rhubarb jam. It’s also good for compotes and chutneys. You won’t get an attractive look if you try to arrange it in a tart or stir-fry. Adding it with quick heat will give you very tender but cohesive pieces with a glossy sheen and rich flavor profile. 

Where to Buy Rhubarb

You can find hothouse rhubarb available most of the year, and field-grown rhubarb is readily available during the spring months from April to June. In the Pacific Northwest, you’ll get a second yield between June and July each year. The shorter growing season of this plant means that it’s a good idea to buy and enjoy it when you see it. You can find it in grocery stores and in farmer’s markets, and a lot of vendors sell it loosely by the stalks. The stalks are usually as big as a large celery stalk, and you can buy them by the pound. At farmer’s markets,  you can buy them in bulk if farmers had a good growing season or a bumper crop. The stalks should have a shiny skin and be heavy and crisp. Avoid dry, fibrous, and rubbery stalks. 

You can grow and harvest it in your garden at home too. Leave the plant alone for the first year. During the second year, you can take a smaller harvest, and you can harvest the full crop during the third year. The stalks should be at least an inch thick. You can harvest it all at one time, or you can stagger it over a four to six week period. Unless impacted by diseases or pests, the plants can survive as long as 15 years. 

When is Rhubarb in Season?

Rhubarb is only around for a short few months during the year, so grab it when you can. Generally speaking, rhubarb will come into season from mid-spring to early summer. In the United States, it can be difficult to find rhubarb unless you live in the northeast region of the country. 

Rhubarb vs. Chard

When you first look at it, it’s very easy to confuse this plant with chard, especially if you see ruby red chard. It also produces bright red stems and you’ll find it in bundles with rainbow chard. The two things are extremely different though. Chard is actually a member of the beet family, but you don’t use it as a root vegetable. 

You can eat the stalks on both plants, but you can only eat chard’s leaves. Also, if you were to compare them side by side, you’d notice that chard has leaves with more prominent veins. The color also extends all of the way through the leaves. Rhubarb’s veins will blend in much more with the leaf, depending on the variety. Chard tastes more like spinach, and rhubarb can be extremely tart. 

Is Rhubarb Poisonous?

The big green leaves on this plant have a very high concentration of a compound called oxalate. If you were to ingest larger quantities of it, it is toxic and can cause kidney stones. If you have prior issues with your kidneys or kidney stones, you should be even more careful to avoid the leaves because they’re more poisonous to people who have kidney damage and can’t get rid of this compound effectively. 

Common Pests and Diseases

Luckily, diseases or pests are rarely an issue with rhubarb because it’s so hardy.  However, they could have a problem with:

• Crown rot
• Rhubarb curculio (beetle)

Frequently Asked Questions

Rhubarb by Elizabeth Thompson / CC BY-NC-ND 2.0 Since rhubarb is so popular, there are a lot of common questions surrounding this plant in general, as well as growing and harvesting it. 

1. Can you eat rhubarb raw?

Before you cook any rhubarb, you should try it raw. You do want to be sure that you remove all of the leaves before doing so. You can dip the stalk into sugar or another sweetener like honey, agave nectar, or maple syrup to help mellow out the plant’s tartness. 

2. Is rhubarb poisonous to pets?

Rhubarb can be poisonous to cats and dogs. Eating the leaves can cause diarrhea, vomiting, mouth irritation, pawing at the mouth, and increased drooling or salivation. 

3. Does rhubarb spread?

Rhubarb will spread, and this plant doesn’t tolerate a lot of crowding. The stalks and leaves will get much bigger and healthier if you give them plenty of space. You’ll only need a few plants for your garden. Space the rows three feet apart if you want to plant in larger quantities. 

4. What should and shouldn’t you plant with rhubarb?

A few good companion plants for rhubarb include cabbage, turnips, kale, strawberries, beans, broccoli, garlic, onions, and cauliflower. You don’t want to plant pumpkins, melons, cucumbers, or tomatoes next to rhubarb because they can stunt the rhubarb’s growth. 

5. How do you tell if rhubarb is ripe?

Rhubarb is ready for you to harvest when the stalks get between 7 to 15-inches long. The leaves should also fully open at this point. Don’t rely on the stem color for an indication of how ripe it is because they can offer different shades of red, depending on the variety you planted. 

6. Where is the best place to grow rhubarb?

You should grow your plant in the sun in light moist but rich soil in USDA hardiness zones six and up. It should have some protection from the hot afternoon sun, and it won’t do well in soggy soil because it can develop root rot very quickly. 

By following these guidelines for how to harvest rhubarb and keeping your plants healthy, you’ll likely be enjoying freshly picked rhubarb for years to come!