For beginning farmers, March is the perfect time to start seeds indoors and get a head start on the growing season. Whether you’re growing vegetables, herbs, or flowers, starting your own seeds allows you to control growing conditions, save money on transplants, and produce healthier, more resilient plants. But it’s not as simple as just tossing seeds in the soil—timing, light, and care all make a difference.
Here’s what you need to know to get your seedlings off to a strong start, plus answers to some of the most common seed-starting issues.
Why Start Seeds Indoors?
Some crops can be direct-seeded into the ground once the weather warms up, but others—like tomatoes, peppers, and many herbs—need a longer growing season than what your local climate allows. Starting seeds indoors lets you bypass unpredictable weather, extend your growing season, and produce stronger, healthier transplants.
This approach is especially useful if you live in a short-season climate or if you want to maximize early production for market sales. It also gives you more control over what varieties you grow, which is especially important for organic or heirloom producers.
What You Need to Get Started
Setting up a successful seed-starting system doesn’t require an expensive greenhouse, but it does take a little planning. Here’s what you’ll need:
- Seed trays or containers – Any container will work as long as it has good drainage. Options include seed-starting flats, repurposed yogurt cups, or biodegradable pots.
- High-quality seed-starting mix – Regular potting soil is too dense. A light, well-draining seed-starting mix helps seedlings establish roots quickly.
- A reliable light source – A sunny window can work in some cases, but grow lights or LED shop lights placed 2-4 inches above seedlings will provide the best results.
- A heat source (if needed) – Most seeds germinate best at 65-75°F. If your growing space is cool, a heat mat can help keep soil warm enough for good germination.
- Check out Purdue Extensions Online Resources
Timing: When to Start Your Seeds
One of the biggest mistakes new growers make is starting seeds too early. If plants sit indoors too long, they can become leggy, rootbound, or stunted before they’re ready for transplanting.
Here’s a general guideline for when to start different crops:
| Crop |
Start Indoors (Weeks Before Last Frost) |
| Tomatoes & Peppers |
6-8 weeks |
| Brassicas (Broccoli, Cabbage, Kale) |
4-6 weeks |
| Herbs (Basil, Parsley) |
6-8 weeks |
| Squash & Cucumbers |
2-3 weeks (they grow fast!) |
To find your last frost date, check the USDA planting zone map or use a resource like Farmers’ Almanac.
Troubleshooting Common Seed-Starting Problems
Even experienced growers run into issues when starting seeds indoors. Here are answers to some of the most frequently asked questions:
1. Why aren’t my seeds germinating?
If seeds aren’t sprouting, it’s usually due to temperature, moisture, or seed viability issues.
✔ Check soil temperature – Most seeds need 65-75°F to germinate. A cold room or basement might be too chilly. Using a heat mat can help.
✔ Keep soil evenly moist – Seeds need consistent moisture but shouldn’t sit in soggy soil. Covering trays with a humidity dome can help.
✔ Use fresh seeds – Old seeds lose viability. If they’re more than two years old, do a germination test before planting.
2. Why are my seedlings tall and weak?
Leggy seedlings happen when there’s not enough light or too much warmth.
✔ Provide strong, direct light – Keep grow lights 2-4 inches above seedlings and adjust as plants grow.
✔ Increase air circulation – A small oscillating fan strengthens stems and prevents disease.
✔ Avoid over-fertilizing – Too much nitrogen can make plants grow too fast without strong stems.
3. Why are my seedlings wilting or dying?
Wilting or sudden collapse is often caused by overwatering or damping off, a fungal disease.
✔ Use well-draining seed-starting mix – Avoid heavy, compacted soil.
✔ Water from the bottom – Fill a tray under seedlings instead of watering overhead.
✔ Improve airflow – A small fan reduces humidity and prevents fungal growth.
4. Why are my seedlings turning yellow?
Yellowing leaves (chlorosis) can be a sign of nutrient deficiency, poor drainage, or transplant stress.
✔ Feed with a diluted organic fertilizer – Once seedlings have their first true leaves, feed lightly every 7-10 days.
✔ Ensure trays drain properly – If soil stays soggy, roots can’t absorb nutrients.
✔ Harden off seedlings before transplanting – Gradually introduce seedlings to outdoor conditions over 7-10 days before planting in the field.
Getting Ready for Transplanting
Before moving your seedlings outdoors, they need to adjust to real sunlight, wind, and temperature fluctuations. This process is called hardening off and should be done over 7-10 days:
- Start by placing seedlings outside for 1-2 hours per day in a shaded, protected spot.
- Gradually increase their time outside and move them into direct sunlight for part of the day.
- Reduce watering slightly to help them adjust to less controlled conditions.
- After a full week of hardening off, they’ll be ready for transplanting into the garden.
Have Questions
Starting seeds indoors is a simple, cost-effective way to get a jump on the season and improve success rates for crops. For beginning farmers, it’s a great way to gain confidence in managing crops before investing in large-scale production.
If you’re part of Veterans IN Farming, consider sharing your seed-starting success (or struggles!) with the community. Learning from each other’s experiences is one of the best ways to improve your farm operation.
Got questions? Reach out through Veterans IN Farming—via email or Facebook we’re here to help!