When to Start Tomatillo Seeds Indoors?
Starting tomatillo seeds indoors is best done 6-8 weeks before your last expected spring frost. This timing ensures healthy transplants ready to thrive once outdoor conditions are suitable for these warm-weather crops.
The Allure of Tomatillos: A Mexican Kitchen Staple
Tomatillos, also known as Mexican husk tomatoes, are increasingly popular among home gardeners seeking unique and flavorful additions to their culinary repertoire. Unlike their tomato cousins, tomatillos have a tart, citrusy tang and are encased in a papery husk. They’re essential for making salsas verde, stews, and various other Mexican dishes.
Why Start Tomatillos Indoors?
Starting tomatillo seeds indoors offers several distinct advantages:
- Extended Growing Season: Tomatillos require a long growing season, typically 75-100 days. Starting them indoors allows you to get a head start, especially in regions with shorter summers.
- Control Over Environment: Indoor seed starting provides a controlled environment with consistent temperature, light, and moisture levels, crucial for successful germination and seedling development.
- Healthier Transplants: Indoor-started seedlings are often sturdier and more resistant to pests and diseases than those directly sown outdoors.
- Cost Savings: Growing your own tomatillo plants from seed is generally more economical than purchasing transplants from a nursery.
Determining the Ideal Time: The Frost Factor
The most critical factor in determining when to start tomatillo seeds indoors is your region’s last expected spring frost date. As mentioned, aim for 6-8 weeks before this date. You can find this information from your local weather service, agricultural extension office, or online gardening resources.
The Step-by-Step Process of Starting Tomatillo Seeds Indoors
Here’s a breakdown of the process:
- Gather Your Supplies: You’ll need:
- Tomatillo seeds
- Seed starting trays or small pots
- Seed starting mix
- Watering can or spray bottle
- Heat mat (optional but recommended)
- Grow lights
- Plant labels
- Sow the Seeds: Fill your seed starting trays or pots with seed starting mix. Sow seeds about 1/4 inch deep and gently water.
- Provide Warmth and Moisture: Place the trays or pots on a heat mat (if using) and cover them with a humidity dome or plastic wrap to maintain moisture. Aim for a soil temperature of 70-80°F (21-27°C).
- Provide Light: Once seedlings emerge, remove the humidity dome and place them under grow lights. Keep the lights on for 14-16 hours per day.
- Water Carefully: Water the seedlings when the soil surface feels dry to the touch. Avoid overwatering, which can lead to damping off.
- Harden Off Seedlings: About a week before transplanting, gradually acclimate the seedlings to outdoor conditions by exposing them to increasing amounts of sunlight and fresh air each day.
Hardening Off: Preparing Seedlings for the Real World
Hardening off is the crucial process of acclimating your indoor-grown tomatillo seedlings to the harsher conditions of the outdoor environment. This involves gradually exposing them to sunlight, wind, and temperature fluctuations. A week before transplanting, start by placing the seedlings outdoors in a sheltered location for an hour or two each day, gradually increasing the time until they can tolerate a full day outside.
Common Mistakes to Avoid
- Starting Too Early: Starting seeds too early can result in leggy, weak seedlings that are difficult to transplant.
- Overwatering: Overwatering is a common cause of damping off, a fungal disease that can kill young seedlings.
- Insufficient Light: Seedlings need adequate light to grow strong and healthy. If they don’t receive enough light, they will become leggy and weak.
- Neglecting Hardening Off: Failing to harden off seedlings before transplanting can shock them and stunt their growth.
- Using Garden Soil for Starting Seeds: Garden soil is often too heavy and compacted for seed starting and may contain diseases or pests.
Key Considerations for a Successful Start
| Factor | Recommendation |
|---|---|
| Timing | 6-8 weeks before last expected spring frost |
| Soil | Use seed starting mix, not garden soil |
| Temperature | 70-80°F (21-27°C) for germination, slightly cooler after |
| Light | 14-16 hours per day with grow lights |
| Watering | Water when soil surface is dry to the touch, avoid overwatering |
| Hardening Off | Gradually acclimate seedlings to outdoor conditions |
FAQ: Tomatillo Seed Starting
What if I miss the 6-8 week window?
It’s not the end of the world. You can still start tomatillo seeds indoors, but your harvest might be delayed. Alternatively, you can purchase transplants from a reputable nursery.
Can I start tomatillo seeds directly in the garden?
While possible, direct sowing is generally not recommended in colder climates due to the long growing season required. In warmer climates with long growing seasons, you can try, but be prepared to protect the seedlings from extreme weather and pests.
How long does it take for tomatillo seeds to germinate?
Tomatillo seeds typically germinate in 7-14 days under optimal conditions.
What kind of grow lights are best for starting tomatillo seeds?
Fluorescent grow lights or LED grow lights are both excellent options. Ensure the lights provide sufficient intensity for healthy seedling development.
How often should I water my tomatillo seedlings?
Water when the soil surface feels dry to the touch. Avoid overwatering, as this can lead to fungal diseases.
How do I know if my seedlings are getting enough light?
Healthy seedlings should be compact and green. If they are leggy (tall and spindly) or pale, they likely need more light.
What is “damping off” and how can I prevent it?
Damping off is a fungal disease that affects young seedlings, causing them to rot at the soil line. Prevent it by using sterile seed starting mix, avoiding overwatering, and ensuring good air circulation.
When should I transplant my tomatillo seedlings into larger pots?
Once the seedlings have developed their first set of true leaves (the leaves that appear after the cotyledons, or seed leaves), you can transplant them into larger pots (e.g., 4-inch pots). Use a well-draining potting mix.
How do I prepare my garden bed for transplanting tomatillo seedlings?
Choose a sunny location with well-drained soil. Amend the soil with compost or other organic matter to improve fertility and drainage. Tomatillos need at least 6 hours of sunlight per day.
How far apart should I plant tomatillo seedlings in the garden?
Space tomatillo plants 2-3 feet apart in rows that are 3-4 feet apart.
Do tomatillo plants need support?
Yes, tomatillo plants can become quite large and sprawling, so they benefit from staking or caging.
Are tomatillos self-pollinating?
While they can self-pollinate, tomatillos produce more abundant fruit when cross-pollinated. Planting multiple tomatillo plants near each other will encourage cross-pollination.