There are clear signs that your plugs are ready to transplant to larger containers. The most visible is the presence of true leaves. These are the leaves that grow following the cotyledons. Cotyledons are embryonic leaves, the first set of leaves to appear after a seed germinates. They look like rabbit ears, with an ovate shape and smooth margins. True leaves have the shape of leaves on the mature plant, only smaller. You can recognize the true leaves on a tomato transplant because they have indented margins. If you handle your plugs with care you can move them when they have only one set of true leaves, but it is more common to transplant when there are two sets because the plugs are sturdier at this stage. You can transplant the plugs of tomatoes, peppers and eggplants for several weeks after they enter the true leaf stage. The plugs begin to lose their well-balanced, fresh, new look, but you can still produce a good plant with larger, older plugs.
Handle your plugs with care when you transplant. They are delicate, and you can damage the stems or pull out the roots, setting back or permanently damaging the plant. The best way is to pull them gently where the leaves meet the stem, without applying too much pressure. Stems are responsible for the movement of fluids through the plant. In general, a good stem means a good plant. If you squeeze too tightly you’ll harm the stem, so work slowly and carefully until you develop a knack for handling your plugs.
If you find that your plugs are not releasing from your transplant trays without tearing, try using a tool to dislodge them. We scoop ours out using oyster shuckers, which have small knobs for handles and dull blades. They are ideal for the job.
When transplanting, deeper is better. When you transplant a vegetable plug you give it a new beginning, a chance to form an improved, strong, even perfect structure. Bends in the stems can be corrected by deep planting. Deeply planted tomatoes develop a larger root system, because the tiny hairs you see along the stem are adventitious roots. All they need to begin growing is contact with soil. You can transplant almost the length of the stem, leaving just one or two sets of true leaves above the soil level.
We always moisten the soil in the transplant containers prior to transplanting. This allows us to make a well-formed hole in the soil to receive the roots and stem. It also reduces transplant shock, getting the plugs off to a smooth start. In fact, we prefer to water at least twice prior to transplanting, leaving an interval between watering to insure that moisture thoroughly permeates the soil.
A dibble makes a nice, well-formed, centered hole in moistened soil. Your finger can do the same job, although it will suffer some wear and tear in the process!
After transplanting the plugs we water at least twice again to insure that there is no lack of moisture available to the roots in the first several days following. There is evidence that watering with fish emulsion immediately after transplanting is even more effective than water alone, giving the plugs an added boost that will lead to larger, healthier, more productive plants.
At this stage your immature seedlings need the maximum light available. Direct light 16 hours a day is ideal. Full, direct sun promotes healthy, disease-free plants with dense cell structure that is made evident by strong, stocky stems and a compact appearance. Depending on the quality of the light and the size of your containers, you can hold your plants anywhere from three to six weeks before transplanting into the garden. During this time, keep them moist and avoid the extremes of too wet and too dry. A steady supply of moisture promotes continuous growth, and that’s what you want.
On a related topic, The Natural Gardening Company has an experiment and contest underway to find out which region of the country has the best climate for growing tomatoes. Gardeners from all 50 states have been invited to participate and it is no more difficult than planting tomatoes on a specific schedule in your own backyard.
Here’s a link to the TomatoCam
Next time we’ll take a look at drip irrigation. See you in two weeks!