Rhubarb plants establish best when set out in early spring, while the soil is still cool. Knowing exactly when to plant rhubarb plants can mean the difference between a bumper crop and a disappointing patch. This guide covers everything you need for perfect timing.
When To Plant Rhubarb Plants
Early spring is the ideal window for planting rhubarb. Aim for a period when the ground is workable but not waterlogged. This usually falls between late March and mid-April in most temperate climates.
Planting too late in spring can stress the crowns. The plants need that cool period to establish roots before the heat arrives. If you miss the spring window, early autumn is a secondary option.
Understanding Rhubarb Growth Cycles
Rhubarb is a cold-hardy perennial. It thrives in regions where the ground freezes in winter. The plant requires a dormancy period of cold temperatures to produce strong stalks the following year.
When you set crowns into cool soil, they wake up slowly. This gradual start encourages deep root growth. Strong roots lead to thicker, more tender stalks.
Why Cool Soil Matters
Soil temperature between 40°F and 50°F (4°C to 10°C) is perfect. If the soil is warmer than 60°F (15°C), the crowns may rot or grow leggy. Cool soil reduces transplant shock.
Check your local frost dates. Plant about two weeks before the last expected frost. This timing gives the roots a head start.
Regional Timing Guide
Your exact planting date depends on your climate zone. Here is a breakdown by region.
Northern Climates (Zones 3-5)
- Plant as soon as the soil thaws, usually early April
- Snow melt is a good indicator the ground is ready
- Do not wait for the soil to dry completely
- Late March to mid-April is the sweet spot
Moderate Climates (Zones 6-7)
- Plant in early March to early April
- Soil warms faster here, so monitor closely
- Avoid planting after mid-April
- Consider a light mulch to keep soil cool
Southern Climates (Zones 8-9)
- Plant in late winter, January to February
- Rhubarb struggles in hot summers
- Choose heat-tolerant varieties like ‘Victoria’
- Provide afternoon shade if possible
Step-By-Step Planting Process
Follow these steps for successful planting. Each step matters for long-term health.
- Choose the right site. Full sun is best, but partial shade works in warm areas. Good drainage is critical.
- Prepare the soil. Dig in plenty of compost or aged manure. Rhubarb is a heavy feeder.
- Dig a wide hole. Make it about 2 feet across and 1 foot deep. Space plants 3 to 4 feet apart.
- Set the crown. Place the crown so the buds sit 1 to 2 inches below the soil surface. Do not bury too deep.
- Backfill gently. Firm the soil around the crown. Water thoroughly after planting.
- Mulch lightly. Use straw or shredded leaves to retain moisture and suppress weeds.
Common Planting Mistakes
Many gardeners make these errors. Avoid them for better results.
- Planting too deep: Crowns rot when buried more than 2 inches
- Planting too shallow: Buds dry out or freeze
- Planting in soggy soil: Rhubarb hates wet feet
- Planting in midsummer: Heat stress kills young plants
- Harvesting the first year: Let the plant establish
Preparing Your Rhubarb Crowns
Bare-root crowns are common for planting. They need some prep before going into the ground.
Soak the crowns in water for 1 to 2 hours before planting. This rehydrates the roots. Trim any broken or mushy roots with clean scissors.
If you have potted rhubarb, gently loosen the root ball. Tease out circling roots. This encourages outward growth.
Soil Preparation Tips
Rhubarb prefers a slightly acidic soil pH between 5.5 and 6.5. Test your soil before planting. Add lime if the pH is too low.
Work in a balanced fertilizer like 10-10-10 at planting time. Avoid high-nitrogen fertilizers. They produce leafy growth but weak stalks.
Improving Drainage
If your soil is heavy clay, raise the planting bed. A 6-inch raised bed works well. Mix in sand or perlite to improve drainage.
Alternatively, plant rhubarb in large containers. Use a 20-gallon pot with drainage holes. This gives you control over soil conditions.
Aftercare For New Plants
Once your rhubarb is in the ground, care is simple. Water deeply once a week if rain is scarce. Do not let the soil dry out completely.
Remove any flower stalks that appear in the first year. Flowering diverts energy from root and stalk development. Snip them at the base.
Apply a layer of compost around the plants each spring. This replenishes nutrients. Avoid piling mulch directly against the crowns.
When To Expect First Harvest
Do not harvest any stalks the first year. Let the plant build its root system. You can take a few stalks in the second year.
By the third year, you can harvest freely. Pick stalks that are 12 to 18 inches long. Twist and pull, do not cut.
Fall Planting Considerations
Autumn planting is possible but riskier. The window is 6 to 8 weeks before the first hard frost. This gives roots time to settle.
Plant in late September or early October for most zones. Water well until the ground freezes. Mulch heavily to protect against heaving.
Fall-planted rhubarb may be slower to establish. Spring planting is generally more reliable for beginners.
Container Planting Timing
If you grow rhubarb in pots, you have more flexibility. You can plant earlier in spring because the soil warms faster. But you must protect from late frosts.
Move containers to a sheltered spot if a hard freeze threatens. Potted rhubarb also needs more frequent watering than in-ground plants.
Frequently Asked Questions
Q: Can I plant rhubarb in summer?
A: It is not recommended. Summer heat stresses new plants. Wait for early spring or early autumn.
Q: How deep should I plant rhubarb crowns?
A: Set the crown so buds are 1 to 2 inches below the soil surface. Deeper planting causes rot.
Q: What is the best time to transplant rhubarb?
A: Early spring or early autumn. Divide and replant when the plant is dormant.
Q: Do I need to fertilize rhubarb at planting?
A: Yes, mix in compost or a balanced fertilizer. Avoid high-nitrogen formulas.
Q: How long does rhubarb take to grow from seed?
A: Seeds take 2 to 3 years to produce harvestable stalks. Crowns are faster and more reliable.
Final Timing Tips
Watch the weather, not just the calendar. A late snow or unexpected warm spell can shift your planting window. Be flexible.
If you recieve bare-root crowns by mail, plant them within a few days. Store them in a cool, dark place if you must wait. Keep the roots moist but not wet.
Rhubarb is a long-term investment. A well-timed planting gives you years of harvests. Take the time to do it right.
Remember that rhubarb plants can live for 10 to 15 years. The first few weeks after planting set the stage. Give them a strong start.
One final note: do not be afraid to ask local gardeners. They know the microclimate in your area. Their advice on when to plant rhubarb plants can be invaluable.