If you’re eager to start a container herb garden, your first question is likely, when can i plant herbs outside in pots? Getting the timing right is the single most important step for success. Planting too early risks frost damage, while planting too late shortens your growing season.
This guide will walk you through the best time for planting, based on your local climate and the herbs you choose. We’ll cover how to check your frost dates, which herbs are tough, and how to get your pots ready for a bountiful harvest.
When Can I Plant Herbs Outside In Pots
This isn’t a single date on the calendar. The best time for planting herbs outside depends on your region’s last expected spring frost. Tender herbs like basil and cilantro cannot handle frost at all, while hardy perennials like thyme and sage are more resilient.
Your goal is to wait until after the last frost date for your area. A good general rule is to plant your potted herbs outdoors in late spring, once nighttime temperatures are consistently above 50°F (10°C).
Understanding Your Frost Dates
Frost dates are your gardening calendar. The “last frost date” in spring is the average final day your area might experience a frost. The “first frost date” in fall is when freezing temps typically return.
- Find Your Zone: Use the USDA Plant Hardiness Zone Map. This number tells you your region’s average extreme minimum temperature.
- Check Local Dates: Search online for “[Your Town] last frost date” or use a gardening app. Your local cooperative extension office is a fantastic resource for this info.
- Use the Average as a Guide: These dates are averages, not guarantees. Weather can be unpredictable, so be prepared to protect your plants if a late cold snap arrives.
Herb Hardiness: Tender vs. Hardy
Not all herbs have the same cold tolerance. Grouping them helps you plan your planting schedule.
Frost-Tender Herbs (Plant After Last Frost)
These herbs originate from warm climates. They thrive in heat and will die if frosted. Wait until nights are warm.
- Basil
- Cilantro
- Lemongrass
- Parsley (can tolerate a light chill but is best planted after frost)
- Marjoram
Half-Hardy Herbs (Plant 1-2 Weeks Before Last Frost)
These can handle cooler soil and a light chill but not a hard freeze.
- Dill
- Chervil
- French Tarragon
Frost-Hardy Herbs (Plant in Early Spring)
These perennial herbs survive freezing winters and can be planted as soon as the ground is workable in spring, even if frosts are still possible.
- Thyme
- Rosemary (check variety for hardiness)
- Sage
- Oregano
- Mint
- Chives
How to Harden Off Your Herb Plants
If you started seeds indoors or bought plants from a greenhouse, you must “harden them off.” This is the process of gradually acclimating plants to outdoor conditions like sun, wind, and cooler temperatures. Skipping this can shock and stunt your herbs.
- Start Slow: Begin 7-10 days before your planned planting date.
- Choose a Sheltered Spot: Place pots in a shaded, protected area for just 1-2 hours on the first day.
- Gradually Increase: Each day, increase their time outside by an hour or two, slowly introducing them to morning sunlight.
- Monitor Closely: Watch for wilting or sunburn. If it occurs, bring them in and proceed more slowly.
- Leave Overnight: In the final few days, leave them out overnight if temperatures are safe.
- Plant: After a week or so, they are ready for their permanent outdoor spot.
Choosing and Preparing Your Pots
The right container sets the stage for healthy growth. Herbs generally need less room than vegetables, but drainage is non-negotiable.
- Drainage Holes: Every pot must have them. Soggy soil causes root rot.
- Size Matters: Most herbs do well in pots 6-12 inches deep. Fast-growers like mint need larger pots or their own container to prevent them from taking over.
- Material: Terracotta breathes well but dries out fast. Glazed ceramic is heavier. Plastic is lightweight and retains moisture longer. Choose based on your climate and watering habits.
- Soil is Key: Use a high-quality, well-draining potting mix. Do not use garden soil, which compacts in containers and hampers drainage. A mix labeled for containers or herbs is perfect.
Step-by-Step Planting Guide
- Final Weather Check: Ensure the forecast shows mild temperatures for the next week, with no frost.
- Prep the Pot: Fill your container with pre-moistened potting mix, leaving a couple inches from the rim.
- Gently Remove Plants: Loosen the root ball of your herb seedling. If roots are tightly wound, gently tease them apart.
- Plant at the Right Depth: Create a hole and set the plant in so it sits at the same level it was in its nursery pot. Firm the soil around it gently.
- Water Thoroughly: Water well after planting to settle the soil and eliminate air pockets around the roots.
- Label: It’s easy to forget whats what, especially when seedlings are small. Use a plant marker.
Early Season Care and Protection
Even after the last frost date, spring weather can be tricky. Be prepared to protect your new plantings.
- Frost Cloth: Keep some handy. If a late frost is predicted, drape it over your pots in the evening.
- Move Pots: The beauty of containers! If a cold night or a harsh storm is coming, you can temporarily move them to a garage or sheltered porch.
- Hold Off on Fertilizer: Wait 3-4 weeks after planting to fertilize. Let the plants establish roots first. A balanced, organic liquid fertilizer works great for herbs.
What if You Plant Too Early?
If a surprise frost threatens your tender herbs, act quickly. Cover them immediately with frost cloth, blankets, or even cardboard. For a very light frost, watering the soil lightly the evening before can sometimes help, as moist soil retains heat better than dry soil. Unfortunately, severely damaged foliage may not recover, but the plant might regrow from the roots if it wasn’t a total kill.
FAQ: Your Planting Questions Answered
Can I plant potted herbs outside in early spring?
You can plant hardy perennial herbs (thyme, sage, mint) in early spring. For tender herbs (basil, cilantro), you must wait until all danger of frost has passed, which is usually late spring.
What month is best for planting herbs?
For most regions, the best months are May and June, after the last frost. In warmer climates (zones 9-11), you can often plant year-round, avoiding the peak summer heat.
How do I know when its safe to plant?
It’s safe when your local last frost date has passed and the nightly low temperatures are consistently above 50°F. Watching the 10-day weather forecast is also a smart habit.
Can I leave my potted herbs outside overnight?
Once they are hardened off and the temperatures are safely above the needs of the specific herb, yes. Before that, or if a cold night is forecast, it’s safer to bring them in or provide protection.
Is it better to start herbs from seed or plants?
Starting from seed is cheaper and offers more variety. Starting with nursery plants gives you a head start and is easier for beginners. Some herbs, like parsley, have slow germination and are often bought as plants.
Timing your herb planting correctly sets you up for a season of easy growth. By paying attention to frost dates, understanding your herbs’ needs, and taking a week to harden off seedlings, you’ll avoid the most common pitfalls. Your reward will be pots full of fresh flavor right outside your door, ready to enhance your cooking all summer long. Remember, patience in spring leads to abundance later on.