Colorado’s high altitude and cool nights create a short but productive catnip growing window. Finding the best time to plant catnip in Colorado means working with our unique climate, not against it. If you time it right, you’ll have lush plants that drive your cats wild and attract beneficial pollinators to your garden.
Catnip (Nepeta cataria) is a hardy perennial that actually thrives in Colorado’s dry conditions once established. The trick is getting it started at the right moment. Let me walk you through exactly when and how to plant catnip in every part of the state.
Best Time To Plant Catnip In Colorado
The absolute best time to plant catnip in Colorado is in early spring, right after the last frost date. For most Front Range gardeners, that means late April to mid-May. In higher elevations like the mountains, you might need to wait until late May or early June.
Catnip seeds need soil temperatures around 60-70°F to germinate well. Colorado’s spring soil warms up slowly, so don’t rush it. Planting too early when the ground is still cold will just rot your seeds.
Fall planting is also an option for experienced gardeners. Plant seeds or transplants in late August to early September. This gives plants time to establish roots before winter dormancy. But spring planting is more reliable for beginners.
Understanding Colorado’s Growing Zones
Colorado spans USDA hardiness zones 3 through 7. Your exact location changes the planting calendar significantly.
- Denver and Front Range (Zone 5-6): Plant catnip outdoors mid-April to mid-May
- Western Slope (Zone 6-7): Plant late March to late April
- Mountains and high valleys (Zone 3-4): Plant late May to early June
- Eastern Plains (Zone 5): Plant mid-April to early May
Check your specific zone using the USDA map online. Your local county extension office can give you exact frost dates for your area.
Why Spring Planting Works Best
Catnip is a cool-season perennial. It actually prefers temperatures between 55-75°F. Colorado’s spring weather, with its warm days and cool nights, is perfect for germination and early growth.
Spring planting gives your catnip a full growing season to develop strong roots. By summer, when temperatures hit 90°F or higher, established plants can handle the heat. Young seedlings might struggle with intense afternoon sun.
Another benefit: spring-planted catnip often flowers in its first year. That means you get leaves for drying and flowers for your cats to enjoy by late summer.
Step-By-Step Planting Guide For Colorado
Follow these steps to get your catnip off to a strong start in Colorado’s challenging climate.
Step 1: Choose The Right Location
Catnip needs full sun, which means at least 6 hours of direct sunlight daily. In Colorado’s intense sun, some afternoon shade can help prevent leaf scorch, especially in lower elevations.
Pick a spot with well-draining soil. Colorado’s clay soil holds water too long and can cause root rot. If your soil is heavy clay, plant catnip in raised beds or amend with compost and sand.
Catnip spreads aggressively through self-seeding. Consider planting it in a contained area or use pots to keep it from taking over your garden.
Step 2: Prepare The Soil
Catnip isn’t picky about soil fertility, but it needs good drainage. Mix 2-3 inches of compost into the top 6-8 inches of soil. This improves both drainage and nutrient content.
Colorado soil is often alkaline. Catnip prefers slightly acidic to neutral pH (6.0-7.5). You can add sulfur or peat moss to lower pH if needed, but most Colorado soils work fine without adjustment.
Remove rocks and break up large soil clods. Catnip seeds are tiny and need fine soil to make good contact for germination.
Step 3: Plant Seeds Or Transplants
For seeds: Sow seeds directly outdoors after the last frost. Scatter seeds on the soil surface and barely cover them with 1/8 inch of fine soil. Seeds need light to germinate, so don’t bury them deep.
Space seeds about 12-18 inches apart. Thin seedlings to 18-24 inches apart once they have 2-3 true leaves. Catnip plants can grow 2-3 feet tall and wide.
For transplants: Start seeds indoors 6-8 weeks before your last frost date. Use seed-starting mix and keep soil moist but not waterlogged. Transplant outdoors after hardening off for a week.
Transplants give you a head start and are more reliable in short growing seasons. Many Colorado gardeners prefer this method for mountain areas.
Step 4: Water Correctly
Catnip is drought-tolerant once established, but young plants need consistent moisture. Water deeply once or twice a week during the first month.
After establishment, water only when the top 2 inches of soil feel dry. Overwatering is the most common mistake. Colorado’s dry air means less fungal disease, but wet soil still causes root rot.
Use drip irrigation or soaker hoses to keep water off the leaves. This prevents powdery mildew, which can occur in humid conditions.
Step 5: Mulch And Maintain
Apply 2-3 inches of organic mulch around plants. Straw, wood chips, or shredded leaves work well. Mulch conserves moisture, regulates soil temperature, and suppresses weeds.
Fertilize lightly once in early summer with a balanced fertilizer. Too much nitrogen produces lush leaves but fewer flowers. Catnip doesn’t need heavy feeding.
Pinch back growing tips when plants are 6-8 inches tall. This encourages bushier growth and more leaves for harvesting.
Fall Planting Considerations
Fall planting works in Colorado if you time it right. Plant 6-8 weeks before the first expected frost. For most areas, that’s mid-August to mid-September.
Fall-planted catnip needs extra care. Water regularly until the ground freezes. Apply a thick layer of mulch (4-6 inches) after the first hard freeze to protect roots.
The advantage of fall planting is earlier growth next spring. Plants that overwinter well will start growing as soon as soil warms up, giving you a head start on the season.
But fall planting carries risk. A sudden early freeze can kill young plants. Colorado’s unpredictable weather makes spring planting safer for most gardeners.
Growing Catnip Indoors In Colorado
You can grow catnip indoors year-round in Colorado. This is perfect for apartment dwellers or anyone who wants fresh leaves in winter.
Use a south-facing window or grow lights. Catnip needs 12-16 hours of bright light daily. Colorado’s winter sun is weaker, so supplemental lighting helps.
Plant in pots with drainage holes. Use well-draining potting mix. Water when the top inch of soil dries out. Indoor catnip grows slower but stays productive for months.
Move pots outdoors in summer for stronger growth. Just harden them off gradually to avoid shock.
Common Problems And Solutions
Colorado gardeners face specific challenges when growing catnip. Here’s how to handle them.
Poor Germination
Catnip seeds need light and warmth to germinate. If seeds don’t sprout, the soil might be too cold or too wet. Wait until soil temperature reaches at least 60°F before planting.
Seeds can also be old. Catnip seeds remain viable for about 2-3 years. Use fresh seeds for best results.
Leggy Growth
If your catnip grows tall and spindly, it’s not getting enough light. Move plants to a sunnier spot or prune back to encourage bushiness.
Colorado’s intense sun can also cause leggy growth if plants are shaded by taller neighbors. Give catnip plenty of space.
Pests
Catnip naturally repels many pests, but aphids and spider mites can still appear. Spray plants with a strong stream of water to dislodge them. Neem oil works for severe infestations.
Colorado’s dry climate actually reduces pest problems. Most insects prefer humid conditions. Keep plants healthy and they’ll resist most issues.
Winter Kill
Catnip is hardy to zone 3, but harsh Colorado winters can damage plants. Apply mulch after the ground freezes to protect roots. In very cold areas, cover plants with row cover or straw.
Plants in pots need extra protection. Move pots to a sheltered location or wrap them in insulation.
Harvesting Catnip In Colorado
Harvest catnip leaves just before the plant flowers. That’s when the essential oils are strongest. For spring-planted catnip, harvest in late July to early August.
Cut stems in the morning after dew dries. Use sharp scissors or pruners. Leave at least 4-6 inches of stem so the plant can regrow.
Dry leaves in a warm, dark, well-ventilated area. Hang stems upside down or spread leaves on screens. Avoid direct sunlight, which degrades the oils.
Store dried catnip in airtight containers in a cool, dark place. It stays potent for about a year.
Frequently Asked Questions
Can I plant catnip seeds directly in Colorado soil?
Yes, direct sowing works well after the last frost. Just make sure the soil is warm enough and keep seeds moist until they germinate.
How long does catnip take to grow in Colorado?
From seed to harvest takes about 8-10 weeks. Transplants cut that time in half. Plants reach full size in 3-4 months.
Will catnip survive Colorado winters?
Yes, catnip is a hardy perennial that survives winter in most Colorado zones. Mulch helps protect roots in colder areas.
Can I grow catnip in pots on my balcony?
Absolutely. Pots work great for catnip. Use at least 12-inch pots with drainage holes. Bring pots indoors during severe cold snaps.
Does catnip attract cats or other animals?
Catnip attracts cats, bees, and butterflies. It repels mosquitoes and other pests. Protect young plants from curious cats by using cages or netting.
Final Tips For Success
Colorado’s climate is actually ideal for catnip. The dry air reduces disease, and the intense sun produces high oil content in the leaves. Your biggest challenge is timing the planting correctly.
Start seeds indoors if you want to extend the growing season. Use a heat mat to speed germination. Transplants give you more control over planting time.
Don’t overwater. This is the number one mistake Colorado gardeners make. Catnip prefers dry conditions once established.
Let some plants go to flower. The flowers attract beneficial insects and provide seeds for next year. Just be prepared for volunteers popping up everywhere.
With the right timing and care, you’ll have plenty of catnip for your feline friends and your garden’s ecosystem. Start planning now for a successful planting season.