Washington’s rainy springs provide ideal moisture for lemon grass planted after the last frost. Finding the best time to plant lemon grass in washington can mean the difference between a thriving patch and a sad, stunted plant. You want fresh stalks for teas and cooking, not a gardening headache.
Lemon grass loves warmth. It hates cold soil and frost. In Washington, your planting window depends on your specific region, from the wet west side to the drier east. This guide walks you through exactly when and how to plant, so you get the best results.
Best Time To Plant Lemon Grass In Washington
The absolute best window is late spring to early summer. Specifically, aim for two to three weeks after your area’s average last frost date. Soil temperature should be consistently above 60°F (15°C).
For most of western Washington, that means mid-May to early June. Eastern Washington, with its later frosts, might push that to late May or even early June. Check your local frost dates online—they vary widely.
Planting too early risks cold damage. Planting too late means less time for growth before fall cool-down. Lemon grass needs about 100 frost-free days to reach a decent size.
Why Timing Matters So Much
Lemon grass is a tropical perennial. It’s not adapted to Washington’s cool springs. If you plant when soil is cold, roots rot. The plant may survive but stay small all season.
Warm soil encourages fast root development. The plant then puts energy into stalks and leaves. You get a fuller, more productive plant that can handle summer heat.
Also, lemon grass planted at the right time is more resilient to pests and diseases. Stressed plants attract problems. Healthy plants shrug them off.
Checking Soil Temperature
Don’t rely on air temperature alone. Soil warms slower. Use a soil thermometer. Insert it four inches deep in the morning. If it reads 60°F or higher for three consecutive days, you’re good.
No thermometer? Watch for weeds. When dandelions and crabgrass start growing actively, soil is warm enough. Also, if nighttime lows stay above 50°F for a week, it’s safe.
In Washington, coastal areas may have cooler soil longer. Inland valleys warm faster. Adjust your timing by a week or two based on your microclimate.
Regional Planting Guides For Washington
Washington is not one climate. The Cascade Mountains split it into two distinct zones. Your planting time shifts depending on which side you live on.
Western Washington (West Of The Cascades)
This includes Seattle, Tacoma, Olympia, and the coast. Winters are mild and wet. Springs are cool and rainy. Summers are moderate.
- Average last frost: March 15 to April 15, depending on location
- Best planting window: May 1 to June 1
- Soil temperature check: Usually ready by mid-May
- Note: Coastal areas near the ocean may need to wait until late May
Western Washington’s long, mild fall helps lemon grass keep growing into October. You can often harvest until the first hard frost in November.
Eastern Washington (East Of The Cascades)
This includes Spokane, Yakima, Wenatchee, and the Columbia Basin. Winters are cold and dry. Springs are short and warm up fast. Summers are hot and dry.
- Average last frost: April 15 to May 15, later in higher elevations
- Best planting window: May 15 to June 15
- Soil temperature check: Usually ready by late May
- Note: Higher elevations like Spokane may need to wait until June
Eastern Washington’s hot summers can stress lemon grass if not watered well. But the warm soil speeds growth. You might get a bigger plant by fall than in the west.
Mountain And High Elevation Areas
Places like Leavenworth, Winthrop, or Mount Rainier area have very short growing seasons. Frost can occur even in June.
- Average last frost: May 15 to June 15
- Best planting window: June 1 to July 1
- Soil temperature check: Often not ready until mid-June
- Note: Consider starting plants indoors or using season extenders
In these areas, lemon grass may not reach full size. But you can still enjoy fresh stalks for tea. Just manage expectations.
How To Plant Lemon Grass Step By Step
Once you’ve picked the right time, follow these steps for success. Lemon grass is forgiving, but proper planting sets you up.
- Choose a sunny spot. Lemon grass needs full sun—at least 6 hours daily. In eastern Washington, some afternoon shade can help in extreme heat.
- Prepare the soil. Loosen soil 12 inches deep. Mix in 2-3 inches of compost. Lemon grass likes rich, well-draining soil.
- Dig holes. Space plants 2-3 feet apart. They grow into large clumps. Dig holes as deep as the root ball and twice as wide.
- Plant carefully. Place the plant at the same depth it was in the pot. Backfill with soil and press gently to remove air pockets.
- Water thoroughly. Give each plant a good soak right after planting. This settles the soil and helps roots make contact.
- Mulch around plants. Apply 2-3 inches of organic mulch like straw or wood chips. This keeps soil moist and warm, and suppresses weeds.
- Water regularly. Keep soil consistently moist but not soggy for the first few weeks. Once established, water deeply once a week.
If you’re planting in containers, use a pot at least 12 inches wide. Lemon grass roots are vigorous. Ensure drainage holes are clear.
Starting Lemon Grass Indoors
For a head start, especially in cooler areas, start lemon grass indoors 6-8 weeks before your last frost. Use seed-starting mix and small pots.
Keep soil warm—around 70°F. A heat mat helps. Provide bright light, either from a sunny window or grow lights. Harden off plants gradually before moving outside.
Indoor-started plants can be transplanted at the same time as store-bought ones. They’ll just be bigger and more established from the start.
Caring For Lemon Grass After Planting
Once planted, lemon grass needs consistent care. Washington’s weather can be unpredictable, so stay attentive.
Watering Needs
Lemon grass likes moisture but not wet feet. In western Washington’s rainy springs, you may not need to water much at first. In eastern Washington’s dry springs, water deeply twice a week.
During summer, water deeply once a week. More often if temperatures exceed 90°F. Check soil moisture by sticking your finger an inch deep. If dry, water.
Container plants dry out faster. Check daily in hot weather. Water until it drains from the bottom.
Fertilizing
Lemon grass is a heavy feeder. Apply a balanced fertilizer (like 10-10-10) once a month during the growing season. Or use a slow-release organic fertilizer at planting time.
Compost tea or fish emulsion works well. Apply every 2-3 weeks for extra growth. Stop fertilizing by late August to let plants harden off for winter.
Pruning And Harvesting
Harvest stalks when they are at least 12 inches tall and about 1/2 inch thick. Cut at ground level with a sharp knife. Leave the main clump intact.
Remove dead or yellowing leaves regularly. This improves air circulation and reduces disease risk. In fall, cut back the plant to about 6 inches tall before frost.
You can harvest continuously from midsummer until frost. The more you cut, the more the plant produces new growth.
Overwintering Lemon Grass In Washington
Lemon grass is not winter-hardy in Washington. It will die if left outside in freezing temperatures. You have two options: bring it indoors or treat it as an annual.
Bringing Plants Indoors
Before the first frost, dig up a clump or move a container indoors. Cut back leaves to 6 inches. Pot in fresh soil if needed.
Place in a bright, cool spot indoors—around 60-65°F is ideal. Water sparingly, just enough to keep soil slightly moist. It will go semi-dormant.
In spring, gradually reintroduce it to outdoor conditions after frost danger passes. This saves you from buying new plants each year.
Treating As An Annual
If you don’t want to overwinter, simply replant each spring. Lemon grass is inexpensive and grows fast. Many gardeners prefer this approach.
You can also take cuttings from your plant in fall. Root them in water indoors, then plant in spring. This gives you free plants.
Common Problems And Solutions
Even with perfect timing, issues can arise. Here are common problems and how to fix them.
- Yellow leaves: Usually overwatering or poor drainage. Let soil dry out between waterings. Improve drainage with sand or perlite.
- Brown leaf tips: Low humidity or underwatering. Mist leaves occasionally. Water more deeply.
- Stunted growth: Cold soil or lack of nutrients. Check soil temperature. Fertilize with a balanced product.
- Pests: Spider mites or aphids. Spray with neem oil or insecticidal soap. Keep plants healthy to resist infestations.
- Root rot: Caused by waterlogged soil. Ensure good drainage. Remove affected parts and repot in fresh soil.
Most problems stem from improper watering or planting too early. Stick to the recommended timing and you’ll avoid many headaches.
Frequently Asked Questions
Can I plant lemon grass in fall in Washington?
No. Fall planting is not recommended. Lemon grass needs warm soil and a long growing season. Fall-planted lemon grass will likely die over winter.
How late can I plant lemon grass in Washington?
You can plant as late as early July, but the plant will be smaller. For best results, plant by June 1 in most areas. Later planting means less harvest time.
Should I start lemon grass from seed or buy plants?
Seeds take longer and need warmth. For Washington’s short season, buying starter plants from a nursery is easier and more reliable. Seeds work if started indoors early.
Does lemon grass need full sun in Washington?
Yes, full sun is best. In eastern Washington’s hot summers, some afternoon shade can help prevent leaf burn. But at least 6 hours of direct sun is ideal.
Can I grow lemon grass in a container in Washington?
Absolutely. Containers warm up faster in spring, so you can plant a bit earlier. Just move the container indoors before frost. This makes overwintering easier.
Final Tips For Success
Timing is everything, but other factors matter too. Choose a variety suited to your area. Common lemon grass (Cymbopogon citratus) works well in Washington.
Mulch heavily to keep roots warm and moist. In western Washington, this also helps with weed control. In eastern Washington, it conserves water.
Don’t be afraid to experiment. If you plant a week early and get lucky with weather, you might get an extra month of growth. Just be ready to protect plants if frost threatens.
Lemon grass is rewarding. It grows fast, smells amazing, and adds flavor to your kitchen. With the right timing and care, you’ll have plenty to share.
Remember, the best time to plant lemon grass in washington is after the last frost when soil is warm. Check your local frost dates, prepare your soil, and plant with confidence. Your taste buds will thank you.
If you follow this guide, you’ll avoid common mistakes. No more sad, yellow plants. No more wasted effort. Just fresh, fragrant lemon grass all season long.
Start planning now. Mark your calendar for mid-May. Gather your supplies. When the time comes, you’ll be ready to plant and enjoy the results.
Happy gardening—and happy cooking with your homegrown lemon grass.