Colorado’s unpredictable frosts and high altitude mean lemongrass should wait until early June, when nights are reliably warm. Knowing the best time to plant lemon grass in colorado is your first step to growing this fragrant, mosquito-repelling herb successfully in the Centennial State. Lemongrass is a tropical plant, and Colorado’s dry, cool climate presents unique challenges. You need to time your planting perfectly to avoid frost damage and ensure a long enough growing season for a good harvest.
Many gardeners rush to plant in May, only to lose their lemongrass to a late spring snow. The key is patience. Wait until the soil has warmed up consistently and all danger of frost has passed. For most of Colorado, that means targeting early June. Let’s break down exactly how to nail the timing and care for your lemongrass.
Best Time To Plant Lemon Grass In Colorado
The absolute best window for planting lemongrass outdoors in Colorado is from June 1st to June 15th. This timing aligns with the average last frost date for most of the state, which ranges from late May to early June. Planting in early June gives your lemongrass the warm soil and stable nights it needs to establish strong roots before the intense summer heat arrives.
If you live in a warmer microclimate, like the Front Range or Denver metro area, you might push this to late May. But for mountain towns or higher elevations, wait until mid-June. Always check your local frost dates. A simple way to know it’s safe is when nighttime temperatures stay above 50°F (10°C) for a full week.
Why June Is The Sweet Spot
Lemongrass is extremely frost-sensitive. Even a light frost will kill the leaves and damage the roots. Colorado’s spring weather is notoriously fickle. You might have a 70°F day followed by a 30°F night. June offers the most stable warm nights. The soil has also had time to warm up, which is crucial for root development. Cold, wet soil can cause the plant to rot before it even gets started.
Another reason June works is the longer daylight hours. Lemongrass loves full sun and needs at least 6-8 hours of direct sunlight daily. June provides the maximum daylight, helping your plant grow quickly and produce those thick, flavorful stalks. Waiting until July is possible but risky, as the growing season shortens and you may not get a full harvest before fall frosts return.
Understanding Colorado’s Growing Zones
Colorado spans USDA hardiness zones 3 through 7. Most of the populated areas, like Denver, Boulder, and Colorado Springs, are in zones 5b to 6a. These zones have an average last frost date around May 15th to May 25th. However, microclimates vary greatly. A garden in a sheltered south-facing spot will warm up faster than one in a windy, north-facing location. Always use your specific zip code to check your local frost dates. The Old Farmer’s Almanac website is a reliable resource.
For gardeners in zone 4 or lower, like in the mountains, the growing season is even shorter. You’ll need to start lemongrass indoors 6-8 weeks before your last frost date and transplant it out in late June or early July. In these colder zones, consider growing lemongrass in a container that you can move indoors during cold snaps.
How To Start Lemongrass Indoors For A Head Start
Starting lemongrass indoors is the smartest strategy for Colorado gardeners. It gives your plants a 6-8 week head start before they go outside. This is especially important because our growing season is relatively short. Begin seeds or starter stalks indoors 8-10 weeks before your planned outdoor planting date. For a June 1st transplant, start indoors around late March or early April.
Use a seed starting mix and small pots or seed trays. Lemongrass seeds are tiny, so just press them lightly into the soil. Keep the soil consistently moist but not waterlogged. Place the trays in a warm location, around 70-75°F. A heat mat can speed up germination. Provide bright light, either from a sunny south-facing window or grow lights. Seedlings should emerge in 7-14 days.
Using Store-Bought Stalks
An easier method is to root store-bought lemongrass stalks. Look for fresh stalks with the base still intact and some roots visible. Place the base of the stalk in a glass of water, with the cut end submerged. Change the water every few days. Within 1-2 weeks, you’ll see roots and new growth. Once the roots are about an inch long, plant the stalk in a pot with potting soil. Keep it indoors until it’s time to transplant outside.
This method is faster than seeds and gives you a more mature plant. Just make sure the stalks are organic, as non-organic ones may have been treated to prevent sprouting. You can find organic lemongrass at many grocery stores or Asian markets. This is a great way to get a head start without waiting for seeds to germinate.
Preparing Your Colorado Garden For Lemongrass
Lemongrass thrives in well-draining soil rich in organic matter. Colorado’s native soil is often heavy clay or sandy, neither of which is ideal. Before planting, amend your soil with compost or aged manure. Work it in to a depth of 8-10 inches. This improves drainage and adds nutrients. Lemongrass also prefers a slightly acidic to neutral pH, around 6.0 to 7.0. You can test your soil with a simple kit from a garden center.
Choose a location that gets full sun. Lemongrass needs at least 6-8 hours of direct sunlight daily. In Colorado’s high altitude, the sun is intense, so some afternoon shade can be beneficial in very hot areas. However, too much shade will result in leggy, weak growth. Also, protect your plants from strong winds, which can dry them out quickly. A spot near a south-facing wall or fence is ideal.
Spacing And Planting Depth
Space lemongrass plants 18-24 inches apart. They can grow quite large, up to 3-4 feet tall and wide. Proper spacing ensures good air circulation, which helps prevent fungal diseases. When planting, set the root ball at the same depth it was growing in the pot. Do not bury the stem deeper, as this can cause rot. Water thoroughly after planting to settle the soil around the roots.
If you’re planting in containers, choose a pot that is at least 12 inches in diameter and has drainage holes. Use a high-quality potting mix. Container-grown lemongrass will need more frequent watering than in-ground plants. You can also move containers indoors when frost threatens, extending your growing season significantly.
Caring For Lemongrass Through Colorado’s Summer
Once planted, lemongrass needs consistent moisture. Water deeply once or twice a week, depending on rainfall and temperature. Colorado’s dry air and intense sun can dry out soil quickly. Check the soil moisture by sticking your finger an inch into the soil. If it feels dry, it’s time to water. Avoid overhead watering, which can lead to leaf diseases. Water at the base of the plant instead.
Fertilize lemongrass every 4-6 weeks during the growing season. Use a balanced, water-soluble fertilizer or a slow-release granular fertilizer. Lemongrass is a heavy feeder, especially when grown in containers. A fertilizer high in nitrogen will promote lush leaf growth. Stop fertilizing by late August to allow the plant to harden off before fall.
Mulching For Moisture And Warmth
Apply a 2-3 inch layer of organic mulch around the base of your lemongrass. Mulch helps retain soil moisture, regulates soil temperature, and suppresses weeds. In Colorado, where the sun is intense and the air is dry, mulch is essential. Use straw, wood chips, or shredded leaves. Keep the mulch a few inches away from the stems to prevent rot.
Mulch also helps keep the soil warm during cool nights. This is especially important in early June when temperatures can still dip. A layer of mulch can make a difference of several degrees, protecting your plants from light frosts. Replenish the mulch as needed throughout the summer.
Harvesting Lemongrass In Colorado
You can start harvesting lemongrass once the stalks are about 12-18 inches tall and at least 1/2 inch thick at the base. This usually happens 3-4 months after planting. For a June planting, expect your first harvest in late August or early September. Harvest by cutting the stalks at ground level with a sharp knife or pruning shears. Leave at least a few stalks on each plant to continue growing.
Lemongrass is best used fresh, but you can also freeze or dry it. To freeze, chop the stalks into small pieces and store them in a freezer bag. To dry, hang the stalks upside down in a warm, dry place for a week or two. Dried lemongrass can be stored in an airtight container for months. Use it in teas, soups, curries, and marinades.
Extending The Harvest Into Fall
Colorado’s first frost typically arrives in late September or early October. To extend your harvest, cover your lemongrass with a frost cloth or row cover when frost is predicted. You can also dig up the entire plant and bring it indoors. Pot it up and place it in a sunny window. It will continue to grow through the winter, providing fresh lemongrass year-round.
Another option is to take cuttings from your outdoor plants before frost. Root them in water and pot them up. This gives you a fresh start for next year. Overwintering lemongrass indoors is easy. Just reduce watering and stop fertilizing during the winter months. It will go dormant but should bounce back in spring.
Common Problems Growing Lemongrass In Colorado
The most common issue is frost damage. Even a light frost can turn leaves brown and mushy. Always watch the weather forecast and be ready to cover your plants. Another problem is dry, brittle leaves caused by low humidity and intense sun. Regular watering and mulching help. Spider mites can also be a problem in hot, dry conditions. Spray plants with a strong stream of water to dislodge them.
Root rot is a risk if the soil is too heavy or poorly drained. Amend your soil with compost to improve drainage. If you see yellowing leaves or stunted growth, check the roots. Healthy roots are white and firm. Rotten roots are brown and mushy. If root rot is present, remove the affected plant and improve drainage before replanting.
Pest Control Tips
Aphids and mealybugs can sometimes attack lemongrass. These pests are usually easy to control with insecticidal soap or neem oil. Apply in the early morning or late evening to avoid burning the leaves in the intense sun. Beneficial insects like ladybugs and lacewings also help keep pest populations in check. Avoid using broad-spectrum pesticides that kill beneficial insects.
Slugs and snails are less common in Colorado’s dry climate but can be a problem in irrigated gardens. Hand-pick them at night or use diatomaceous earth around the base of the plants. Keep the area around your lemongrass free of debris where pests can hide. Good garden hygiene goes a long way in preventing problems.
Frequently Asked Questions
Can I plant lemongrass in Colorado in July?
Yes, you can plant lemongrass in July, but it’s not ideal. The plant will have a shorter growing season and may not reach full size before frost. If you plant in July, choose a fast-growing variety and provide extra care. Consider starting with larger transplants or rooted stalks to speed up growth.
Does lemongrass come back every year in Colorado?
Lemongrass is a perennial in tropical climates, but it is not winter-hardy in Colorado. It will not survive the cold winters outdoors. You must treat it as an annual or overwinter it indoors. Dig up the plant before the first frost, pot it, and keep it in a sunny indoor spot until spring.
How do I protect lemongrass from Colorado frost?
Cover your lemongrass with a frost cloth, blanket, or row cover when frost is predicted. Use stakes to keep the cover from touching the leaves. For container plants, move them indoors or into a garage. Water the soil well before a frost, as moist soil retains heat better than dry soil.
What is the best variety of lemongrass for Colorado?
East Indian lemongrass (Cymbopogon flexuosus) is the most common variety for culinary use. It grows well in containers and is more tolerant of cooler conditions than West Indian lemongrass. Look for varieties labeled as “hardy” or “cold-tolerant” for best results in Colorado.
Can I grow lemongrass from seeds in Colorado?
Yes, but start seeds indoors 8-10 weeks before your last frost date. Lemongrass seeds are slow to germinate and need warmth. Use a heat mat and keep the soil temperature around 70-75°F. Transplant seedlings outdoors after all frost danger has passed and the soil is warm.
Growing lemongrass in Colorado is absolutely possible with the right timing and care. By planting in early June, starting indoors, and protecting your plants from frost, you can enjoy fresh lemongrass all summer. The key is patience and preparation. With these tips, you’ll have a thriving patch of this aromatic herb in no time. Remember to water consistently, mulch well, and harvest regularly for the best results. Happy gardening.