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The Plant Doctor: Germinated seedlings ready to grow outside

By Harvey D. Goodman

After reading the first of this series you should have gathered your seed packets (although with 25 inches of snow in my garden that seems to be the last thing on my mind), chosen an appropriate planting pot and mixed a concoction of your choosing, which we have referred to as a soiless mixture. Larger pots are on standby as we plan to transplant the seedlings as they outgrow the germination pots.

If you have not had the opportunity to review part 1 of this series, contact me at the e-mail address listed below for a copy.

In listing the optimum range for seed germination, horticulturists use soil temperature, not air temperature. Most seeds germinate best at 78 degrees, but a few, and you will have to check the packet, germinate in temperatures as low as 68 degrees and others as high as 85 degrees. Corn enjoys a temperature in excess of 95 degrees.

A soil thermometer will help you monitor the temperature. Moving the pot atop a radiator or to a cool windowsill will help you adjust and maintain the temperature.

After the seeds have germinated, a temperature around 70 degrees is optimal. Too much warmth will cause the plants to grow spindly, and too little warmth will cause growth to be stunted.

Seeds do not require light while germinating; however, shortly after the first shoots break the surface of the soil, the packet must be moved to a sunny location. If you wait too long the seedlings will grow tall and leggy — a condition that is almost impossible to correct.

Most seedlings require as much as 12 to 14 hours of direct light in order to manufacture enough food for healthy stems and leaves. Unfortunately, we will not get that amount of light until mid-April at the earliest. Thus you probably will have to supplement the windowsill light with some form of artificial light.

Most preferred lighting is Grow-Lux bulbs, or full-spectrum fluorescent bulbs. Household or shop incandescent bulbs produce too much heat and lack the blue-red spectra needed for food production.

Newly germinated seedlings require consistent moisture. The soil should be kept moist but not soggy. Watering must be thorough; the water must reach the bottom of the pot, not just the surface of the soil.

The air in your home during the winter is very dry. In order to maintain a proper humidity level for the seedlings (around 50 percent to 70 percent), you may wish to place the pot in a waterproof tray filled with small stones (gravel) and water. As the water evaporates from the tray, the air around the seedlings retains some of the moisture.

Recall the soiless mixture we recommended. It is excellent for germinating seeds but totally devoid of nutrients. Soon after the seedlings produce their second set of true leaves, they should be fed initially with a half dose of fertilizer once a week for the first two weeks. Increase the dosage to full strength after three to four weeks. Most organic fertilizers, such as Miracle-Gro, contain the needed basic and micronutrient minerals required for proper growth and development.

Once the weather has started to warm up, you can begin the “hardening off” process by gradually exposing them to the great outdoors. Increase their exposure about one hour a day for about one week prior to planting out of doors. Transplant by gently removing the root ball. Never remove seedlings by their stem — it is far too fragile and can be bent or crushed.

Follow the directions on the seed packets as to best location in your garden. Some require direct light while others prefer a shaded location. Watering frequency and amount of space between plants will likewise be prescribed on the seed packet.

I hope by the time you read this column the mounds of snow in my backyard will have melted and at best be nothing more than a memory. If you close your eyes real tight and relax on a comfortable chair, you can almost imagine the delicate seedlings popping out of the soil..

Questions or concerns regarding gardening or plant care may be addressed by e-mail to Harvey.Goodman@att.net.