Minnesota’s short growing season forces gardeners to start rhubarb as soon as the ground thaws. Knowing the best time to plant rhubarb in minnesota is the first step to a bumper crop of tart stalks.
Rhubarb is a tough, cold-hardy perennial that thrives in our chilly climate. Get the timing right, and you’ll be harvesting for decades. Let’s break down exactly when and how to plant it.
Understanding Minnesota’s Growing Zones
Minnesota spans USDA hardiness zones 3a in the north to 4b in the south. This affects your planting window. The ground thaws later up north, so you’ll need to adjust your schedule.
In general, the soil is workable from mid-April in the south to early May in the north. Rhubarb crowns or roots need to go in as soon as the soil is thawed and not waterlogged.
Zone 3A And 3B Planting Window
If you live in northern Minnesota, wait until late April or early May. The ground might still be frozen in early April. Check your local frost dates.
Plant when the soil temperature reaches about 40°F. You can use a soil thermometer to be sure. Rhubarb is frost-tolerant, so a late spring freeze won’t kill it.
Zone 4A And 4B Planting Window
In southern Minnesota, you can start planting in mid-April. The soil warms up faster here. Aim for when the ground is dry enough to crumble in your hand.
If you plant too early into mud, the roots can rot. Wait a week after the snow melts if the ground is still soggy.
Best Time To Plant Rhubarb In Minnesota
The absolute best window is from early April to mid-May, depending on your location. This gives the roots time to establish before the summer heat arrives.
Planting in fall is not recommended in Minnesota. The winter cold can heave young plants out of the ground. Spring planting gives them a full season to grow strong.
If you miss the spring window, you can plant in late August or early September. But you’ll need to mulch heavily before winter. Spring is still the safest bet.
Why Spring Planting Works Best
Rhubarb needs cool soil to root well. Spring’s cool temps and regular rain help the crown settle in. By summer, the plant is established and can handle heat.
Planting too late in June or July stresses the plant. The heat forces it to focus on survival, not root growth. You’ll get a weaker plant and a smaller harvest next year.
How To Prepare The Soil
Rhubarb likes rich, well-drained soil with a pH between 6.0 and 6.8. Test your soil before planting. Add lime if it’s too acidic.
Choose a sunny spot. Rhubarb needs at least 6 hours of direct sun daily. More sun means stronger stalks. Avoid shady areas near trees or buildings.
Step-By-Step Soil Prep
- Clear the area of weeds and grass. Rhubarb doesn’t compete well.
- Dig a hole 12 inches deep and 18 inches wide.
- Mix in 2 to 3 inches of compost or well-rotted manure.
- Add a handful of balanced fertilizer, like 10-10-10.
- Fill the hole back in with the amended soil.
Good soil prep is key. Rhubarb can live 15 to 20 years, so invest the time now.
Choosing The Right Rhubarb Variety
Not all rhubarb varieties are equal in Minnesota. Some are more cold-hardy and productive. Pick a variety bred for northern climates.
- Canada Red: Sweet, red stalks. Very cold-hardy.
- Victoria: Classic green stalks. Reliable and productive.
- Valentine: Bright red, tender stalks. Good for early harvest.
- Riverside Giant: Huge stalks. Tolerates cold well.
Avoid varieties that need a long, warm growing season. They won’t perform well here.
Where To Buy Rhubarb Crowns
Buy crowns from local nurseries or online seed catalogs. Look for dormant crowns with firm, plump buds. Avoid any that are shriveled or moldy.
You can also start from seed, but it takes a year longer to harvest. Crowns are faster and more reliable for beginners.
Planting Rhubarb Crowns Correctly
Planting depth is critical. Too deep and the crown rots. Too shallow and it dries out. Aim for the crown to sit 1 to 2 inches below the soil surface.
Space plants 3 to 4 feet apart. Rhubarb grows large and needs room for its leaves. Crowded plants produce thinner stalks.
Step-By-Step Planting
- Dig a hole wide enough for the roots to spread out.
- Place the crown in the center with buds facing up.
- Cover with soil so the buds are just barely covered.
- Water thoroughly to settle the soil.
- Add a 2-inch layer of mulch to retain moisture and suppress weeds.
Water weekly if rain is scarce. Keep the soil moist but not soggy for the first month.
Aftercare For New Rhubarb Plants
Don’t harvest any stalks in the first year. Let the plant focus on root growth. You can take a few stalks in the second year, but wait until the third year for a full harvest.
Fertilize in early spring with a balanced fertilizer. Side-dress with compost in mid-summer. Remove flower stalks as soon as they appear to keep energy in the roots.
Winter Protection
Mulch heavily after the ground freezes. Use straw, leaves, or wood chips. This prevents frost heave, which can push crowns out of the soil.
In northern Minnesota, add an extra layer of mulch. Remove it in early spring when the ground starts to thaw.
Common Mistakes To Avoid
Many gardeners make simple errors that hurt their rhubarb. Here’s what to watch for:
- Planting too deep: Crowns rot if buried more than 2 inches.
- Overharvesting: Never take more than one-third of the stalks at once.
- Ignoring weeds: Weeds steal nutrients and water.
- Planting in shade: Stalks will be thin and pale.
- Forgetting to divide: Divide every 5 to 7 years to keep plants productive.
Avoid these, and your rhubarb will thrive for years.
When To Expect Your First Harvest
If you plant in spring, you can harvest lightly in the second year. By the third year, you’ll get a full crop from late May through July.
Stop harvesting by early August. This lets the plant store energy for next year. The leaves will die back in fall, and the plant goes dormant.
Signs Your Rhubarb Is Ready
Stalks should be at least 12 inches long and firm. Pull them gently from the base, twisting slightly. Don’t cut them, as the stub can rot.
Only harvest stalks that are thick and healthy. Thin stalks mean the plant is still young or stressed.
Frequently Asked Questions
Can I Plant Rhubarb In Fall In Minnesota?
It’s risky. Winter cold can heave young plants. Spring planting is much more reliable. If you must plant in fall, do it by mid-September and mulch deeply.
How Late Can I Plant Rhubarb In Minnesota?
You can plant until late May in the south and early June in the north. After that, the heat stresses the plant. Wait until late August if you miss the spring window.
Should I Soak Rhubarb Crowns Before Planting?
Soaking for an hour in lukewarm water can rehydrate dry crowns. But don’t soak for more than a few hours, or they might rot. Plant immediately after soaking.
How Do I Know If My Rhubarb Is Getting Enough Sun?
Healthy stalks are thick and upright. If they lean toward the sun or look spindly, move the plant to a sunnier spot in fall or spring.
Can I Grow Rhubarb In A Container In Minnesota?
Yes, but use a large pot, at least 18 inches wide and deep. Move it to a sheltered spot in winter or wrap the pot in insulation. Container plants need more water and fertilizer.
Final Tips For Success
Rhubarb is one of the easiest perennials to grow in Minnesota. Get the planting time right, and you’ll have a low-maintenance crop for years.
Mulch well, water during dry spells, and divide every 5 years. Your rhubarb will reward you with plenty of stalks for pies, jams, and sauces.
Remember, the best time to plant rhubarb in minnesota is early spring, as soon as the ground is workable. Don’t wait too long, or you’ll miss the window.
Start preparing your soil now, order your crowns, and get ready for a great harvest. Your future self will thank you when you’re enjoying fresh rhubarb in June.
Happy gardening, and don’t forget to share your rhubarb with neighbors. It’s a Minnesota tradition.