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Forcing Rhubarb: The Trick to Sweeter Stalks & Early Harvest

Forcing Rhubarb: The Trick to Sweeter Stalks & Early Harvest

Are you thinking about promoting early growth in your rhubarb plants this year? Check out this complete guide on how to achieve it effectively!

How do you force rhubarb? Forcing rhubarb to grow quicker, taste sweeter, and be ready for early harvesting is simple: deprive it of light during the times of the year that they are at their most active growth phases. Isolating rhubarb from the light forces accelerated growth of the plant as it attempts to reach the light.

Read on below to learn the trick to sweeter stalks and early harvests!

Forcing Rhubarb – What To Know

Rhubarb naturally grows during the early spring, and the harvested period lengthens from mid-spring to mid-summer.

Forcing rhubarb may not be very common, but is a sure-fire way to an earlier harvest and sweeter rhubarb stalks.

What Forcing Rhubarb Means

Forcing rhubarb means that you are going to make them grow sooner by excluding them from the sunlight. 

Sunlight is necessary for the plants to photosynthesize. A desperate attempt of the plant to reach sunlight will make them grow at least a month earlier, sometimes even sooner. 

The most common way to cover the rhubarb buds is by using a large pot. In cold temperatures, use an old carpet or bubble wrap to totally isolate the pot while providing warmth. 

Benefits of Forcing Rhubarb

Among the main benefits of forcing rhubarb, you’ll have of course the chance to enjoy your harvest sooner, but that’s not the only benefit as the taste and texture of the rhubarbs will be different as well. 

Non-forced, traditional rhubarbs have a more bitter taste than forced ones. When forced, the stems stretch and discolor.

These pale stems need less sugar to balance the tartness and also have a texture that is more tender, making the taste much more delicate and sweet. 

When To Start Forcing Rhubarb

Rhubarb plants grown in the traditional way start growing in the early spring, and they are ready to be harvested from mid-spring to mid-summer.

If you want to force rhubarbs, you should start the process of covering the crowds in late winter. 

That way the rhubarb will be fully grown and really to be harvested a whole month sooner or even before that if you can lift sections of your rhubarb’s crowns and take them to a warm place. 

How Long Until Forced Rhubarb Is Ready for Harvest

Forced rhubarb plants will take 7 to 8 weeks till they are ready to be harvested. It would normally take longer than that, but the need to reach for sunlight will make them grow faster. 

When the stalks are 7 to 12 inches in length, you can gently pull them from the base of the crown.

It’s important to remove the leaves as they have a high amount of oxalic acid, which makes them toxic for consumption. 

After that, the rhubarb will be ready to be washed and cooked.

Dos and Don’ts When Forcing Rhubarb

The crowns that have been used for forcing will need time to recover. Don’t harvest them the following year. Remember the forcing process is not natural, and it weakens the plant. 

When a plant is weak, the stems don’t grow strong, and it is more susceptible to diseases.

If you have the space, you can grow more than one plant. That way you’d be able to use one for forcing one year while the other recovers.

How To Force Rhubarb

Forcing rhubarb is actually very simple. Read on below to learn the step-by-step process and other important considerations to know about forcing rhubarb. 

1. Identify and Clear the Area

The first thing you need to do is identify if the rhubarbs are ready to be forced. The crowns have to be mature. 

Then, you need to clear the area around the rhubarb crowns while removing all leaves and weeds that might have accumulated.  

2. Prepare the Soil

You’ll also have to prepare the soil by adding homemade compost or a mulch of well-rotted manure around the plant. 

This will boost the nutrient levels of the soil, which will aid the growth of the rhubarb stalks. Make sure not to bury the crown, or it might rot. 

3. Cover

The process of forcing rhubarb consists of excluding them from sunlight. To achieve that, you’ll have to cover the crowns. This is perhaps the most important step.

You can use a rhubarb forcer, a large pot, or a tote-type container. If you’re using a pot, remember to cover the holes so no light can get in.  

4. Protect From the Cold

In colder areas, you’ll need to insulate the pots covering the rhubarbs. You can use bubble wrap, a thick layer of straw, or even an old carpet to cover them. 

This warmth not only protects the plants but will also speed the forcing process. 

5. Harvest and Enjoy

Once the stems have grown 7 to 12 inches in length, they’ll be ready to be harvested. It will take approximately 8 weeks for them to get to this size. 

Once they have, you just pull gently from the stem to separate them from the base of the crown and remove the leaves. 

What To Do With Rhubarb Plants After Forcing 

After you’ve picked your harvest, the plant will need to recover. If there are any leftover stalks, they will naturally die after the first frost. 

Keep things neat by trimming the plants, cutting the remaining stalks, and removing the leaves. 

Don’t Force the Following Year

The forcing process isn’t natural, and it weakens the plants. It’s not recommended to force them 2 years in a row. When the plant is weak, the stems don’t grow as strong and they are more vulnerable to diseases. 

Consider growing more than one plant so you can force one each year.

Fertilize After Forcing

Rhubarb needs soil that is rich in nutrients and  drains quickly so it can recover after being forced. If left unattended on the cold wet soil, the crown will rot. 

After forcing, you’ll need to turn over the soil and help improve its structure and fertility by applying fertilizer.

Harvest as Normal the Next Year

As it takes at least two years for a rhubarb plant to recover, the following season you can grow them normally. 

This means your harvest period will be from mid-spring to mid-summer. The stems will be darker, and the taste will be tarter than the forced ones but still delicious.

Related Questions:

Is Forced Rhubarb Sweeter?

Forced rhubarb is lighter in color, has a softer texture, and yes, also tastes much sweeter than non-forced rhubarb.

What’s the Best Fertilizer for Rhubarb?

Compost, manure, and phosphorus are the best organic elements to fertilize rhubarb with. If you aren’t gardening organically, using a product with an NPK of 10-10-10 for rhubarb is highly suggested.

Final Thoughts

Forcing rhubarb is an easy process once you understand it.

Blocking the light from reaching the plant and preventing photosynthesis from occurring causes the plant to kick into overdrive as an attempt to “breakthrough” the “soil” and reach the sunlight.

Hopefully, the information and step-by-step guide above helps you force an early harvest of sweeter stalks from your rhubarb!