How To Grow Thick Rhubarb Stalks

If you want to know how to grow thick rhubarb stalks, you’re in the right place. Getting those robust, juicy stems is a matter of giving your plant exactly what it needs. Thick stalks mean a better harvest for pies, jams, and sauces. Let’s look at the simple steps to make your rhubarb plants thrive.

This goal is all about fundamentals. Thick stalks come from a deeply established, healthy plant. You can’t force it in a single season. Instead, you build the conditions for success over time. Focus on these core areas, and your rhubarb will reward you.

Start with the Right Variety and Plant

Your first decision is crucial. Some rhubarb varieties are simply bred for thicker stalks. Do a little research before you buy.

‘Victoria’ is a common, reliable variety, but stalks can be thinner.
‘Canada Red’ and ‘Crimson Red’ are known for their thick, deeply colored stems.
‘German Wine’ is a champ for both thickness and flavor.

Always start with a dormant crown or a division from a healthy plant. Growing from seed takes years longer and results can be inconsistent. A good nursery crown gives you a multi-year head start.

The Non-Negotiable: Sun, Soil, and Space

Rhubarb is a heavy feeder that loves sunlight. Getting these three elements wrong is the main reason for thin, spindly stalks.

Full Sun: Plant in a spot that gets at least 6-8 hours of direct sun daily. More sun means more energy for thick growth.
Soil is Everything: Rhubarb needs deep, fertile, and well-draining soil. It hates wet, clay-heavy feet. Aim for a loamy soil rich in organic matter.
Give It Room: Each plant needs space. Plant crowns 3-4 feet apart. Crowding leads to competition for nutrients and air, resulting in weaker stalks.

Preparing the Perfect Planting Hole

Don’t just plop the crown in the ground. A little extra work here pays off for a decade.

Dig a hole at least 2 feet wide and 1.5 feet deep.
Mix the excavated soil with several shovelfuls of well-rotted compost or aged manure. Add a handful of bone meal for strong root development.
Place the crown so the buds are just 1-2 inches below the soil surface.
Backfill with your enriched soil, water deeply, and mulch with straw or leaves.

Feeding for Strength and Thickness

Rhubarb’s appetite is huge. To produce those massive stalks, it needs constant nutrition.

Early Spring: As growth begins, side-dress with a balanced organic fertilizer or a generous layer of compost.
After Harvest: This is the most important feeding. In late June or early July, give your plant a major nutrient boost. Use composted manure and a fertilizer higher in nitrogen to help the plant recover and build energy for next year.
Late Fall: After the plant dies back, add a top dressing of compost. This breaks down over winter, feeding the soil.

Never use chemical fertilizers high in nitrogen mid-season; it can lead to lots of leafy growth at the expense of your stalks.

The Art of Watering and Mulching

Consistent moisture is key, but “consistent” doesn’t mean “soggy.”

Rhubarb needs about 1 inch of water per week, more during hot, dry spells. Deep, infrequent watering is better than daily sprinkles. It encourages roots to grow down deep, which supports thicker top growth. A soaker hose is ideal.

Mulch is your best friend. A 2-3 inch layer of straw, shredded leaves, or compost does wonders:

Retains soil moisture.
Suppresses weeds that compete for food.
Regulates soil temperature.
Breaks down to add organic matter.

Just keep the mulch a few inches away from the crown itself to prevent rot.

Smart Harvesting for Future Growth

How you harvest directly impacts next year’s stalk thickness. Patience is vital.

Wait: Do not harvest any stalks in the plant’s first year. In the second year, take just a few. This allows the plant to build its energy reserves.
Technique: Never cut the stalks. Instead, grasp a stalk near the base, twist gently, and pull it sideways away from the crown. This gives a clean break.
Stop Early: Always stop harvesting by mid-summer (around July 4th is a good rule). The plant needs its leaves to photosynthesize and rebuild for next season.
Never Over-Harvest: Never take more than one-third to one-half of the stalks from a mature plant at one time. And always leave at least 5-7 stalks growing.

Essential Annual Maintenance

A few yearly tasks keep your rhubarb in peak condition.

Remove Seed Stalks: If a tall flower stalk appears from the center, cut it off immediately. Letting the plant go to seed wastes a massive amount of energy that should go into the edible stalks.
Divide When Needed: Every 5-8 years, plants become overcrowded and stalks get thinner. The best time to divide is in early spring as the plant emerges. Dig up the whole crown, split it into sections with at least 2-3 buds each, and replant.
Keep it Clean: In late fall, after frost blackens the leaves, remove all plant debris from around the crown to discourage pests and disease.

Troubleshooting Thin Stalks

If your stalks are still thin, run through this checklist.

Too Old/Needs Dividing: Is the plant a giant, dense clump? It’s likely time to divide it.
Hungry/Thirsty: Are you feeding and watering enough, especially after harvest?
Over-Harvested: Did you harvest too late or take to many stalks last season?
Not Enough Sun: Have nearby trees or shrubs grown and created more shade?
Poor Soil: The soil may be depleted. A soil test can reveal nutrient deficiencies.

FAQ: Your Rhubarb Thickness Questions Answered

What is the best fertilizer for thick rhubarb stalks?

Well-rotted manure or compost is the absolute best. It feeds the plant and improves soil structure. In early spring, a balanced organic fertilizer (like a 5-5-5) works well. Avoid high-nitrogen chemical fertilizers.

Does Epsom salt help rhubarb grow thicker?

Epsom salt provides magnesium, which can be beneficial if your soil is deficient. It’s not a magic bullet for thickness. A soil test is the best way to know if you need it. Otherwise, focus on compost and consistent care.

How long does it take for a rhubarb plant to produce thick stalks?

You need patience. A new crown might produce decent stalks by its third year. For truly thick, harvest-worthy stalks, you’re looking at a plant that’s 4-5 years old and has been cared for properly. The wait is worth it, as a healthy plant can produce for 10-15 years or more.

Should I cut or pull rhubarb stalks?

Always pull, never cut. Twisting and pulling the stalk away from the crown removes the entire stem base. If you cut it, the leftover stump can rot and become an entry point for disease into the crown.

Why are my rhubarb stalks thin and spindly?

The most common reasons are: lack of sunlight, overcrowded plants that need dividing, insufficient nutrients (especially after harvest), or harvesting to aggressively or for too long during the season. Review the care steps above to diagnose your plant.

Growing thick rhubarb stalks is a testiment to good gardening. It’s about building soil health, practicing patience, and providing consistent care season after season. Start with a good variety, give it sun and rich soil, feed it generously, and harvest with restraint. Follow these steps, and you’ll be rewarded with a robust harvest of thick, flavorful stalks for many springs to come. There’s nothing quite like the satisfaction of pulling your first truly substantial stem from a plant you nurtured yourself.