Where to Plant Rhubarb: Soil and Light Requirements
Rhubarb is a longtime garden favorite for its lush, bright red, and tart stems. It’s perfect for cooking into pies, jams, and preserves. Because it’s a long-lived perennial, choosing a proper planting site is essential for a productive crop. Learn what this veggie needs to thrive with this easy-to-follow guide.
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Garden rhubarb is the first crop you should plant! It’ll produce dozens of healthy stems annually that you can harvest throughout the growing season. Perennial vegetables are essential in the home landscape—without them, you’ll have to sow annual crops each year and spend much of your time cultivating seedlings.
Rhubarb, like asparagus, requires a few years to establish itself. After establishing, it’ll tolerate repeat harvests from spring through fall. Fresh transplants need a year or two of unchecked growth before they’re ready for harvesting.
Whether using raised beds, planters, or the ground to grow rhubarb, you must plant these veggies in a place where they have plenty of sunlight, moisture, and fertile soil. With a little preparation and care, you’ll be growing lush harvests in no time!
What Is Rhubarb?
This vegetable is a perennial, rhizomatous plant with long, red stems and wrinkly, green leaves. The stems are edible. However, the leaves, roots, and rhizomes are toxic. They contain high levels of oxalates and deadly anthrone glycosides, which are poisonous in high doses. The stems are completely safe to eat.
The garden hybrids we cultivate today are the descendants of past species. They’re known botanically as Rheum x hybridum, and they grow well in USDA hardiness zones 3 through 8.
Other types of rhubarb exist, like species and wild forms, though the hybrids offer the highest yields and best-tasting stems. Some have green stems instead of red ones, while others grow thin or wide stalks. Choose your favorite variety, as you’ll have to eat it for decades after planting it!
The Ideal Site
Because rhubarb will grow for many years in the same location, choosing a proper site is key for its long-term success. Ensure the soil, light conditions, and moisture levels are optimal for healthy growth, and check them annually to verify they’re still in the optimal ranges.
Soil
This crop appreciates loamy, well-drained, and fertile soil. Garden soils are ideal if they’re rich in nutrients and well-structured. Dense clay and free-draining sand can be problematic, as they’re less than ideal for these plants. Consider amending poor soils with compost or leaf mold to boost them.
Organic amendments like compost release nutrients, microbes, and beneficial critters like worms into the dirt. The microbes break down organic matter into smaller particles that plants can use, while the worms create air channels in the ground that help with drainage. Humus, a natural byproduct of worms, is incredibly absorbent and essential for a healthy soil ecosystem.
Drainage is especially important if you’re growing this crop in containers or planters. Use a well-drained potting mix with perlite, vermiculite, or pumice.
Soil pH is also important for optimal harvests. Grow rhubarb in soils with a pH between 6.0 and 6.8. Use garden lime to raise the pH or sulfur to lower it into the optimal range.
Exposure
Rhubarb grows best in areas with full sun exposure. Grant it six or more hours of direct sunlight. Consider giving your specimens afternoon shade if you garden in warm, southern states with more than eight hours of direct sunlight.
Rhubarb is perennial in zones 3 through 8. It can grow well as an annual crop in zones 9 and 10 during the cool months, and it can also survive winters in zone 2 with extra protection. Overwinter potted specimens in a garage or protected patio, and protect outdoor specimens from frost with greenhouse plastic or frost cloth.
Forced rhubarb is a delicacy that growers create by shading the stalks from the sun. It causes yellow leaves and long, thin, and pink stalks. The forcing process causes the stems to grow sweeter than they would be if they were exposed to direct sunlight. Use a large, black container or similar sun-blocking object to shroud the stalks in the dark.
Irrigation
Consistent moisture is key for healthy rhubarb growth. Ensure your specimens can access water from natural rainfall, overhead irrigation, or drip systems. Drip irrigation systems are the most water-efficient, though their rubber tubes can sometimes plug up with dirt.
In warm, dry climates, rhubarb requires water once or more times a week during the hot summer months. Ensure the soil stays moist, but not soggy, from spring through fall. Avoid growing this veggie in especially dry or swampy conditions, and keep its roots consistently moist.
Planting Rhubarb
Planting rhubarb is as easy as 1-2-3. Choose where to plant, prepare a planting hole, and transplant the rhubarb starts. No matter what you’re growing them in, proper preparation is crucial for long-term success.
Choose a Location
Considering soil, light, and moisture, choose a good location to grow your rhubarb. This perennial grows well in the ground, raised beds, and containers or planters. The plant is small when young, though over time, the rhizomatous roots form a giant crown.
Raised beds are perfect for growing rhubarb, as they drain well and you can amend them easily with compost. Opt for sturdy, long-lasting metal raised beds or easy-to-set-up wooden ones.
Each plant requires three to four feet of space from the others. If you’re planting more than one plant, consider choosing a site with plenty of space that can accommodate multiple rhubarb specimens.
Containers and planters can hold these plants, so long as they’re large enough to hold the rhizomes. You’ll need to repot the crop every few years to ensure the roots have fresh soil to grow into.
Prepare the Site
In-ground beds require rich, well-drained soil where rhubarb plants can thrive. Amend them with compost a few weeks before planting to ensure they’re fit for your crops. Fill raised beds or containers with potting soil, or use a homemade, well-draining mix with organic materials and drainage components.
Prepare the site for transplanting in early spring or late fall. Dig a hole as deep and twice as wide as your plant’s rootball. Avoid cramping a large rootball into a small hole, as the cramping can cause poor growth in spring and summer. Grant your specimen plenty of space so its roots can spread wider and deeper each year.
After preparing each hole, remove your plants from their containers. Carefully unpot them so as not to break off too many roots. Loosen the bottom and sides of the rootball so it has loose root fragments that can latch onto your garden’s soil.
Transplant Rhubarb
After all the preparation, it’s time to plant your rhubarb where it will live for the next 10-15+ years! Place the rootball inside the hole, then backfill the soil over the roots so you completely cover them. You want the soil in the hole to be level with the ground. Water the site well after planting to see if the soil settles. If it sinks below ground level, add more on top of the roots.
Young plants need a few years of healthy growing before you can harvest them. Harvest a few stalks in the first and second years, then leave the rest to grow and flourish. After the plants establish themselves, you may harvest the stalks when they reach maturity early in the growing season. Depending on the variety, they’ll extend one to two feet long.
Stop harvesting after midsummer to let the rest of the leaves photosynthesize and gather energy for next year. You may harvest more and more stalks each year as your plant matures.
Frequently Asked Questions
Where is best to plant rhubarb, in the sun or shade?
Rhubarb grows best with full sun. It may benefit from afternoon shade in warm, southern states with intense, hot summers.
What does the rhubarb plant look like?
This vegetable looks like Swiss chard, though its leaves are much larger and wider. It has ruffly green leaves and red or green chard-like stalks. The stems sprout from a tough, rhizomatous base.
Can you plant rhubarb in a raised bed?
Yes, you can! This is a great way to cultivate this plant, especially if your garden soil is compacted, sandy, or dense clay.
