15 Rhubarb Growing Tips for Thick, Healthy Stalks

Rhubarb is an often overlooked but incredibly rewarding perennial for home gardeners. Its tart, bright pink stalks and dramatic foliage add both ornamental value and culinary potential to any garden space.

Many gardeners struggle with producing substantial rhubarb stalks, ending up with thin, stringy growth that hardly seems worth the effort. The difference between mediocre and exceptional rhubarb often comes down to a few key growing practices that influence stalk development.

If you’re looking to grow robust rhubarb plants that will feed your family for years to come, these tried-and-tested tips will help you avoid common pitfalls and fast-track your way to a bountiful harvest of thick, healthy stalks.

Plant in the Right Location

Rhubarb is a long-term investment that can produce for 10-15 years or more, so choosing the right planting location is crucial for those thick, healthy stalks you’re after.

These plants need full sun to thrive (at least 6 hours of direct sunlight daily). While rhubarb can tolerate partial shade, you’ll get significantly thicker stalks on plants that receive more sunlight. In particularly hot climates, providing afternoon shade can prevent stress during the hottest part of summer.

Soil drainage is non-negotiable for rhubarb. These plants hate wet feet and will quickly rot if planted in poorly drained soil. If your garden has heavy clay, consider planting in raised beds or amending the soil heavily with compost before planting.

When choosing your planting site, remember that rhubarb is a sizable perennial that can spread 3-4 feet wide when mature. Give each plant plenty of space (at least 3 feet between plants) to ensure good air circulation and room to grow.

Prepare the Soil 

Rhubarb is a heavy feeder that appreciates rich soil. Since these plants will occupy the same spot for many years, taking time to prepare the soil before planting pays dividends for seasons to come.

Start by digging a hole approximately 2 feet wide and 1 foot deep for each plant. Mix the removed soil with a generous amount of well-rotted manure or compost. This organic matter improves both soil structure and fertility, giving your rhubarb the nutrient-rich foundation it needs.

Rhubarb prefers a slightly acidic to neutral pH, ideally between 6.0 and 6.8. If your soil tends toward alkalinity, consider adding amendments to the planting mix to lower the pH slightly.

You can also incorporate a cup of balanced organic fertilizer into each planting hole to give new crowns an extra boost. Just make sure the fertilizer doesn’t come into direct contact with the crown.

Plant at the Correct Depth

One of the most common mistakes gardeners make with rhubarb is planting the crowns at the wrong depth. This seemingly small detail can dramatically affect how well your plants establish and the thickness of the stalks they produce.

When planting rhubarb crowns, position them so the buds are 1-2 inches below the soil surface. Planting too deeply can cause the crown to rot, while planting too shallowly leaves it vulnerable to drying out and temperature fluctuations.

Make sure the buds are pointing upward when you place the crown in the hole. Then backfill with your amended soil, firming it gently around the crown. Water thoroughly after planting to settle the soil and eliminate air pockets.

If you’re transplanting established rhubarb, try to dig up as much of the root system as possible. Rhubarb has substantial roots that support those thick stalks, and preserving them during transplanting helps the plant recover quickly.

Practice Patience in the First Year

This might be the hardest tip to follow, but it’s perhaps the most important for developing great rhubarb stalks: resist the urge to harvest during the plant’s first year in the ground.

During this establishment period, rhubarb needs all its energy to develop a strong root system. Harvesting too early forces the plant to divide its resources between root development and stalk production, resulting in weaker growth overall.

For the first year, allow all stalks to grow without harvesting any. I know it’s tempting, especially when those ruby stalks start emerging, but your patience will be rewarded with substantially thicker stalks in future seasons.

In the second year, you can harvest lightly, taking just a few stalks from each plant and leaving the majority to continue strengthening the root system. By the third year, your rhubarb should be well-established and ready for normal harvesting, which is when you’ll really start to see those thick, juicy stalks.

Feed Regularly

If you want truly impressive rhubarb stalks, regular feeding is essential. These heavy feeders quickly deplete the nutrients in their surrounding soil, leading to thinner stalks if not replenished.

In early spring, before growth begins, apply a layer of well-rotted manure or compost around each plant, keeping it a few inches away from the crown. This slow-release organic matter feeds the plant throughout the growing season.

Also, give rhubarb plants a boost with a balanced organic fertilizer in early spring and again after the first harvest. This additional feeding helps support the development of those thick second-flush stalks later in the season.

If your plants are showing signs of nutrient deficiency (such as yellowing leaves or thin stalks), a side dressing of compost tea can give them a quick boost. Just steep some compost in water for a few days, strain, and use the liquid to water your plants.

Mulch Well

A thick layer of mulch around your rhubarb plants serves multiple purposes, all of which contribute to developing those coveted thick stalks.

Mulch helps retain soil moisture, reducing stress on plants during dry periods. It also suppresses weeds that would otherwise compete for nutrients and water. As organic mulches break down, they add valuable nutrients to the soil, gradually feeding your rhubarb plants.

In colder climates, adding extra mulch in late fall after the ground freezes helps protect the crown from extreme temperature fluctuations. This winter protection ensures the plants emerge strong in spring.

Water Consistently

Consistent moisture is key to developing thick rhubarb stalks. While established plants have some drought tolerance, irregular watering leads to stress that results in thinner, tougher stalks.

Aim to provide your rhubarb plants with 1-2 inches of water per week, either from rainfall or irrigation. During hot, dry periods, you may need to water more frequently to maintain consistent soil moisture.

Drip irrigation or soaker hoses work particularly well for rhubarb, as they deliver water directly to the soil without wetting the foliage. This reduces the risk of fungal issues while ensuring the deep root system gets adequate moisture.

Divide Regularly

Over time, even the healthiest rhubarb plants become crowded and produce increasingly thinner stalks. Dividing your plants every few years rejuvenates them and stimulates the production of thick new stalks.

The best time to divide rhubarb is in early spring just as the new growth begins to emerge, or in fall after the plants have gone dormant. Carefully dig up the entire crown and use a sharp knife or spade to cut it into sections, ensuring each division has at least one or two healthy buds and a portion of the root system.

Replant the divisions following the same guidelines as for new plants, and water them thoroughly to help them establish. After division, treat your rhubarb as you would newly planted crowns. Avoid harvesting in the first year to allow the plants to re-establish their root systems.

Remove Flower Stalks

When rhubarb plants send up tall, central flower stalks, they divert energy away from producing the thick leaf stalks you’re trying to grow. Removing these flower stalks as soon as they appear redirects that energy back where you want it.

You’ll recognize flower stalks by their distinctive appearance. They emerge from the center of the plant and grow rapidly, with a tight cluster of flower buds at the top. Cut or snap these off at the base as soon as you spot them.

Some varieties are more prone to flowering than others, especially during hot or stressful conditions. Older plants also tend to flower more readily than younger ones. Regular division helps reduce flowering, as does consistent watering and feeding.

Practice Proper Harvesting

How you harvest your rhubarb can significantly impact the thickness of future stalks. Using the right technique not only produces better stalks but also protects the crown from damage.

Always harvest the thickest, most mature stalks first, allowing younger, thinner ones to continue developing. This selective harvesting encourages the plant to produce more substantial stalks over time.

Avoid removing more than one-third to one-half of a plant’s stalks in any single harvest. Leaving sufficient foliage ensures the plant can photosynthesize effectively and continue producing healthy new growth.

Stop harvesting by mid-summer (usually late June or early July) to allow your plants time to store energy for the following year’s growth. This restraint pays off with noticeably thicker stalks in the next spring harvest.

Control Pests and Diseases

Healthy plants produce the thickest stalks, so staying vigilant about potential pest and disease issues is essential for impressive rhubarb harvests.

Crown rot is perhaps the most serious disease affecting rhubarb, often caused by poor drainage or overly wet conditions. The first sign is usually wilting foliage, even when the soil is moist. If you notice this, improve drainage immediately and consider relocating plants in severe cases.

Rhubarb weevil, a beetle that bores into stalks, can weaken plants and reduce stalk quality. Look for holes in stalks with associated frass (insect waste) and remove affected stalks promptly. Keeping the area around plants clear of debris helps reduce hiding places for these pests.

Various fungal leaf spots may appear on rhubarb foliage but rarely affect stalk production significantly. Remove severely affected leaves and ensure good air circulation around plants to prevent spread.

One of the most effective ways to prevent pest and disease issues is simply maintaining plant vigor through proper feeding, watering, and division. Strong, healthy plants naturally resist problems better than stressed ones.

Provide Winter Protection

Proper winter care ensures your rhubarb emerges strong in spring, ready to produce thick, vigorous stalks.

After the first hard frost causes the foliage to die back, cut away all leaves and stalks to ground level. This cleanup prevents diseases from overwintering and promotes healthy new growth in spring. Add the leaves to your compost pile only if they’ve been disease-free throughout the season.

Apply a thick layer of mulch over the crowns after the ground freezes (about 4-6 inches of straw, shredded leaves, or compost works well). This insulating layer protects the crowns from freeze-thaw cycles that can damage them and result in weaker spring growth.

Know When to Replace Plants

Even with excellent care, rhubarb plants eventually become less productive over time. Knowing when to start fresh helps maintain consistent production of thick, high-quality stalks.

Most rhubarb plants remain productive for 10-15 years before stalk quality begins to decline noticeably. When your plants consistently produce thin stalks despite proper care and division, it’s likely time to replace them with new stock.

Stagger your rhubarb plantings, adding a few new plants every 5-6 years so you always have some in their prime production years. This succession planting ensures you never experience a gap in harvesting.

Grow in Raised Beds

If you’re starting fresh with rhubarb or looking to relocate existing plants, consider growing them in raised beds for superior stalk development.

Raised beds offer several advantages that contribute to thicker rhubarb stalks. The soil warms earlier in spring, stimulating earlier and stronger growth. Drainage is typically excellent, preventing the crown rot issues that can weaken plants and lead to thin stalks. You also have complete control over the soil quality, allowing you to create the perfect growing medium from the start.

If you do opt for raised beds, make them at least 12 inches deep to accommodate rhubarb’s substantial root system. Position the beds where they’ll receive full morning sun with some afternoon shade in hotter climates.

Let Established Plants Grow

The conventional wisdom of avoiding harvest in the first year is sound, but extending that restraint even longer produces dramatically thicker stalks. Try waiting until the third year before harvesting heavily, taking only a few stalks in the second year.

This extra patience allows the plants to develop massive root systems that can support extremely thick stalk production. It’s a long-term approach, but the difference in stalk quality is remarkable.

Even with established plants, always leave the smaller, thinner stalks to continue developing rather than harvesting everything at once. This selective approach encourages the plant to put energy into substantial growth rather than constantly regenerating after complete harvests.