Tips on Starting Seeds

Starting seeds indoors is straightforward; you plant, water, and wait. But there are several seed-starting mistakes that can prevent your seeds from growing into strong, healthy seedlings. To grow healthier seedlings this spring, avoid these 12 common seed-starting mistakes.

1. Starting Seeds Too Early

Starting seeds too early means more time for pests and diseases to develop. Seedlings can also grow too large while waiting to go outside. They become rootbound and their growth becomes stunted. Ideally, start seeds six to eight weeks before they can be planted outdoors.

2. Using Old Seeds

Even when properly stored, seeds lose their viability within a couple of years. For better results, consider buying annually. When using old seed, sow more than you anticipate needing to account for failed germination. Alternatively, conduct a germination test to determine reliability.

3. Forgetting to Pretreat Seeds

Most vegetable seeds easily germinate but some annual and perennial seeds need pretreatment, such as cold stratification, to break dormancy.

4. Planting Seeds Too Deep

Generally, seeds should not be planted deeper than twice their width or diameter. If planted too deep, small seeds do not have enough energy to poke above the soil. As well, many flower seeds need light to germinate and should be left uncovered.

5. Not Labeling Pots

It is very easy to forget what seeds were planted, especially when experimenting with several different varieties of the same plant. Labeling is very important and can be as simple as using masking tape or a Popsicle stick.

6. Not Enough Light

Growing strong, healthy seedlings require lots of light. Seeds started indoors often need supplemental lighting. If your seedlings are leggy, leaning toward the light source, or growing slowly, you likely need more light.

7. Providing Too Much Water

The most common mistake is keeping the growing mix too wet. Excess moisture and damp conditions encourage fungi, especially damping off disease. Using a sterile, fast-draining seed-starting mix helps minimize soggy conditions and diseases.

8. Forgetting to Water

Unlike resilient older plants, seedlings are fragile and a few days of dry conditions can spell disaster. Check your seedlings daily to ensure they have adequate moisture. As seedlings get larger, their water requirements increase.

9. Not Thinning Seedlings

Thinning extra seedlings as soon as the true leaves appear reduces crowding and plant stress. Leaving too many seedlings in a small container forces them to compete for light, water, and nutrients. Use scissors to snip them off instead of pulling them.

10. Waiting Too Long to Pot Up

Seedlings begin to suffer when they become rootbound. Transplant them into larger containers as they grow.

11. Fertilizing Too Early or Too Late

Seedlings should not be fertilized when they are very young because this may damage the tender plants. The type of growing mix used determines when to start fertilizing. Soilless seed-starting mixes are often nutrient-poor, and the growing seedlings will soon need extra nutrients. Potting mixes usually have slow-release fertilizer added so the need to fertilize is less critical. Watch for signs of nutrient deficiencies as a guideline.

12. Not Hardening Off Seedlings

Seedlings that have been started indoors have been pampered and protected. Hardening off seedlings gradually introduces young plants to the harsh outdoors, where they will eventually thrive. Spend a week or ten days setting seedlings outdoors to acclimatize them. Start with a couple hours in a shady spot, increasing the time and light exposure daily.

Submitted by Brenda Gallagher