Horticulture Magazine

Experts Reveal How To Force Rhubarb For An Early Crop (Make It Grow Faster And Earlier)

two traditional clay forcing jars next to rhubarb plants
By CHRIS LEE
Chris Lee, MA - Gardening Writer

Chris is a gardening writer and nature enthusiast. He graduated from Oxford Brookes University in 2022 with an MA in Psychology. Chris works with the Leeds Green Action Society, helping their food cooperative by growing various fruit and vegetables on their two allotments in Hyde Park, Leeds.

/ Updated October 24th, 2024
Reviewed By COLIN SKELLY

Colin is a Horticulturist and Horticultural Consultant with experience in a range of practical and managerial roles across heritage, commercial and public horticulture. He holds the Royal Horticultural Society’s Master of Horticulture award and has a particular interest in horticultural ecology and naturalistic planting for habitat and climate resilience.

/ Meets Our Editorial Guidelines

Depending on the circles you move in, rhubarb can be a criminally unsung crop.

This vivacious vegetable (yes, it’s a vegetable!) grows big and proud, its characteristic pink-red stalks erupting out of the ground and into the sky.

When picked and trimmed of its leaves, the stalks are delicious and versatile.

rhubarb plant in soil
Never a dull moment with rhubarb

One thing that makes rhubarb a popular crop for those of us in the know, is how easy it is to grow.

Rhubarb needs little care or attention, evidenced by how often you’ll find it in the wild if you know where to look.

It grows well in warm and dark conditions, and has a long harvesting season that can start in winter if you know how – great for incorporating into your growing calendar to ensure you’ve got something ready to harvest for as much of the year as possible.

In this article we’ll teach you how to force rhubarb: a technique that brings the start of the harvesting season forward slightly.

This should be of interest whether you’re a long-time fan or a complete amateur.

What Is Forcing?

Put simply, forcing is a way to make rhubarb grow faster and earlier in the year than usual.

Forcing is basically tricking the plant into thinking it’s spring, encouraging it to grow more quickly towards what it thinks is the warm springtime sun.

This is achieved by simulating warmer growing conditions during winter, and it’s surprisingly easy to do.

How To Force Rhubarb

There are only a few steps to forcing rhubarb, none of which are difficult.

1) Prepare The Area

First up you’ll want to clear the area at the base of a fledgling rhubarb plant.

This means removing weeds, old leaves, and any garden detritus that may have gathered around.

2) Add Some Compost

Next you need to spread a little compost around the rhubarb, taking care that it doesn’t actually touch the stalks.

Doing so can burn the crop and hinder its ability to grow.

Just put it in a ring a couple of centimetres away from the plant.

3) Cover Your Rhubarb Plants

This is the crucial step: you’re going to cover your rhubarb with a pot, trug, bucket, or similar container.

Choose something opaque to block out all-natural light, and ideally with only one hole to allow airflow.

Terracotta pots being used for forcing on a vegetable patch
Terracotta pots make for great forcing

If your covering is made of a light material that may get blown away in strong winds, make sure to weigh it down with a brick or something similar.

Plastic plant pots and buckets will definitely require weighing down to prevent them from being blown around your garden once the wind picks up.

How Long Does Forcing Take?

It takes anywhere over three weeks to force rhubarb.

When you check under the containers you’ll see thick pink stems, and these are ready to pick when they’re upwards of about 18cm.

The longer you leave your rhubarb the bigger it will get, although check in occasionally to make sure things aren’t getting too cramped.

Depending on how many rhubarb plants you have and the weight of the container, you may even see the stalks lifting the container off of the ground!

As we said earlier: rhubarb is very enthusiastic.

Remove The Leaves

Before you do anything with your rhubarb, remove and dispose of the green leaves.

What Else Do You Need To Know?

Now we’ve introduced the technique for forcing rhubarb (we told you it was easy!), here are a few things that should help you to see better results.

Number one: where possible, only force established rhubarb plants as the process is quite intensive, and younger plants can take longer to recover.

Once you’ve forced a rhubarb plant and harvested the resulting crop, don’t harvest again from the same plant for the rest of that year, even if it grows decent-looking stalks.

You need to give the plant time to rest to put it in best stead for a strong and healthy harvest in subsequent years.

man holding rhubarb crop in hands
Follow these steps to keep your rhubarb crop in good condition

Don’t worry about running out of rhubarb early if you force your crop though: it’s easy to stagger things to give yourself multiple harvests.

To do this, just leave some plants uncovered to grow at their natural pace.

Your forced crop will be ready within a few weeks of being covered, and you can harvest the remainder as and when it starts to look ready.

For a plant with a long harvest season, sometimes up until late August, this gives you a lot of flexibility.

You can also split rhubarb to give yourself a greater number of plants to grow.

Once you start experimenting with rhubarb – both in terms of growing techniques and recipes for your harvest – we’re sure you’ll grow to love it.

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