This Easy Rhubarb Forcing Hack Gives You an Early Crop Every Year – and Costs Almost Nothing to Do

Although it’s technically a vegetable, rhubarb (Rheum rhabarbarum) is widely consumed as a fruit in desserts such as crumbles and pies, as well as a preserve. Strawberry rhubarb pie is a particular summer favorite. You can grow rhubarb in USDA zones 3-8, and enjoy a spring harvest of these tart, tasty stalks in the second year after starting plants from crowns.

Once these perennial vegetable crops are established, rhubarb care is delightfully straightforward. But have you ever tried the sweetened stalks of forced rhubarb? Indeed, did you even know you can enjoy earlier spring harvests with this clever cheat, designed to fool the plant into early stalk production? Forced rhubarb is the most flavorful and tender rhubarb you can enjoy, and it’s utterly perfect for pies. What’s more, it’s so simple. Here’s how to master forcing rhubarb in 3 easy steps.

Why Force Rhubarb?

The obvious benefit of rhubarb forcing is getting an earlier rhubarb harvest. You can expect to be able to pull out tasty stalks 3-6 weeks earlier than if left to develop and mature naturally. Forcing these tart-and-tasty perennial vegetables might sound like a pro gardening move, but it’s oh-so-easy, and you can try it on several rhubarb varieties. It’s also cost-effective. You can use whatever you have to hand to cover your plants. There’s no need to buy any costly additional tools or materials.

What not all gardeners realize is that these early stalks also taste better after forcing. The exclusion of light means they grow pale and tender, which impacts flavor. Rather than the tartness of traditional rhubarb harvests, forced rhubarb stalks have a delectable sweetness that trumps stalks harvested at the usual time. This makes them perfect for pies, crisps, crumbles and a host of spring and summer desserts.

How to Force Rhubarb

Rhubarb forced for earlier harvesting is not something veggie growers tackle in the first few years. Forcing rhubarb may seem a little ‘out there’ but it isn’t a complicated process if you follow some simple steps. The only warning is not to try forcing very young rhubarb, so never attempt to harvest a rhubarb in its first year. Plants need time to grow and develop. In the second year, you can harvest lightly. By the third year, you can harvest fully and try the forcing method for earlier stalks.

For established plants, this is a great hack for faster harvests. Rhubarb is often one of those perennial crops you plant and forget, but this hack could change the way you harvest rhubarb and will certainly elevate your taste expectations! So just follow these easy steps.

1. Ensure a Good Winter Sleep

Resist the urge to start forcing your rhubarb too early. Rhubarb is a cool-season crop, and it needs a period of cold temperatures to eventually break the dormancy phase and begin to grow. Rhubarb will only grow successfully when it has a continuous period of temperatures below about 40 degrees Fahrenheit (4°C).

This winter sleep period should last for at least 6-8 weeks, so don’t start force the process too early. The ThermoPro TP60 Hygrometer Outdoor Thermometer, available from Amazon, is a useful way of gauging outside temperatures as well as humidity.

2. Provide Darkness

When it’s time, begin forcing your rhubarb by placing an opaque container over the crowns to create darkness. Make sure you do this after chilling first. People often use dedicated forcer pots, but you don’t have to use one of these. A bucket, garbage can, old chimney pot, or large clay pot will work. Just make sure the container is opaque (preferably dark if made of plastic) and held in place so it doesn’t blow over. You can get Heavy Duty 45 Gallon Plastic Trash Cans from Walmart.

The darkness forces the rhubarb stalks to grow as they search out light. The energy stored in the plants’ rhizomes is adequate to promote this growth. The result is taller, thinner stalks that are ready to harvest. They’ll also have less oxalic acid, making them taste sweeter and less sour.

3. Give Plants a Thermal Boost

The container placed over rhubarb crowns may be enough to force early, sweet stalks, but you can improve the odds by increasing the temperature around them. Pile up leaves or mulch around the covering container to trap heat in the soil and around the crown.

Use an organic mulch like Back to the Roots Premium Organic Mulch from Amazon, or organic material, aged manure, or straw from your garden. Add around the base of the container to trap soil heat. This extra layer acts as a thermal boost, and will help to mimic warmer spring temperatures sooner, resulting in even earlier growth.

Golden Rules for Forced Rhubarb

Forcing rhubarb is easy and effective, so once you’ve done it you will want to try again and again. However, resist the urge to force each rhubarb plant every year. The process is a little stressful for plants, so you need to adapt a ‘year off’ approach and alternate the process for each plant every two years. Force one crown this year, but next year let it rest and force a different rhubarb plant. If the stalks are growing too thin and weak, you’re overdoing it. Let the plant grow stronger and replenish its energy reserves before you try forcing again.

Another golden rule applies to harvesting. Don’t make mistakes which can damage the plant. The best way to harvest rhubarb stalks is by twisting and pulling. Don’t cut the stalks, as this leaves the plants vulnerable to disease. Remove leaves right away, as these are toxic. Add leaves to your composting area or dispose of them as you would any other yard waste.

Rhubarb Care Essentials

Just a few gadgets and conditioning treatments can help you maintain optimal forcing conditions and guarantee the tastiest rhubarb.

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