Six Hints For Seedling Success

An ideal way to get a head start on spring gardening is raising your own seedlings. By growing your own seedlings, you will be ready to transplant them as soon as the outdoor soil is ready for planting. However, raising seedlings requires growers to pay attention to detail and get environmental conditions right for success. With that in mind, below are six hints for seedling success.

Use the Right Starting Soil Mix

Seedlings need the proper soil environment to give them a chance to thrive. That means the soil should be clean, sterile, and specifically formulated for use with seedlings.

Never reuse "old" soil from around your home for seedlings; soils that have been used for houseplants or gardening, for example, may contain fungi, viruses, bacteria or parasites that will attack and kill vulnerable seedlings. In addition, avoid soils that contain heavy doses of fertilizer and other chemicals, as these can "burn" seedlings during the earliest phases of growth.

Provide Adequate Lighting

If you are raising seedlings inside, they will need a source of light that mimics the sunlight they are missing. In addition, light fixtures should be kept extremely close to the tops of seedlings to maximize light availability; just be careful not to allow the tender seedlings to touch the bulbs, or they are likely to die due to overheating.

Buy Fresh Seeds

Seeds have a limited lifespan and will remain viable for a certain period of time. The specific viability period rarely exceeds five years and may be as short as a year for some plant species.

That is why it is always a good idea to purchase fresh seeds before each growing season. Keep seeds stored in a dark, cool location with temperatures maintained above freezing, such as your refrigerator. In addition, be sure to place seeds inside an airtight container that will provide protection against drying out.

Apply Fertilizer When Necessary

Once your seeds germinate, they will initially use nutrients inside the seed coat to fuel the growth of the tap root and the first pair of leaves. However, once the second set of leaves emerges, the nutrients in the seed coat will have been exhausted, and the seedlings will be left without food if you don't intervene.

To provide continued sustenance, dilute a high-quality fertilizer that is rich in phosphorous to half-strength, then add the liquid to the seedlings. Never use fertilizers at full strength, as they can injure the seedlings by providing too many nutrients at one time.

Pre-Germinate Seeds

Most gardeners sow several seeds in the same location to ensure at least one will germinate, and while this process works, there are some disadvantages. For example, if all seeds germinate, then all but one of the seedlings will need to be culled, thus potentially harming the remaining seedling by tearing at its roots.

This problem can be eliminated by pre-germinating seeds in a soil-free environment. To pre-germinate seeds, lay them neatly on damp paper towels inside a resealable container. Keep the container in a warm environment, and check on the seeds often. As soon as germination occurs, take the seed and place it in its seedling container for continued growth.

Harden Off Seedlings

Seedlings are raised in fairly low-stress environments that place little demand upon them, but your garden is probably not as forgiving to seedlings. If you were to transplant seedlings directly from their indoor location to the garden, they would likely die due to shock. That is why it is critical to harden off seedlings before they are moved to an outdoor location.

Hardening off seedlings isn't an exact science, but the basic principle is to gradually expose seedlings to outdoor conditions. This can be accomplished by moving seedling trays outside for a few hours per day or setting them outside in the cool, but not freezing, night air. Gradually "wean" seedlings from their comfortable indoor environment a little at a time as you approach the transplant date, and they will be ready to thrive by the time they are in the outdoor soil.

For additional advice, contact a local nursery.