How to Grow Rhubarb from Seed

Rhubarb is a wonderfully versatile and hardy perennial plant, cherished for its tart, brightly colored stems that work beautifully in both sweet and savory dishes. Whether it’s showcased in a classic strawberry-rhubarb pie or used to add depth to a sauce, rhubarb brings a unique flavor and nutrition boost to the table. Most gardeners opt for planting crowns or divisions, which offer a head start in the garden, but growing rhubarb from seed can be both a rewarding and economical choice. The process requires patience, as rhubarb grown from seed takes time to mature, but it also opens the door to greater genetic diversity and a stronger sense of connection to your plants.

In this comprehensive guide, you’ll discover exactly how to grow rhubarb from seed—from understanding the plant’s needs and picking the right seeds, to nurturing seedlings and maximizing your eventual harvest. Whether you’re an eager new gardener or an experienced green thumb, following these steps will help ensure your rhubarb plants thrive for years to come.

Understanding Rhubarb and Its Growth Requirements

Before you plant your first seed, it’s important to understand what makes rhubarb thrive. Rhubarb (Rheum rhabarbarum) is a cool-climate perennial that flourishes in growing zones 3 through 8. Known for its chunky, vibrant stalks and oversized leaves, rhubarb is remarkably resilient to cold weather and can survive even under light snow cover. However, it is a long-lived perennial that needs several years to reach full maturity when started from seed—a key factor to consider if you’re hoping for an immediate harvest.

The life cycle of rhubarb is marked by periods of active growth in the spring and summer, followed by dormancy in winter. Optimal growth relies on nutrient-rich, well-drained soil, plenty of sunlight—at least six hours per day—and consistent watering. These elements combine to create the robust, healthy plants that will reward your patience.

Why Grow Rhubarb from Seed?

Many gardeners may ask: Why start rhubarb from seed when crowns are readily available? The answer lies in the benefits of cost-effectiveness and variety. Growing rhubarb from seed can be much less expensive, especially if you’re planting a larger patch. Additionally, seeds open the possibility of greater genetic diversity, which can help plants adapt to local conditions and resist pests or diseases. Seed-grown rhubarb also allows you to experiment with different varieties, each with unique flavors and growth habits, making the gardening journey even more satisfying.

Selecting the Right Rhubarb Seeds

Success in growing rhubarb starts with selecting the right seeds. Choose reliable varieties commonly grown from seed, such as ‘Victoria’ or ‘Glaskins Perpetual’—both of which are known for their vigor and tender stalks. When you purchase seeds, look for reputable suppliers who specialize in heirloom or high-quality garden seeds to increase your chances of strong, healthy plants.

Carefully read the seed packet for important details like germination rate, recommended planting window, and notes on the cultivar’s characteristics. This information will help you coordinate planting and ensure that you provide the best possible environment for each seed to sprout.

Preparing for Planting

Proper preparation is a key factor in the success of rhubarb germination. For most gardeners, rhubarb seeds should be started indoors 6-8 weeks before the last expected frost. This lead time allows seedlings to develop enough to be resilient when moved outside. Because rhubarb seeds have a tough outer coating, it’s helpful to soak the seeds in water for 4–6 hours before planting. For even better results, lightly scarifying the seeds or stratifying them—chilling them in damp paper towels for a week—can boost germination rates by mimicking natural winter conditions.

How to Grow Rhubarb from Seed: Planting Rhubarb Seeds

Step-by-Step Guide to Sowing Seeds Indoors

Start the process by filling clean seed trays or 3-inch pots with a light, well-draining seed-starting mix enriched with organic matter. Plant each seed about half an inch deep, allowing for at least 2 inches of space between seeds or one seed per pot. Lightly press the soil over the seed and mist it with water to ensure good contact.

Keep the trays or pots in a warm spot where the temperature remains between 65–75°F (18–24°C). Indirect sunlight is best; if natural light is insufficient, consider supplementing with grow lights. Maintain consistent moisture by checking the soil every day—damp but not soggy is ideal, as overwatering can lead to rot.

Germination typically occurs in 10–21 days, depending on temperature and seed vigor. Once sprouts appear, continue to provide steady moisture and gentle light to promote healthy seedling development.

Managing Seedlings

After a few weeks, your rhubarb seedlings will begin to develop their second set of true leaves. At this stage, it’s important to thin crowded seedlings by removing the weakest plants, leaving only the strongest in each cell or pot. This prevents competition for light, nutrients, and water, giving each plant the maximum chance for robust growth.

Water seedlings regularly, but don’t allow the growing medium to become waterlogged. When in doubt, test the top inch of soil; if it feels dry, it’s time to water.

Hardening Off Rhubarb Seedlings

Before transplanting seedlings outside, acclimate them gradually to outdoor conditions—a process known as hardening off. Start by placing trays or pots in a shaded, sheltered area outdoors for a couple of hours each day, increasing the time outside and sun exposure over a week to ten days. This helps the seedlings adapt to sunlight, wind, and fluctuating temperatures, reducing the risk of transplant shock.

Transplanting Rhubarb Seedlings to the Garden

Choosing the Ideal Planting Location

Rhubarb requires a location that receives full sun or partial shade, with rich, well-drained soil. Avoid areas prone to standing water, as wet roots can lead to rot. Mature plants can spread widely, so plan for at least 3 to 4 feet between each plant to give them plenty of room to grow.

Preparing the Soil

To create the ideal bed for your rhubarb, work compost or well-rotted manure into the soil before planting. This adds organic nutrients and improves structure and drainage. It’s also wise to check the soil pH; rhubarb thrives best when the pH is between 6.0 and 6.8. If necessary, adjust the pH with lime (to raise) or sulfur (to lower) to create the optimal environment.

Transplanting Process

On a cool, cloudy day or in the late afternoon, gently remove seedlings from their pots, taking care not to disturb the roots. Dig a hole slightly larger than the seedling’s root ball and set the plant in place so the crown is just at or slightly below soil level. Fill in gently with soil, press lightly, and water thoroughly.

After planting, applying a thin mulch of straw or leaf mold around the plants helps to retain moisture, regulate temperature, and suppress competing weeds. Mulch also shields developing roots from temperature swings and helps your new plants settle in more quickly.

Caring for Growing Rhubarb Plants

Once your rhubarb is planted in the garden, ongoing care is straightforward but critical to robust growth.

Water your rhubarb regularly, especially during dry spells. Aim for about an inch of water per week throughout the growing season, more during periods of excessive heat or drought. A deep soaking is preferable to frequent shallow watering, as this encourages roots to grow deeper.

Fertilize twice each year with a slow-release, organic fertilizer: once in early spring as the shoots emerge and again after harvesting the last stalks. Stick to low-nitrogen feeders to avoid lush leaves at the expense of strong stalks.

Mulching remains important throughout the season. Apply a fresh layer of organic mulch around the base of the plants in late spring to help retain soil moisture and keep weeds in check. Regularly inspect the mulch and top up as needed.

Common Pests and Diseases

While rhubarb is generally resistant to many common pests and diseases, it is not immune. Watch for slugs and snails, especially after rain, as well as aphids, which sometimes cluster around new shoots. These can be picked off by hand or managed with organic treatments like neem oil or insecticidal soap.

To prevent root rot or crown rot, the most important step is proper drainage. Never allow rhubarb to sit in soggy soil, and avoid over-watering. Remove any yellow or rotting leaves promptly to halt the spread of disease.

Maintaining Rhubarb Plants Over Time

Rhubarb is a perennial, meaning it will grow back year after year when properly maintained. In autumn, after the first hard frost, cut back the stems and leaves to a few inches above ground. Take care not to disturb the crown.

To help your plant survive winter, apply a thick layer of mulch such as straw, compost, or shredded leaves over the root zone. This insulates the crown and prevents rapid freeze-thaw cycles, which can damage the plant.

Every four to five years, divide established rhubarb crowns in early spring or fall. This not only rejuvenates older plants but also provides you with new starts to expand your patch or share with other gardeners.

Harvesting Rhubarb

Patience is key with rhubarb grown from seed. Avoid harvesting any stalks until the second year—third is even better—as the plants need time to establish a strong root system.

When harvest time comes, select thick, firm stalks about 12–18 inches long. Instead of cutting, grasp the base of the stalk near the ground and gently twist and pull it free. This minimizes the risk of disease entering through open cuts. Always leave at least a third of the stalks intact, as these are vital for ongoing growth.

It’s crucial never to eat rhubarb leaves, as they contain oxalic acid and are toxic to both humans and pets. Compost the leaves or dispose of them safely after harvesting.

Maximizing Yields

Encourage higher production by regular feeding and by removing flower stalks as soon as they appear. Flowering signals the plant to direct energy toward seed production rather than stem growth. Harvest regularly, but never take too many stems at once, to keep the plant healthy and productive throughout the season.

Troubleshooting Rhubarb Growth Issues

Even with the best care, you may face occasional challenges. Slow growth or weak plants often point to nutrient-poor soil, lack of sunlight, or excessive competition from weeds. Adjusting your watering habits, adding compost, or moving poorly performing plants to a sunnier location can often resolve these issues.

Yellowing leaves could indicate overwatering, poor drainage, or pest infestations. Check soil conditions and inspect for unwanted insects. Address problems quickly to boost your rhubarb’s vigor and prevent losses in the following season.

Conclusion

Growing rhubarb from seed is a test of patience, but the results are well worth the effort. Not only do you enjoy significant cost savings and a greater selection of varieties, but you also experience the unique satisfaction of raising healthy, productive plants entirely from scratch.

By following the best practices outlined in this guide—understanding your plant’s needs, sowing and transplanting at the optimal times, and caring for your crops throughout the seasons—you now know how to grow rhubarb from seed and can look forward to enjoying a bountiful harvest in your garden for years to come. Embrace the journey and let your rhubarb patch become a symbol of both your persistence and gardening success.