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How to Harvest Rhubarb in the Home Garden

Our garden is the farm's pride and joy. We love spending time in it, and preparing meals out of our fresh produce.

Introduction

Rhubarb is one of the easiest and most prodigious perennials you can grow in your garden. Not only that, it is incredibly easy to harvest. Once planted, you will be rewarded with an abundant yield for years to come.

While not ideal for eating raw (though one of our customers at a farmer’s market bought a bunch of the tender stalks and walked around snacking on them), rhubarb is delicious when baked into pies, crisps, or made into sauce.

Let’s look at how to tell when your rhubarb is ready and how to harvest it.

What Parts of the Rhubarb Plant Are Edible?

Rhubarb is grown for its sour, edible petiole (or stalks). Do not eat the leaves as they contain high amounts of oxalic acid which can cause vomiting, diarrhea, and ultimately kidney failure.

All parts of the plant, including the stalks, contain oxalic acid which is where the sour flavour comes from. However, you would have to eat a lot of rhubarb for it to cause a problem.

Is Rhubarb Poisonous in the Fall?

This is a widely disputed topic, and I’m sure many of us grew up hearing that it was, in fact, poisonous after mid-summer. This is an old tradition based on the thought that the oxalic acid would increase over the summer. This is probably untrue, and I have personally eaten rhubarb from my garden in August.

However, there is some evidence to suggest that when a rhubarb plant’s leaves wilt or are frosted that the oxalic acid may transfer to the stalks.

If in doubt, play it safe and don’t eat it.

Can Rhubarb Be Harvested the First Year?

The answer to this depends on how you started your rhubarb. Rhubarb can be grown from a root cutting, A bare root, a potted plant, or from seeds. Each one takes a different amount of time to establish before it is ready to harvest.

Root Cutting: The most common and fastest way to grow rhubarb is from a root, or crown, cutting. It is simply a chunk cut off from the root of an already established plant. This new piece of crown is usually planted in the fall or early spring, and you can usually get a light harvest from the plant the first year.

Bare Root or Nursery Stock: You can also start your rhubarb by buying a bare root or a small potted plant from the nursery. Either of these should not be harvested the first year. They can be harvested lightly the second year and as normal each subsequent year.

Seeds: When starting rhubarb from seeds, it usually takes 2 to 3 years before the plant is large enough to harvest.

Harvest Rhubarb From Early Spring To Mid-July

Rhubarb is a cool-season plant that grows prolifically in the spring and early summer. Its growth and quality tapers off during the heat of the summer. Rhubarb stalks will quickly wilt and rot in the summer. There are a few ways you can harvest your rhubarb

Early spring to mid-July is the prime rhubarb season. Because it is such a quick-growing plant, you will probably get several harvests during this time. You can either pick a few stalks or harvest the whole plant.

1. Pick Stalks as Needed

Throughout the growing season, you can pull stalks from the plant as you require for your culinary efforts. It is often a good idea to thin out your plant, anyways, to keep some of the larger stalks from becoming over-mature.

2. Gather the First Harvest

In mid to late spring, your rhubarb plant will probably be large enough to harvest the entire plant. It might be a good idea to leave a few of the small stalks and leaves on the plant. This isn’t necessary but it can help the plant regrow a little faster.

3. Gather the Second Harvest

A few days after your first harvest, dozens of new leaves will shoot up. By the early summer, the rhubarb will have regrown enough for a second harvest. This time, you don’t need to worry about leaving any leaves. While regrowth will be slow, the plant will still send up enough foliage to protect it over winter.

Depending on your climate, you might be lucky enough to get a third harvest before the heat of summer. In our own Zone 2b climate, we can usually begin picking stalks in late May. Our first harvest is generally mid-June and our second harvest is early to mid-July.

What Time Of Day Is Best To Harvest Rhubarb?

As with most plants, rhubarb is best harvested in the morning. This is because the plants take on water and convert starches into sugars during cool nights.

However, the thick leaves and tough stalks of the rhubarb plant are not as susceptible to wilting from the heat as some of the more delicate vegetables in your garden. If you do harvest during the heat of the day, protect the newly picked stalks from the sun by keeping them in the shade.

Yield Of A Rhubarb Plant

How much rhubarb do you get from a single plant? The yield of your rhubarb plant will vary greatly depending on the variety, growing conditions, and your climate. Most references online say to plant 2 to 3 plants per family member, and you should expect about 1kg to 3kg (2-6 lbs) per harvest.

In our garden, we get upwards of 10kg (22lbs) per harvest and one plant is more than enough for our family.

How to Tell Rhubarb is Ready to Harvest

The best way to tell if rhubarb is ready is by the size of the stalks. Here are a few indicators if your rhubarb is ready or not:

1. Choose the Best Size

The ideal size for a rhubarb stalk at harvest is 30cm (12 inches) long and about 1.25 cm to 2.5 cm (1/2 to 1 inch) in diameter. That being said, we have harvested them at half the size (these are the best for eating raw) and some over a meter long and as thick as a small tree.

2. Don’t Rely on Colour

The colour of the rhubarb stalks is not an indicator of ripeness but is determined by the variety you are growing. Some rhubarb varieties are green, some are deep red, and others are a red/green mix.

3. Wait until there are enough stalks

It is best to wait until there are at least 10 stalks on the plant before harvesting. Otherwise, you might set the plant back too much and delay its growth. This is especially true if your plants are young or if it is still very early in the year.

Rhubarb Flowers

At some point, your rhubarb plant will probably produce flower buds and go to seed. This usually happens in summer, but rhubarb will often send up flower stalks in late spring. The flower stalks themselves are Woody and inedible but the rest of the plant is fine, and the flowers do not affect your harvest.

Once the plant flowers, all of its energy goes into seed production. For this reason, it is best to remove any early flower buds to encourage new stalk growth.

Once you are done harvesting you can leave the buds to go to seed as they are quite pretty or you can remove them. We have removed the buds and left them with equally good results.

A rhubarb flower

A rhubarb flower

How To Harvest Rhubarb

Rhubarb is easy to harvest, and the only tools you need are your hands. Here is a step-by-step guide to harvesting your rhubarb.

Step 1. Twist Off the Stalks

Take a firm grip on the stalk as close to the base as possible. Twist the stalk while pulling. Oftentimes the stalk will come with a gentle tug, but sometimes you really have to tug on it.

Twisting off the stalks is much preferred over cutting. Twisting them off can help encourage new growth while cutting leaves behind a small stub that will quickly rot and leave a gooey mess.

Step 2. Remove the Leaves

Twist or cut off the leaves. To twist them off, grasp the stalk with both hands just below the leaf and twist while pulling your hands apart. You can also use a sharp knife or a pair of garden shears to cut the leaf off.

Add the leaves to your compost or use the largest ones as a mulch to shield the soil and suppress weeds around your other vegetables.

Step 3. Remove the Base of the Stalk

Sometimes, part of the plant crown will be attached to the base of the stalk. Remove this like you would the leaves, and put the cut end in the compost.

Storing and Preserving Rhubarb

Rhubarb stores and preserves very well. Here are the best ways to keep your harvest:

Store in the fridge: Freshly harvested rhubarb will last 2 to 4 weeks in your refrigerator. Leave the stalks unwashed (or dry them well) and whole if possible.

Frozen: Slice your rhubarb into pieces about 1 cm (1/2 inch) wide. Freeze them on a cookie sheet and then put them in an airtight, freezer-safe container.

Frozen rhubarb will last for about a year, or until it becomes icy and freezer burnt.

Dehydrated: Cut your rhubarb into pieces about 1 cm (1/2 inch) wide and dehydrate them according to your dehydrator’s instructions. They can also be dehydrated on a tray in the oven.

Put the dehydrated rhubarb into a jar or other airtight container and store it for about a year.

Canned: There are several ways to can rhubarb and many delicious recopies to make. Make sure you carefully follow the directions of your canner.

Conclusion

Knowing when to harvest your rhubarb is important to ensure you get the best tasting, most nutritious rhubarb possible. I hope this article had shown how easy it is to grow and harvest rhubarb of your own.

An established rhubarb plant is nearly indestructible, and it is very hard to kill by accident or mismanagement. Our rhubarb has been through a lot, both from us and from the elements, yet it still thrives and produces huge amounts of stalks each year.

Once your plants are established, you had better stock up on sugar so you can turn this sour vegetable into countless delicious desserts.

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2021 Bellwether Farming

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